# # Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # import copy import sys import os import operator import shlex import warnings import heapq import bisect import random from subprocess import Popen, PIPE from threading import Thread from collections import defaultdict from itertools import chain from functools import reduce from math import sqrt, log, isinf, isnan, pow, ceil from typing import ( Any, Callable, Dict, Generic, Hashable, Iterable, Iterator, IO, List, NoReturn, Optional, Sequence, Tuple, Union, TypeVar, cast, overload, TYPE_CHECKING, ) from pyspark.java_gateway import local_connect_and_auth from pyspark.serializers import ( AutoBatchedSerializer, BatchedSerializer, NoOpSerializer, CartesianDeserializer, CloudPickleSerializer, PairDeserializer, CPickleSerializer, Serializer, pack_long, read_int, write_int, ) from pyspark.join import ( python_join, python_left_outer_join, python_right_outer_join, python_full_outer_join, python_cogroup, ) from pyspark.statcounter import StatCounter from pyspark.rddsampler import RDDSampler, RDDRangeSampler, RDDStratifiedSampler from pyspark.storagelevel import StorageLevel from pyspark.resource.requests import ExecutorResourceRequests, TaskResourceRequests from pyspark.resource.profile import ResourceProfile from pyspark.resultiterable import ResultIterable from pyspark.shuffle import ( Aggregator, ExternalMerger, get_used_memory, ExternalSorter, ExternalGroupBy, ) from pyspark.traceback_utils import SCCallSiteSync from pyspark.util import fail_on_stopiteration, _parse_memory if TYPE_CHECKING: import socket import io from pyspark._typing import NonUDFType from pyspark._typing import S, NumberOrArray from pyspark.context import SparkContext from pyspark.sql.pandas._typing import ( PandasScalarUDFType, PandasGroupedMapUDFType, PandasGroupedAggUDFType, PandasWindowAggUDFType, PandasScalarIterUDFType, PandasMapIterUDFType, PandasCogroupedMapUDFType, ArrowMapIterUDFType, PandasGroupedMapUDFWithStateType, ) from pyspark.sql.dataframe import DataFrame from pyspark.sql.types import AtomicType, StructType from pyspark.sql._typing import AtomicValue, RowLike, SQLBatchedUDFType from py4j.java_gateway import JavaObject from py4j.java_collections import JavaArray T = TypeVar("T") T_co = TypeVar("T_co", covariant=True) U = TypeVar("U") K = TypeVar("K", bound=Hashable) V = TypeVar("V") V1 = TypeVar("V1") V2 = TypeVar("V2") V3 = TypeVar("V3") __all__ = ["RDD"] class PythonEvalType: """ Evaluation type of python rdd. These values are internal to PySpark. These values should match values in org.apache.spark.api.python.PythonEvalType. """ NON_UDF: "NonUDFType" = 0 SQL_BATCHED_UDF: "SQLBatchedUDFType" = 100 SQL_SCALAR_PANDAS_UDF: "PandasScalarUDFType" = 200 SQL_GROUPED_MAP_PANDAS_UDF: "PandasGroupedMapUDFType" = 201 SQL_GROUPED_AGG_PANDAS_UDF: "PandasGroupedAggUDFType" = 202 SQL_WINDOW_AGG_PANDAS_UDF: "PandasWindowAggUDFType" = 203 SQL_SCALAR_PANDAS_ITER_UDF: "PandasScalarIterUDFType" = 204 SQL_MAP_PANDAS_ITER_UDF: "PandasMapIterUDFType" = 205 SQL_COGROUPED_MAP_PANDAS_UDF: "PandasCogroupedMapUDFType" = 206 SQL_MAP_ARROW_ITER_UDF: "ArrowMapIterUDFType" = 207 SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE: "PandasGroupedMapUDFWithStateType" = 208 def portable_hash(x: Hashable) -> int: """ This function returns consistent hash code for builtin types, especially for None and tuple with None. The algorithm is similar to that one used by CPython 2.7 Examples -------- >>> portable_hash(None) 0 >>> portable_hash((None, 1)) & 0xffffffff 219750521 """ if "PYTHONHASHSEED" not in os.environ: raise RuntimeError("Randomness of hash of string should be disabled via PYTHONHASHSEED") if x is None: return 0 if isinstance(x, tuple): h = 0x345678 for i in x: h ^= portable_hash(i) h *= 1000003 h &= sys.maxsize h ^= len(x) if h == -1: h = -2 return int(h) return hash(x) class BoundedFloat(float): """ Bounded value is generated by approximate job, with confidence and low bound and high bound. Examples -------- >>> BoundedFloat(100.0, 0.95, 95.0, 105.0) 100.0 """ confidence: float low: float high: float def __new__(cls, mean: float, confidence: float, low: float, high: float) -> "BoundedFloat": obj = float.__new__(cls, mean) obj.confidence = confidence obj.low = low obj.high = high return obj def _create_local_socket(sock_info: "JavaArray") -> "io.BufferedRWPair": """ Create a local socket that can be used to load deserialized data from the JVM Parameters ---------- sock_info : tuple Tuple containing port number and authentication secret for a local socket. Returns ------- sockfile file descriptor of the local socket """ sockfile: "io.BufferedRWPair" sock: "socket.socket" port: int = sock_info[0] auth_secret: str = sock_info[1] sockfile, sock = local_connect_and_auth(port, auth_secret) # The RDD materialization time is unpredictable, if we set a timeout for socket reading # operation, it will very possibly fail. See SPARK-18281. sock.settimeout(None) return sockfile def _load_from_socket(sock_info: "JavaArray", serializer: Serializer) -> Iterator[Any]: """ Connect to a local socket described by sock_info and use the given serializer to yield data Parameters ---------- sock_info : tuple Tuple containing port number and authentication secret for a local socket. serializer : class:`Serializer` The PySpark serializer to use Returns ------- result of meth:`Serializer.load_stream`, usually a generator that yields deserialized data """ sockfile = _create_local_socket(sock_info) # The socket will be automatically closed when garbage-collected. return serializer.load_stream(sockfile) def _local_iterator_from_socket(sock_info: "JavaArray", serializer: Serializer) -> Iterator[Any]: class PyLocalIterable: """Create a synchronous local iterable over a socket""" def __init__(self, _sock_info: "JavaArray", _serializer: Serializer): port: int auth_secret: str jsocket_auth_server: "JavaObject" port, auth_secret, self.jsocket_auth_server = _sock_info self._sockfile = _create_local_socket((port, auth_secret)) self._serializer = _serializer self._read_iter: Iterator[Any] = iter([]) # Initialize as empty iterator self._read_status = 1 def __iter__(self) -> Iterator[Any]: while self._read_status == 1: # Request next partition data from Java write_int(1, self._sockfile) self._sockfile.flush() # If response is 1 then there is a partition to read, if 0 then fully consumed self._read_status = read_int(self._sockfile) if self._read_status == 1: # Load the partition data as a stream and read each item self._read_iter = self._serializer.load_stream(self._sockfile) for item in self._read_iter: yield item # An error occurred, join serving thread and raise any exceptions from the JVM elif self._read_status == -1: self.jsocket_auth_server.getResult() def __del__(self) -> None: # If local iterator is not fully consumed, if self._read_status == 1: try: # Finish consuming partition data stream for _ in self._read_iter: pass # Tell Java to stop sending data and close connection write_int(0, self._sockfile) self._sockfile.flush() except Exception: # Ignore any errors, socket is automatically closed when garbage-collected pass return iter(PyLocalIterable(sock_info, serializer)) class Partitioner: def __init__(self, numPartitions: int, partitionFunc: Callable[[Any], int]): self.numPartitions = numPartitions self.partitionFunc = partitionFunc def __eq__(self, other: Any) -> bool: return ( isinstance(other, Partitioner) and self.numPartitions == other.numPartitions and self.partitionFunc == other.partitionFunc ) def __call__(self, k: Any) -> int: return self.partitionFunc(k) % self.numPartitions [docs]class RDD(Generic[T_co]): """ A Resilient Distributed Dataset (RDD), the basic abstraction in Spark. Represents an immutable, partitioned collection of elements that can be operated on in parallel. """ def __init__( self, jrdd: "JavaObject", ctx: "SparkContext", jrdd_deserializer: Serializer = AutoBatchedSerializer(CPickleSerializer()), ): self._jrdd = jrdd self.is_cached = False self.is_checkpointed = False self.has_resource_profile = False self.ctx = ctx self._jrdd_deserializer = jrdd_deserializer self._id = jrdd.id() self.partitioner: Optional[Partitioner] = None def _pickled(self: "RDD[T]") -> "RDD[T]": return self._reserialize(AutoBatchedSerializer(CPickleSerializer())) [docs] def id(self) -> int: """ A unique ID for this RDD (within its SparkContext). .. versionadded:: 0.7.0 Returns ------- int The unique ID for this :class:`RDD` Examples -------- >>> rdd = sc.range(5) >>> rdd.id() # doctest: +SKIP 3 """ return self._id def __repr__(self) -> str: return self._jrdd.toString() def __getnewargs__(self) -> NoReturn: # This method is called when attempting to pickle an RDD, which is always an error: raise RuntimeError( "It appears that you are attempting to broadcast an RDD or reference an RDD from an " "action or transformation. RDD transformations and actions can only be invoked by the " "driver, not inside of other transformations; for example, " "rdd1.map(lambda x: rdd2.values.count() * x) is invalid because the values " "transformation and count action cannot be performed inside of the rdd1.map " "transformation. For more information, see SPARK-5063." ) @property def context(self) -> "SparkContext": """ The :class:`SparkContext` that this RDD was created on. .. versionadded:: 0.7.0 Returns ------- :class:`SparkContext` The :class:`SparkContext` that this RDD was created on Examples -------- >>> rdd = sc.range(5) >>> rdd.context <SparkContext ...> >>> rdd.context is sc True """ return self.ctx [docs] def cache(self: "RDD[T]") -> "RDD[T]": """ Persist this RDD with the default storage level (`MEMORY_ONLY`). .. versionadded:: 0.7.0 Returns ------- :class:`RDD` The same :class:`RDD` with storage level set to `MEMORY_ONLY` See Also -------- :meth:`RDD.persist` :meth:`RDD.unpersist` :meth:`RDD.getStorageLevel` Examples -------- >>> rdd = sc.range(5) >>> rdd2 = rdd.cache() >>> rdd2 is rdd True >>> str(rdd.getStorageLevel()) 'Memory Serialized 1x Replicated' >>> _ = rdd.unpersist() """ self.is_cached = True self.persist(StorageLevel.MEMORY_ONLY) return self [docs] def persist(self: "RDD[T]", storageLevel: StorageLevel = StorageLevel.MEMORY_ONLY) -> "RDD[T]": """ Set this RDD's storage level to persist its values across operations after the first time it is computed. This can only be used to assign a new storage level if the RDD does not have a storage level set yet. If no storage level is specified defaults to (`MEMORY_ONLY`). .. versionadded:: 0.9.1 Parameters ---------- storageLevel : :class:`StorageLevel`, default `MEMORY_ONLY` the target storage level Returns ------- :class:`RDD` The same :class:`RDD` with storage level set to `storageLevel`. See Also -------- :meth:`RDD.cache` :meth:`RDD.unpersist` :meth:`RDD.getStorageLevel` Examples -------- >>> rdd = sc.parallelize(["b", "a", "c"]) >>> rdd.persist().is_cached True >>> str(rdd.getStorageLevel()) 'Memory Serialized 1x Replicated' >>> _ = rdd.unpersist() >>> rdd.is_cached False >>> from pyspark import StorageLevel >>> rdd2 = sc.range(5) >>> _ = rdd2.persist(StorageLevel.MEMORY_AND_DISK) >>> rdd2.is_cached True >>> str(rdd2.getStorageLevel()) 'Disk Memory Serialized 1x Replicated' Can not override existing storage level >>> _ = rdd2.persist(StorageLevel.MEMORY_ONLY_2) Traceback (most recent call last): ... py4j.protocol.Py4JJavaError: ... Assign another storage level after `unpersist` >>> _ = rdd2.unpersist() >>> rdd2.is_cached False >>> _ = rdd2.persist(StorageLevel.MEMORY_ONLY_2) >>> str(rdd2.getStorageLevel()) 'Memory Serialized 2x Replicated' >>> rdd2.is_cached True >>> _ = rdd2.unpersist() """ self.is_cached = True javaStorageLevel = self.ctx._getJavaStorageLevel(storageLevel) self._jrdd.persist(javaStorageLevel) return self [docs] def unpersist(self: "RDD[T]", blocking: bool = False) -> "RDD[T]": """ Mark the RDD as non-persistent, and remove all blocks for it from memory and disk. .. versionadded:: 0.9.1 Parameters ---------- blocking : bool, optional, default False whether to block until all blocks are deleted .. versionadded:: 3.0.0 Returns ------- :class:`RDD` The same :class:`RDD` See Also -------- :meth:`RDD.cache` :meth:`RDD.persist` :meth:`RDD.getStorageLevel` Examples -------- >>> rdd = sc.range(5) >>> rdd.is_cached False >>> _ = rdd.unpersist() >>> rdd.is_cached False >>> _ = rdd.cache() >>> rdd.is_cached True >>> _ = rdd.unpersist() >>> rdd.is_cached False >>> _ = rdd.unpersist() """ self.is_cached = False self._jrdd.unpersist(blocking) return self [docs] def checkpoint(self) -> None: """ Mark this RDD for checkpointing. It will be saved to a file inside the checkpoint directory set with :meth:`SparkContext.setCheckpointDir` and all references to its parent RDDs will be removed. This function must be called before any job has been executed on this RDD. It is strongly recommended that this RDD is persisted in memory, otherwise saving it on a file will require recomputation. .. versionadded:: 0.7.0 See Also -------- :meth:`RDD.isCheckpointed` :meth:`RDD.getCheckpointFile` :meth:`RDD.localCheckpoint` :meth:`SparkContext.setCheckpointDir` :meth:`SparkContext.getCheckpointDir` Examples -------- >>> rdd = sc.range(5) >>> rdd.is_checkpointed False >>> rdd.getCheckpointFile() == None True >>> rdd.checkpoint() >>> rdd.is_checkpointed True >>> rdd.getCheckpointFile() == None True >>> rdd.count() 5 >>> rdd.is_checkpointed True >>> rdd.getCheckpointFile() == None False """ self.is_checkpointed = True self._jrdd.rdd().checkpoint() [docs] def isCheckpointed(self) -> bool: """ Return whether this RDD is checkpointed and materialized, either reliably or locally. .. versionadded:: 0.7.0 Returns ------- bool whether this :class:`RDD` is checkpointed and materialized, either reliably or locally See Also -------- :meth:`RDD.checkpoint` :meth:`RDD.getCheckpointFile` :meth:`SparkContext.setCheckpointDir` :meth:`SparkContext.getCheckpointDir` """ return self._jrdd.rdd().isCheckpointed() [docs] def localCheckpoint(self) -> None: """ Mark this RDD for local checkpointing using Spark's existing caching layer. This method is for users who wish to truncate RDD lineages while skipping the expensive step of replicating the materialized data in a reliable distributed file system. This is useful for RDDs with long lineages that need to be truncated periodically (e.g. GraphX). Local checkpointing sacrifices fault-tolerance for performance. In particular, checkpointed data is written to ephemeral local storage in the executors instead of to a reliable, fault-tolerant storage. The effect is that if an executor fails during the computation, the checkpointed data may no longer be accessible, causing an irrecoverable job failure. This is NOT safe to use with dynamic allocation, which removes executors along with their cached blocks. If you must use both features, you are advised to set `spark.dynamicAllocation.cachedExecutorIdleTimeout` to a high value. The checkpoint directory set through :meth:`SparkContext.setCheckpointDir` is not used. .. versionadded:: 2.2.0 See Also -------- :meth:`RDD.checkpoint` :meth:`RDD.isLocallyCheckpointed` Examples -------- >>> rdd = sc.range(5) >>> rdd.isLocallyCheckpointed() False >>> rdd.localCheckpoint() >>> rdd.isLocallyCheckpointed() True """ self._jrdd.rdd().localCheckpoint() [docs] def isLocallyCheckpointed(self) -> bool: """ Return whether this RDD is marked for local checkpointing. Exposed for testing. .. versionadded:: 2.2.0 Returns ------- bool whether this :class:`RDD` is marked for local checkpointing See Also -------- :meth:`RDD.localCheckpoint` """ return self._jrdd.rdd().isLocallyCheckpointed() [docs] def getCheckpointFile(self) -> Optional[str]: """ Gets the name of the file to which this RDD was checkpointed Not defined if RDD is checkpointed locally. .. versionadded:: 0.7.0 Returns ------- str the name of the file to which this :class:`RDD` was checkpointed See Also -------- :meth:`RDD.checkpoint` :meth:`SparkContext.setCheckpointDir` :meth:`SparkContext.getCheckpointDir` """ checkpointFile = self._jrdd.rdd().getCheckpointFile() return checkpointFile.get() if checkpointFile.isDefined() else None [docs] def cleanShuffleDependencies(self, blocking: bool = False) -> None: """ Removes an RDD's shuffles and it's non-persisted ancestors. When running without a shuffle service, cleaning up shuffle files enables downscaling. If you use the RDD after this call, you should checkpoint and materialize it first. .. versionadded:: 3.3.0 Parameters ---------- blocking : bool, optional, default False whether to block on shuffle cleanup tasks Notes ----- This API is a developer API. """ self._jrdd.rdd().cleanShuffleDependencies(blocking) [docs] def map(self: "RDD[T]", f: Callable[[T], U], preservesPartitioning: bool = False) -> "RDD[U]": """ Return a new RDD by applying a function to each element of this RDD. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to run on each element of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to all elements See Also -------- :meth:`RDD.flatMap` :meth:`RDD.mapPartitions` :meth:`RDD.mapPartitionsWithIndex` :meth:`RDD.mapPartitionsWithSplit` Examples -------- >>> rdd = sc.parallelize(["b", "a", "c"]) >>> sorted(rdd.map(lambda x: (x, 1)).collect()) [('a', 1), ('b', 1), ('c', 1)] """ def func(_: int, iterator: Iterable[T]) -> Iterable[U]: return map(fail_on_stopiteration(f), iterator) return self.mapPartitionsWithIndex(func, preservesPartitioning) [docs] def flatMap( self: "RDD[T]", f: Callable[[T], Iterable[U]], preservesPartitioning: bool = False ) -> "RDD[U]": """ Return a new RDD by first applying a function to all elements of this RDD, and then flattening the results. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to turn a T into a sequence of U preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to all elements See Also -------- :meth:`RDD.map` :meth:`RDD.mapPartitions` :meth:`RDD.mapPartitionsWithIndex` :meth:`RDD.mapPartitionsWithSplit` Examples -------- >>> rdd = sc.parallelize([2, 3, 4]) >>> sorted(rdd.flatMap(lambda x: range(1, x)).collect()) [1, 1, 1, 2, 2, 3] >>> sorted(rdd.flatMap(lambda x: [(x, x), (x, x)]).collect()) [(2, 2), (2, 2), (3, 3), (3, 3), (4, 4), (4, 4)] """ def func(_: int, iterator: Iterable[T]) -> Iterable[U]: return chain.from_iterable(map(fail_on_stopiteration(f), iterator)) return self.mapPartitionsWithIndex(func, preservesPartitioning) [docs] def mapPartitions( self: "RDD[T]", f: Callable[[Iterable[T]], Iterable[U]], preservesPartitioning: bool = False ) -> "RDD[U]": """ Return a new RDD by applying a function to each partition of this RDD. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to run on each partition of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each partition See Also -------- :meth:`RDD.map` :meth:`RDD.flatMap` :meth:`RDD.mapPartitionsWithIndex` :meth:`RDD.mapPartitionsWithSplit` :meth:`RDDBarrier.mapPartitions` Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 2) >>> def f(iterator): yield sum(iterator) >>> rdd.mapPartitions(f).collect() [3, 7] """ def func(_: int, iterator: Iterable[T]) -> Iterable[U]: return f(iterator) return self.mapPartitionsWithIndex(func, preservesPartitioning) [docs] def mapPartitionsWithIndex( self: "RDD[T]", f: Callable[[int, Iterable[T]], Iterable[U]], preservesPartitioning: bool = False, ) -> "RDD[U]": """ Return a new RDD by applying a function to each partition of this RDD, while tracking the index of the original partition. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to run on each partition of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each partition See Also -------- :meth:`RDD.map` :meth:`RDD.flatMap` :meth:`RDD.mapPartitions` :meth:`RDD.mapPartitionsWithSplit` :meth:`RDDBarrier.mapPartitionsWithIndex` Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 4) >>> def f(splitIndex, iterator): yield splitIndex >>> rdd.mapPartitionsWithIndex(f).sum() 6 """ return PipelinedRDD(self, f, preservesPartitioning) [docs] def mapPartitionsWithSplit( self: "RDD[T]", f: Callable[[int, Iterable[T]], Iterable[U]], preservesPartitioning: bool = False, ) -> "RDD[U]": """ Return a new RDD by applying a function to each partition of this RDD, while tracking the index of the original partition. .. versionadded:: 0.7.0 .. deprecated:: 0.9.0 use meth:`RDD.mapPartitionsWithIndex` instead. Parameters ---------- f : function a function to run on each partition of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each partition See Also -------- :meth:`RDD.map` :meth:`RDD.flatMap` :meth:`RDD.mapPartitions` :meth:`RDD.mapPartitionsWithIndex` Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 4) >>> def f(splitIndex, iterator): yield splitIndex >>> rdd.mapPartitionsWithSplit(f).sum() 6 """ warnings.warn( "mapPartitionsWithSplit is deprecated; use mapPartitionsWithIndex instead", FutureWarning, stacklevel=2, ) return self.mapPartitionsWithIndex(f, preservesPartitioning) [docs] def getNumPartitions(self) -> int: """ Returns the number of partitions in RDD .. versionadded:: 1.1.0 Returns ------- int number of partitions Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 2) >>> rdd.getNumPartitions() 2 """ return self._jrdd.partitions().size() [docs] def filter(self: "RDD[T]", f: Callable[[T], bool]) -> "RDD[T]": """ Return a new RDD containing only the elements that satisfy a predicate. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to run on each element of the RDD Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each element See Also -------- :meth:`RDD.map` Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4, 5]) >>> rdd.filter(lambda x: x % 2 == 0).collect() [2, 4] """ def func(iterator: Iterable[T]) -> Iterable[T]: return filter(fail_on_stopiteration(f), iterator) return self.mapPartitions(func, True) [docs] def distinct(self: "RDD[T]", numPartitions: Optional[int] = None) -> "RDD[T]": """ Return a new RDD containing the distinct elements in this RDD. .. versionadded:: 0.7.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a new :class:`RDD` containing the distinct elements See Also -------- :meth:`RDD.countApproxDistinct` Examples -------- >>> sorted(sc.parallelize([1, 1, 2, 3]).distinct().collect()) [1, 2, 3] """ return ( self.map(lambda x: (x, None)) .reduceByKey(lambda x, _: x, numPartitions) .map(lambda x: x[0]) ) [docs] def sample( self: "RDD[T]", withReplacement: bool, fraction: float, seed: Optional[int] = None ) -> "RDD[T]": """ Return a sampled subset of this RDD. .. versionadded:: 0.7.0 Parameters ---------- withReplacement : bool can elements be sampled multiple times (replaced when sampled out) fraction : float expected size of the sample as a fraction of this RDD's size without replacement: probability that each element is chosen; fraction must be [0, 1] with replacement: expected number of times each element is chosen; fraction must be >= 0 seed : int, optional seed for the random number generator Returns ------- :class:`RDD` a new :class:`RDD` containing a sampled subset of elements See Also -------- :meth:`RDD.takeSample` :meth:`RDD.sampleByKey` :meth:`pyspark.sql.DataFrame.sample` Notes ----- This is not guaranteed to provide exactly the fraction specified of the total count of the given :class:`DataFrame`. Examples -------- >>> rdd = sc.parallelize(range(100), 4) >>> 6 <= rdd.sample(False, 0.1, 81).count() <= 14 True """ if not fraction >= 0: raise ValueError("Fraction must be nonnegative.") return self.mapPartitionsWithIndex(RDDSampler(withReplacement, fraction, seed).func, True) [docs] def randomSplit( self: "RDD[T]", weights: Sequence[Union[int, float]], seed: Optional[int] = None ) -> "List[RDD[T]]": """ Randomly splits this RDD with the provided weights. .. versionadded:: 1.3.0 Parameters ---------- weights : list weights for splits, will be normalized if they don't sum to 1 seed : int, optional random seed Returns ------- list split :class:`RDD`\\s in a list See Also -------- :meth:`pyspark.sql.DataFrame.randomSplit` Examples -------- >>> rdd = sc.parallelize(range(500), 1) >>> rdd1, rdd2 = rdd.randomSplit([2, 3], 17) >>> len(rdd1.collect() + rdd2.collect()) 500 >>> 150 < rdd1.count() < 250 True >>> 250 < rdd2.count() < 350 True """ if not all(w >= 0 for w in weights): raise ValueError("Weights must be nonnegative") s = float(sum(weights)) if not s > 0: raise ValueError("Sum of weights must be positive") cweights = [0.0] for w in weights: cweights.append(cweights[-1] + w / s) if seed is None: seed = random.randint(0, 2**32 - 1) return [ self.mapPartitionsWithIndex(RDDRangeSampler(lb, ub, seed).func, True) for lb, ub in zip(cweights, cweights[1:]) ] # this is ported from scala/spark/RDD.scala [docs] def takeSample( self: "RDD[T]", withReplacement: bool, num: int, seed: Optional[int] = None ) -> List[T]: """ Return a fixed-size sampled subset of this RDD. .. versionadded:: 1.3.0 Parameters ---------- withReplacement : list whether sampling is done with replacement num : int size of the returned sample seed : int, optional random seed Returns ------- list a fixed-size sampled subset of this :class:`RDD` in an array See Also -------- :meth:`RDD.sample` Notes ----- This method should only be used if the resulting array is expected to be small, as all the data is loaded into the driver's memory. Examples -------- >>> import sys >>> rdd = sc.parallelize(range(0, 10)) >>> len(rdd.takeSample(True, 20, 1)) 20 >>> len(rdd.takeSample(False, 5, 2)) 5 >>> len(rdd.takeSample(False, 15, 3)) 10 >>> sc.range(0, 10).takeSample(False, sys.maxsize) Traceback (most recent call last): ... ValueError: Sample size cannot be greater than ... """ numStDev = 10.0 maxSampleSize = sys.maxsize - int(numStDev * sqrt(sys.maxsize)) if num < 0: raise ValueError("Sample size cannot be negative.") elif num > maxSampleSize: raise ValueError("Sample size cannot be greater than %d." % maxSampleSize) if num == 0 or self.getNumPartitions() == 0: return [] initialCount = self.count() if initialCount == 0: return [] rand = random.Random(seed) if (not withReplacement) and num >= initialCount: # shuffle current RDD and return samples = self.collect() rand.shuffle(samples) return samples fraction = RDD._computeFractionForSampleSize(num, initialCount, withReplacement) samples = self.sample(withReplacement, fraction, seed).collect() # If the first sample didn't turn out large enough, keep trying to take samples; # this shouldn't happen often because we use a big multiplier for their initial size. # See: scala/spark/RDD.scala while len(samples) < num: # TODO: add log warning for when more than one iteration was run seed = rand.randint(0, sys.maxsize) samples = self.sample(withReplacement, fraction, seed).collect() rand.shuffle(samples) return samples[0:num] @staticmethod def _computeFractionForSampleSize( sampleSizeLowerBound: int, total: int, withReplacement: bool ) -> float: """ Returns a sampling rate that guarantees a sample of size >= sampleSizeLowerBound 99.99% of the time. How the sampling rate is determined: Let p = num / total, where num is the sample size and total is the total number of data points in the RDD. We're trying to compute q > p such that - when sampling with replacement, we're drawing each data point with prob_i ~ Pois(q), where we want to guarantee Pr[s < num] < 0.0001 for s = sum(prob_i for i from 0 to total), i.e. the failure rate of not having a sufficiently large sample < 0.0001. Setting q = p + 5 * sqrt(p/total) is sufficient to guarantee 0.9999 success rate for num > 12, but we need a slightly larger q (9 empirically determined). - when sampling without replacement, we're drawing each data point with prob_i ~ Binomial(total, fraction) and our choice of q guarantees 1-delta, or 0.9999 success rate, where success rate is defined the same as in sampling with replacement. """ fraction = float(sampleSizeLowerBound) / total if withReplacement: numStDev = 5 if sampleSizeLowerBound < 12: numStDev = 9 return fraction + numStDev * sqrt(fraction / total) else: delta = 0.00005 gamma = -log(delta) / total return min(1, fraction + gamma + sqrt(gamma * gamma + 2 * gamma * fraction)) [docs] def union(self: "RDD[T]", other: "RDD[U]") -> "RDD[Union[T, U]]": """ Return the union of this RDD and another one. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` Returns ------- :class:`RDD` the union of this :class:`RDD` and another one See Also -------- :meth:`SparkContext.union` :meth:`pyspark.sql.DataFrame.union` Examples -------- >>> rdd = sc.parallelize([1, 1, 2, 3]) >>> rdd.union(rdd).collect() [1, 1, 2, 3, 1, 1, 2, 3] """ if self._jrdd_deserializer == other._jrdd_deserializer: rdd: "RDD[Union[T, U]]" = RDD( self._jrdd.union(other._jrdd), self.ctx, self._jrdd_deserializer ) else: # These RDDs contain data in different serialized formats, so we # must normalize them to the default serializer. self_copy = self._reserialize() other_copy = other._reserialize() rdd = RDD(self_copy._jrdd.union(other_copy._jrdd), self.ctx, self.ctx.serializer) if ( self.partitioner == other.partitioner and self.getNumPartitions() == rdd.getNumPartitions() ): rdd.partitioner = self.partitioner return rdd [docs] def intersection(self: "RDD[T]", other: "RDD[T]") -> "RDD[T]": """ Return the intersection of this RDD and another one. The output will not contain any duplicate elements, even if the input RDDs did. .. versionadded:: 1.0.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` Returns ------- :class:`RDD` the intersection of this :class:`RDD` and another one See Also -------- :meth:`pyspark.sql.DataFrame.intersect` Notes ----- This method performs a shuffle internally. Examples -------- >>> rdd1 = sc.parallelize([1, 10, 2, 3, 4, 5]) >>> rdd2 = sc.parallelize([1, 6, 2, 3, 7, 8]) >>> rdd1.intersection(rdd2).collect() [1, 2, 3] """ return ( self.map(lambda v: (v, None)) .cogroup(other.map(lambda v: (v, None))) .filter(lambda k_vs: all(k_vs[1])) .keys() ) def _reserialize(self: "RDD[T]", serializer: Optional[Serializer] = None) -> "RDD[T]": serializer = serializer or self.ctx.serializer if self._jrdd_deserializer != serializer: self = self.map(lambda x: x, preservesPartitioning=True) self._jrdd_deserializer = serializer return self def __add__(self: "RDD[T]", other: "RDD[U]") -> "RDD[Union[T, U]]": """ Return the union of this RDD and another one. Examples -------- >>> rdd = sc.parallelize([1, 1, 2, 3]) >>> (rdd + rdd).collect() [1, 1, 2, 3, 1, 1, 2, 3] """ if not isinstance(other, RDD): raise TypeError return self.union(other) @overload def repartitionAndSortWithinPartitions( self: "RDD[Tuple[S, V]]", numPartitions: Optional[int] = ..., partitionFunc: Callable[["S"], int] = ..., ascending: bool = ..., ) -> "RDD[Tuple[S, V]]": ... @overload def repartitionAndSortWithinPartitions( self: "RDD[Tuple[K, V]]", numPartitions: Optional[int], partitionFunc: Callable[[K], int], ascending: bool, keyfunc: Callable[[K], "S"], ) -> "RDD[Tuple[K, V]]": ... @overload def repartitionAndSortWithinPartitions( self: "RDD[Tuple[K, V]]", numPartitions: Optional[int] = ..., partitionFunc: Callable[[K], int] = ..., ascending: bool = ..., *, keyfunc: Callable[[K], "S"], ) -> "RDD[Tuple[K, V]]": ... [docs] def repartitionAndSortWithinPartitions( self: "RDD[Tuple[Any, Any]]", numPartitions: Optional[int] = None, partitionFunc: Callable[[Any], int] = portable_hash, ascending: bool = True, keyfunc: Callable[[Any], Any] = lambda x: x, ) -> "RDD[Tuple[Any, Any]]": """ Repartition the RDD according to the given partitioner and, within each resulting partition, sort records by their keys. .. versionadded:: 1.2.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` a function to compute the partition index ascending : bool, optional, default True sort the keys in ascending or descending order keyfunc : function, optional, default identity mapping a function to compute the key Returns ------- :class:`RDD` a new :class:`RDD` See Also -------- :meth:`RDD.repartition` :meth:`RDD.partitionBy` :meth:`RDD.sortBy` :meth:`RDD.sortByKey` Examples -------- >>> rdd = sc.parallelize([(0, 5), (3, 8), (2, 6), (0, 8), (3, 8), (1, 3)]) >>> rdd2 = rdd.repartitionAndSortWithinPartitions(2, lambda x: x % 2, True) >>> rdd2.glom().collect() [[(0, 5), (0, 8), (2, 6)], [(1, 3), (3, 8), (3, 8)]] """ if numPartitions is None: numPartitions = self._defaultReducePartitions() memory = self._memory_limit() serializer = self._jrdd_deserializer def sortPartition(iterator: Iterable[Tuple[K, V]]) -> Iterable[Tuple[K, V]]: sort = ExternalSorter(memory * 0.9, serializer).sorted return iter(sort(iterator, key=lambda k_v: keyfunc(k_v[0]), reverse=(not ascending))) return self.partitionBy(numPartitions, partitionFunc).mapPartitions(sortPartition, True) @overload def sortByKey( self: "RDD[Tuple[S, V]]", ascending: bool = ..., numPartitions: Optional[int] = ..., ) -> "RDD[Tuple[K, V]]": ... @overload def sortByKey( self: "RDD[Tuple[K, V]]", ascending: bool, numPartitions: int, keyfunc: Callable[[K], "S"], ) -> "RDD[Tuple[K, V]]": ... @overload def sortByKey( self: "RDD[Tuple[K, V]]", ascending: bool = ..., numPartitions: Optional[int] = ..., *, keyfunc: Callable[[K], "S"], ) -> "RDD[Tuple[K, V]]": ... [docs] def sortByKey( self: "RDD[Tuple[K, V]]", ascending: Optional[bool] = True, numPartitions: Optional[int] = None, keyfunc: Callable[[Any], Any] = lambda x: x, ) -> "RDD[Tuple[K, V]]": """ Sorts this RDD, which is assumed to consist of (key, value) pairs. .. versionadded:: 0.9.1 Parameters ---------- ascending : bool, optional, default True sort the keys in ascending or descending order numPartitions : int, optional the number of partitions in new :class:`RDD` keyfunc : function, optional, default identity mapping a function to compute the key Returns ------- :class:`RDD` a new :class:`RDD` See Also -------- :meth:`RDD.sortBy` :meth:`pyspark.sql.DataFrame.sort` Examples -------- >>> tmp = [('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)] >>> sc.parallelize(tmp).sortByKey().first() ('1', 3) >>> sc.parallelize(tmp).sortByKey(True, 1).collect() [('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)] >>> sc.parallelize(tmp).sortByKey(True, 2).collect() [('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)] >>> tmp2 = [('Mary', 1), ('had', 2), ('a', 3), ('little', 4), ('lamb', 5)] >>> tmp2.extend([('whose', 6), ('fleece', 7), ('was', 8), ('white', 9)]) >>> sc.parallelize(tmp2).sortByKey(True, 3, keyfunc=lambda k: k.lower()).collect() [('a', 3), ('fleece', 7), ('had', 2), ('lamb', 5),...('white', 9), ('whose', 6)] """ if numPartitions is None: numPartitions = self._defaultReducePartitions() memory = self._memory_limit() serializer = self._jrdd_deserializer def sortPartition(iterator: Iterable[Tuple[K, V]]) -> Iterable[Tuple[K, V]]: sort = ExternalSorter(memory * 0.9, serializer).sorted return iter(sort(iterator, key=lambda kv: keyfunc(kv[0]), reverse=(not ascending))) if numPartitions == 1: if self.getNumPartitions() > 1: self = self.coalesce(1) return self.mapPartitions(sortPartition, True) # first compute the boundary of each part via sampling: we want to partition # the key-space into bins such that the bins have roughly the same # number of (key, value) pairs falling into them rddSize = self.count() if not rddSize: return self # empty RDD maxSampleSize = numPartitions * 20.0 # constant from Spark's RangePartitioner fraction = min(maxSampleSize / max(rddSize, 1), 1.0) samples = self.sample(False, fraction, 1).map(lambda kv: kv[0]).collect() samples = sorted(samples, key=keyfunc) # we have numPartitions many parts but one of the them has # an implicit boundary bounds = [ samples[int(len(samples) * (i + 1) / numPartitions)] for i in range(0, numPartitions - 1) ] def rangePartitioner(k: K) -> int: p = bisect.bisect_left(bounds, keyfunc(k)) if ascending: return p else: return numPartitions - 1 - p # type: ignore[operator] return self.partitionBy(numPartitions, rangePartitioner).mapPartitions(sortPartition, True) [docs] def sortBy( self: "RDD[T]", keyfunc: Callable[[T], "S"], ascending: bool = True, numPartitions: Optional[int] = None, ) -> "RDD[T]": """ Sorts this RDD by the given keyfunc .. versionadded:: 1.1.0 Parameters ---------- keyfunc : function a function to compute the key ascending : bool, optional, default True sort the keys in ascending or descending order numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a new :class:`RDD` See Also -------- :meth:`RDD.sortByKey` :meth:`pyspark.sql.DataFrame.sort` Examples -------- >>> tmp = [('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)] >>> sc.parallelize(tmp).sortBy(lambda x: x[0]).collect() [('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)] >>> sc.parallelize(tmp).sortBy(lambda x: x[1]).collect() [('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)] """ return ( self.keyBy(keyfunc) # type: ignore[type-var] .sortByKey(ascending, numPartitions) .values() ) [docs] def glom(self: "RDD[T]") -> "RDD[List[T]]": """ Return an RDD created by coalescing all elements within each partition into a list. .. versionadded:: 0.7.0 Returns ------- :class:`RDD` a new :class:`RDD` coalescing all elements within each partition into a list Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 2) >>> sorted(rdd.glom().collect()) [[1, 2], [3, 4]] """ def func(iterator: Iterable[T]) -> Iterable[List[T]]: yield list(iterator) return self.mapPartitions(func) [docs] def cartesian(self: "RDD[T]", other: "RDD[U]") -> "RDD[Tuple[T, U]]": """ Return the Cartesian product of this RDD and another one, that is, the RDD of all pairs of elements ``(a, b)`` where ``a`` is in `self` and ``b`` is in `other`. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` Returns ------- :class:`RDD` the Cartesian product of this :class:`RDD` and another one See Also -------- :meth:`pyspark.sql.DataFrame.crossJoin` Examples -------- >>> rdd = sc.parallelize([1, 2]) >>> sorted(rdd.cartesian(rdd).collect()) [(1, 1), (1, 2), (2, 1), (2, 2)] """ # Due to batching, we can't use the Java cartesian method. deserializer = CartesianDeserializer(self._jrdd_deserializer, other._jrdd_deserializer) return RDD(self._jrdd.cartesian(other._jrdd), self.ctx, deserializer) [docs] def groupBy( self: "RDD[T]", f: Callable[[T], K], numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, Iterable[T]]]": """ Return an RDD of grouped items. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to compute the key numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` a function to compute the partition index Returns ------- :class:`RDD` a new :class:`RDD` of grouped items See Also -------- :meth:`RDD.groupByKey` :meth:`pyspark.sql.DataFrame.groupBy` Examples -------- >>> rdd = sc.parallelize([1, 1, 2, 3, 5, 8]) >>> result = rdd.groupBy(lambda x: x % 2).collect() >>> sorted([(x, sorted(y)) for (x, y) in result]) [(0, [2, 8]), (1, [1, 1, 3, 5])] """ return self.map(lambda x: (f(x), x)).groupByKey(numPartitions, partitionFunc) [docs] def pipe( self, command: str, env: Optional[Dict[str, str]] = None, checkCode: bool = False ) -> "RDD[str]": """ Return an RDD created by piping elements to a forked external process. .. versionadded:: 0.7.0 Parameters ---------- command : str command to run. env : dict, optional environment variables to set. checkCode : bool, optional whether to check the return value of the shell command. Returns ------- :class:`RDD` a new :class:`RDD` of strings Examples -------- >>> sc.parallelize(['1', '2', '', '3']).pipe('cat').collect() ['1', '2', '', '3'] """ if env is None: env = dict() def func(iterator: Iterable[T]) -> Iterable[str]: pipe = Popen(shlex.split(command), env=env, stdin=PIPE, stdout=PIPE) def pipe_objs(out: IO[bytes]) -> None: for obj in iterator: s = str(obj).rstrip("\n") + "\n" out.write(s.encode("utf-8")) out.close() Thread(target=pipe_objs, args=[pipe.stdin]).start() def check_return_code() -> Iterable[int]: pipe.wait() if checkCode and pipe.returncode: raise RuntimeError( "Pipe function `%s' exited " "with error code %d" % (command, pipe.returncode) ) else: for i in range(0): yield i return ( cast(bytes, x).rstrip(b"\n").decode("utf-8") for x in chain( iter(cast(IO[bytes], pipe.stdout).readline, b""), check_return_code() ) ) return self.mapPartitions(func) [docs] def foreach(self: "RDD[T]", f: Callable[[T], None]) -> None: """ Applies a function to all elements of this RDD. .. versionadded:: 0.7.0 Parameters ---------- f : function a function applyed to each element See Also -------- :meth:`RDD.foreachPartition` :meth:`pyspark.sql.DataFrame.foreach` :meth:`pyspark.sql.DataFrame.foreachPartition` Examples -------- >>> def f(x): print(x) >>> sc.parallelize([1, 2, 3, 4, 5]).foreach(f) """ f = fail_on_stopiteration(f) def processPartition(iterator: Iterable[T]) -> Iterable[Any]: for x in iterator: f(x) return iter([]) self.mapPartitions(processPartition).count() # Force evaluation [docs] def foreachPartition(self: "RDD[T]", f: Callable[[Iterable[T]], None]) -> None: """ Applies a function to each partition of this RDD. .. versionadded:: 1.0.0 Parameters ---------- f : function a function applied to each partition See Also -------- :meth:`RDD.foreach` :meth:`pyspark.sql.DataFrame.foreach` :meth:`pyspark.sql.DataFrame.foreachPartition` Examples -------- >>> def f(iterator): ... for x in iterator: ... print(x) >>> sc.parallelize([1, 2, 3, 4, 5]).foreachPartition(f) """ def func(it: Iterable[T]) -> Iterable[Any]: r = f(it) try: return iter(r) # type: ignore[call-overload] except TypeError: return iter([]) self.mapPartitions(func).count() # Force evaluation [docs] def collect(self: "RDD[T]") -> List[T]: """ Return a list that contains all the elements in this RDD. .. versionadded:: 0.7.0 Returns ------- list a list containing all the elements Notes ----- This method should only be used if the resulting array is expected to be small, as all the data is loaded into the driver's memory. See Also -------- :meth:`RDD.toLocalIterator` :meth:`pyspark.sql.DataFrame.collect` Examples -------- >>> sc.range(5).collect() [0, 1, 2, 3, 4] >>> sc.parallelize(["x", "y", "z"]).collect() ['x', 'y', 'z'] """ with SCCallSiteSync(self.context): assert self.ctx._jvm is not None sock_info = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd()) return list(_load_from_socket(sock_info, self._jrdd_deserializer)) [docs] def collectWithJobGroup( self: "RDD[T]", groupId: str, description: str, interruptOnCancel: bool = False ) -> "List[T]": """ When collect rdd, use this method to specify job group. .. versionadded:: 3.0.0 .. deprecated:: 3.1.0 Use :class:`pyspark.InheritableThread` with the pinned thread mode enabled. Parameters ---------- groupId : str The group ID to assign. description : str The description to set for the job group. interruptOnCancel : bool, optional, default False whether to interrupt jobs on job cancellation. Returns ------- list a list containing all the elements See Also -------- :meth:`RDD.collect` :meth:`SparkContext.setJobGroup` """ warnings.warn( "Deprecated in 3.1, Use pyspark.InheritableThread with " "the pinned thread mode enabled.", FutureWarning, ) with SCCallSiteSync(self.context): assert self.ctx._jvm is not None sock_info = self.ctx._jvm.PythonRDD.collectAndServeWithJobGroup( self._jrdd.rdd(), groupId, description, interruptOnCancel ) return list(_load_from_socket(sock_info, self._jrdd_deserializer)) [docs] def reduce(self: "RDD[T]", f: Callable[[T, T], T]) -> T: """ Reduces the elements of this RDD using the specified commutative and associative binary operator. Currently reduces partitions locally. .. versionadded:: 0.7.0 Parameters ---------- f : function the reduce function Returns ------- T the aggregated result See Also -------- :meth:`RDD.treeReduce` :meth:`RDD.aggregate` :meth:`RDD.treeAggregate` Examples -------- >>> from operator import add >>> sc.parallelize([1, 2, 3, 4, 5]).reduce(add) 15 >>> sc.parallelize((2 for _ in range(10))).map(lambda x: 1).cache().reduce(add) 10 >>> sc.parallelize([]).reduce(add) Traceback (most recent call last): ... ValueError: Can not reduce() empty RDD """ f = fail_on_stopiteration(f) def func(iterator: Iterable[T]) -> Iterable[T]: iterator = iter(iterator) try: initial = next(iterator) except StopIteration: return yield reduce(f, iterator, initial) vals = self.mapPartitions(func).collect() if vals: return reduce(f, vals) raise ValueError("Can not reduce() empty RDD") [docs] def treeReduce(self: "RDD[T]", f: Callable[[T, T], T], depth: int = 2) -> T: """ Reduces the elements of this RDD in a multi-level tree pattern. .. versionadded:: 1.3.0 Parameters ---------- f : function the reduce function depth : int, optional, default 2 suggested depth of the tree (default: 2) Returns ------- T the aggregated result See Also -------- :meth:`RDD.reduce` :meth:`RDD.aggregate` :meth:`RDD.treeAggregate` Examples -------- >>> add = lambda x, y: x + y >>> rdd = sc.parallelize([-5, -4, -3, -2, -1, 1, 2, 3, 4], 10) >>> rdd.treeReduce(add) -5 >>> rdd.treeReduce(add, 1) -5 >>> rdd.treeReduce(add, 2) -5 >>> rdd.treeReduce(add, 5) -5 >>> rdd.treeReduce(add, 10) -5 """ if depth < 1: raise ValueError("Depth cannot be smaller than 1 but got %d." % depth) # Use the second entry to indicate whether this is a dummy value. zeroValue: Tuple[T, bool] = ( # type: ignore[assignment] None, True, ) def op(x: Tuple[T, bool], y: Tuple[T, bool]) -> Tuple[T, bool]: if x[1]: return y elif y[1]: return x else: return f(x[0], y[0]), False reduced = self.map(lambda x: (x, False)).treeAggregate(zeroValue, op, op, depth) if reduced[1]: raise ValueError("Cannot reduce empty RDD.") return reduced[0] [docs] def fold(self: "RDD[T]", zeroValue: T, op: Callable[[T, T], T]) -> T: """ Aggregate the elements of each partition, and then the results for all the partitions, using a given associative function and a neutral "zero value." The function ``op(t1, t2)`` is allowed to modify ``t1`` and return it as its result value to avoid object allocation; however, it should not modify ``t2``. This behaves somewhat differently from fold operations implemented for non-distributed collections in functional languages like Scala. This fold operation may be applied to partitions individually, and then fold those results into the final result, rather than apply the fold to each element sequentially in some defined ordering. For functions that are not commutative, the result may differ from that of a fold applied to a non-distributed collection. .. versionadded:: 0.7.0 Parameters ---------- zeroValue : T the initial value for the accumulated result of each partition op : function a function used to both accumulate results within a partition and combine results from different partitions Returns ------- T the aggregated result See Also -------- :meth:`RDD.reduce` :meth:`RDD.aggregate` Examples -------- >>> from operator import add >>> sc.parallelize([1, 2, 3, 4, 5]).fold(0, add) 15 """ op = fail_on_stopiteration(op) def func(iterator: Iterable[T]) -> Iterable[T]: acc = zeroValue for obj in iterator: acc = op(acc, obj) yield acc # collecting result of mapPartitions here ensures that the copy of # zeroValue provided to each partition is unique from the one provided # to the final reduce call vals = self.mapPartitions(func).collect() return reduce(op, vals, zeroValue) [docs] def aggregate( self: "RDD[T]", zeroValue: U, seqOp: Callable[[U, T], U], combOp: Callable[[U, U], U] ) -> U: """ Aggregate the elements of each partition, and then the results for all the partitions, using a given combine functions and a neutral "zero value." The functions ``op(t1, t2)`` is allowed to modify ``t1`` and return it as its result value to avoid object allocation; however, it should not modify ``t2``. The first function (seqOp) can return a different result type, U, than the type of this RDD. Thus, we need one operation for merging a T into an U and one operation for merging two U .. versionadded:: 1.1.0 Parameters ---------- zeroValue : U the initial value for the accumulated result of each partition seqOp : function a function used to accumulate results within a partition combOp : function an associative function used to combine results from different partitions Returns ------- U the aggregated result See Also -------- :meth:`RDD.reduce` :meth:`RDD.fold` Examples -------- >>> seqOp = (lambda x, y: (x[0] + y, x[1] + 1)) >>> combOp = (lambda x, y: (x[0] + y[0], x[1] + y[1])) >>> sc.parallelize([1, 2, 3, 4]).aggregate((0, 0), seqOp, combOp) (10, 4) >>> sc.parallelize([]).aggregate((0, 0), seqOp, combOp) (0, 0) """ seqOp = fail_on_stopiteration(seqOp) combOp = fail_on_stopiteration(combOp) def func(iterator: Iterable[T]) -> Iterable[U]: acc = zeroValue for obj in iterator: acc = seqOp(acc, obj) yield acc # collecting result of mapPartitions here ensures that the copy of # zeroValue provided to each partition is unique from the one provided # to the final reduce call vals = self.mapPartitions(func).collect() return reduce(combOp, vals, zeroValue) [docs] def treeAggregate( self: "RDD[T]", zeroValue: U, seqOp: Callable[[U, T], U], combOp: Callable[[U, U], U], depth: int = 2, ) -> U: """ Aggregates the elements of this RDD in a multi-level tree pattern. .. versionadded:: 1.3.0 Parameters ---------- zeroValue : U the initial value for the accumulated result of each partition seqOp : function a function used to accumulate results within a partition combOp : function an associative function used to combine results from different partitions depth : int, optional, default 2 suggested depth of the tree Returns ------- U the aggregated result See Also -------- :meth:`RDD.aggregate` :meth:`RDD.treeReduce` Examples -------- >>> add = lambda x, y: x + y >>> rdd = sc.parallelize([-5, -4, -3, -2, -1, 1, 2, 3, 4], 10) >>> rdd.treeAggregate(0, add, add) -5 >>> rdd.treeAggregate(0, add, add, 1) -5 >>> rdd.treeAggregate(0, add, add, 2) -5 >>> rdd.treeAggregate(0, add, add, 5) -5 >>> rdd.treeAggregate(0, add, add, 10) -5 """ if depth < 1: raise ValueError("Depth cannot be smaller than 1 but got %d." % depth) if self.getNumPartitions() == 0: return zeroValue def aggregatePartition(iterator: Iterable[T]) -> Iterable[U]: acc = zeroValue for obj in iterator: acc = seqOp(acc, obj) yield acc partiallyAggregated = self.mapPartitions(aggregatePartition) numPartitions = partiallyAggregated.getNumPartitions() scale = max(int(ceil(pow(numPartitions, 1.0 / depth))), 2) # If creating an extra level doesn't help reduce the wall-clock time, we stop the tree # aggregation. while numPartitions > scale + numPartitions / scale: numPartitions /= scale # type: ignore[assignment] curNumPartitions = int(numPartitions) def mapPartition(i: int, iterator: Iterable[U]) -> Iterable[Tuple[int, U]]: for obj in iterator: yield (i % curNumPartitions, obj) partiallyAggregated = ( partiallyAggregated.mapPartitionsWithIndex(mapPartition) .reduceByKey(combOp, curNumPartitions) .values() ) return partiallyAggregated.reduce(combOp) @overload def max(self: "RDD[S]") -> "S": ... @overload def max(self: "RDD[T]", key: Callable[[T], "S"]) -> T: ... [docs] def max(self: "RDD[T]", key: Optional[Callable[[T], "S"]] = None) -> T: """ Find the maximum item in this RDD. .. versionadded:: 1.0.0 Parameters ---------- key : function, optional A function used to generate key for comparing Returns ------- T the maximum item See Also -------- :meth:`RDD.min` Examples -------- >>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0]) >>> rdd.max() 43.0 >>> rdd.max(key=str) 5.0 """ if key is None: return self.reduce(max) # type: ignore[arg-type] return self.reduce(lambda a, b: max(a, b, key=key)) # type: ignore[arg-type] @overload def min(self: "RDD[S]") -> "S": ... @overload def min(self: "RDD[T]", key: Callable[[T], "S"]) -> T: ... [docs] def min(self: "RDD[T]", key: Optional[Callable[[T], "S"]] = None) -> T: """ Find the minimum item in this RDD. .. versionadded:: 1.0.0 Parameters ---------- key : function, optional A function used to generate key for comparing Returns ------- T the minimum item See Also -------- :meth:`RDD.max` Examples -------- >>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0]) >>> rdd.min() 2.0 >>> rdd.min(key=str) 10.0 """ if key is None: return self.reduce(min) # type: ignore[arg-type] return self.reduce(lambda a, b: min(a, b, key=key)) # type: ignore[arg-type] [docs] def sum(self: "RDD[NumberOrArray]") -> "NumberOrArray": """ Add up the elements in this RDD. .. versionadded:: 0.7.0 Returns ------- float, int, or complex the sum of all elements See Also -------- :meth:`RDD.mean` :meth:`RDD.sumApprox` Examples -------- >>> sc.parallelize([1.0, 2.0, 3.0]).sum() 6.0 """ return self.mapPartitions(lambda x: [sum(x)]).fold( # type: ignore[return-value] 0, operator.add ) [docs] def count(self) -> int: """ Return the number of elements in this RDD. .. versionadded:: 0.7.0 Returns ------- int the number of elements See Also -------- :meth:`RDD.countApprox` :meth:`pyspark.sql.DataFrame.count` Examples -------- >>> sc.parallelize([2, 3, 4]).count() 3 """ return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum() [docs] def stats(self: "RDD[NumberOrArray]") -> StatCounter: """ Return a :class:`StatCounter` object that captures the mean, variance and count of the RDD's elements in one operation. .. versionadded:: 0.9.1 Returns ------- :class:`StatCounter` a :class:`StatCounter` capturing the mean, variance and count of all elements See Also -------- :meth:`RDD.stdev` :meth:`RDD.sampleStdev` :meth:`RDD.variance` :meth:`RDD.sampleVariance` :meth:`RDD.histogram` :meth:`pyspark.sql.DataFrame.stat` """ def redFunc(left_counter: StatCounter, right_counter: StatCounter) -> StatCounter: return left_counter.mergeStats(right_counter) return self.mapPartitions(lambda i: [StatCounter(i)]).reduce( # type: ignore[arg-type] redFunc ) [docs] def histogram( self: "RDD[S]", buckets: Union[int, List["S"], Tuple["S", ...]] ) -> Tuple[Sequence["S"], List[int]]: """ Compute a histogram using the provided buckets. The buckets are all open to the right except for the last which is closed. e.g. [1,10,20,50] means the buckets are [1,10) [10,20) [20,50], which means 1<=x<10, 10<=x<20, 20<=x<=50. And on the input of 1 and 50 we would have a histogram of 1,0,1. If your histogram is evenly spaced (e.g. [0, 10, 20, 30]), this can be switched from an O(log n) insertion to O(1) per element (where n is the number of buckets). Buckets must be sorted, not contain any duplicates, and have at least two elements. If `buckets` is a number, it will generate buckets which are evenly spaced between the minimum and maximum of the RDD. For example, if the min value is 0 and the max is 100, given `buckets` as 2, the resulting buckets will be [0,50) [50,100]. `buckets` must be at least 1. An exception is raised if the RDD contains infinity. If the elements in the RDD do not vary (max == min), a single bucket will be used. .. versionadded:: 1.2.0 Parameters ---------- buckets : int, or list, or tuple if `buckets` is a number, it computes a histogram of the data using `buckets` number of buckets evenly, otherwise, `buckets` is the provided buckets to bin the data. Returns ------- tuple a tuple of buckets and histogram See Also -------- :meth:`RDD.stats` Examples -------- >>> rdd = sc.parallelize(range(51)) >>> rdd.histogram(2) ([0, 25, 50], [25, 26]) >>> rdd.histogram([0, 5, 25, 50]) ([0, 5, 25, 50], [5, 20, 26]) >>> rdd.histogram([0, 15, 30, 45, 60]) # evenly spaced buckets ([0, 15, 30, 45, 60], [15, 15, 15, 6]) >>> rdd = sc.parallelize(["ab", "ac", "b", "bd", "ef"]) >>> rdd.histogram(("a", "b", "c")) (('a', 'b', 'c'), [2, 2]) """ if isinstance(buckets, int): if buckets < 1: raise ValueError("number of buckets must be >= 1") # filter out non-comparable elements def comparable(x: Any) -> bool: if x is None: return False if type(x) is float and isnan(x): return False return True filtered = self.filter(comparable) # faster than stats() def minmax(a: Tuple["S", "S"], b: Tuple["S", "S"]) -> Tuple["S", "S"]: return min(a[0], b[0]), max(a[1], b[1]) try: minv, maxv = filtered.map(lambda x: (x, x)).reduce(minmax) except TypeError as e: if " empty " in str(e): raise ValueError("can not generate buckets from empty RDD") raise if minv == maxv or buckets == 1: return [minv, maxv], [filtered.count()] try: inc = (maxv - minv) / buckets # type: ignore[operator] except TypeError: raise TypeError("Can not generate buckets with non-number in RDD") if isinf(inc): raise ValueError("Can not generate buckets with infinite value") # keep them as integer if possible inc = int(inc) if inc * buckets != maxv - minv: # type: ignore[operator] inc = (maxv - minv) * 1.0 / buckets # type: ignore[operator] buckets = [i * inc + minv for i in range(buckets)] buckets.append(maxv) # fix accumulated error even = True elif isinstance(buckets, (list, tuple)): if len(buckets) < 2: raise ValueError("buckets should have more than one value") if any(i is None or isinstance(i, float) and isnan(i) for i in buckets): raise ValueError("can not have None or NaN in buckets") if sorted(buckets) != list(buckets): raise ValueError("buckets should be sorted") if len(set(buckets)) != len(buckets): raise ValueError("buckets should not contain duplicated values") minv = buckets[0] maxv = buckets[-1] even = False inc = None try: steps = [ buckets[i + 1] - buckets[i] # type: ignore[operator] for i in range(len(buckets) - 1) ] except TypeError: pass # objects in buckets do not support '-' else: if max(steps) - min(steps) < 1e-10: # handle precision errors even = True inc = (maxv - minv) / (len(buckets) - 1) # type: ignore[operator] else: raise TypeError("buckets should be a list or tuple or number(int or long)") def histogram(iterator: Iterable["S"]) -> Iterable[List[int]]: counters = [0] * len(buckets) # type: ignore[arg-type] for i in iterator: if i is None or (isinstance(i, float) and isnan(i)) or i > maxv or i < minv: continue t = ( int((i - minv) / inc) # type: ignore[operator] if even else bisect.bisect_right(buckets, i) - 1 # type: ignore[arg-type] ) counters[t] += 1 # add last two together last = counters.pop() counters[-1] += last return [counters] def mergeCounters(a: List[int], b: List[int]) -> List[int]: return [i + j for i, j in zip(a, b)] return buckets, self.mapPartitions(histogram).reduce(mergeCounters) [docs] def mean(self: "RDD[NumberOrArray]") -> float: """ Compute the mean of this RDD's elements. .. versionadded:: 0.9.1 Returns ------- float the mean of all elements See Also -------- :meth:`RDD.stats` :meth:`RDD.sum` :meth:`RDD.meanApprox` Examples -------- >>> sc.parallelize([1, 2, 3]).mean() 2.0 """ return self.stats().mean() [docs] def variance(self: "RDD[NumberOrArray]") -> float: """ Compute the variance of this RDD's elements. .. versionadded:: 0.9.1 Returns ------- float the variance of all elements See Also -------- :meth:`RDD.stats` :meth:`RDD.sampleVariance` :meth:`RDD.stdev` :meth:`RDD.sampleStdev` Examples -------- >>> sc.parallelize([1, 2, 3]).variance() 0.666... """ return self.stats().variance() [docs] def stdev(self: "RDD[NumberOrArray]") -> float: """ Compute the standard deviation of this RDD's elements. .. versionadded:: 0.9.1 Returns ------- float the standard deviation of all elements See Also -------- :meth:`RDD.stats` :meth:`RDD.sampleStdev` :meth:`RDD.variance` :meth:`RDD.sampleVariance` Examples -------- >>> sc.parallelize([1, 2, 3]).stdev() 0.816... """ return self.stats().stdev() [docs] def sampleStdev(self: "RDD[NumberOrArray]") -> float: """ Compute the sample standard deviation of this RDD's elements (which corrects for bias in estimating the standard deviation by dividing by N-1 instead of N). .. versionadded:: 0.9.1 Returns ------- float the sample standard deviation of all elements See Also -------- :meth:`RDD.stats` :meth:`RDD.stdev` :meth:`RDD.variance` :meth:`RDD.sampleVariance` Examples -------- >>> sc.parallelize([1, 2, 3]).sampleStdev() 1.0 """ return self.stats().sampleStdev() [docs] def sampleVariance(self: "RDD[NumberOrArray]") -> float: """ Compute the sample variance of this RDD's elements (which corrects for bias in estimating the variance by dividing by N-1 instead of N). .. versionadded:: 0.9.1 Returns ------- float the sample variance of all elements See Also -------- :meth:`RDD.stats` :meth:`RDD.variance` :meth:`RDD.stdev` :meth:`RDD.sampleStdev` Examples -------- >>> sc.parallelize([1, 2, 3]).sampleVariance() 1.0 """ return self.stats().sampleVariance() [docs] def countByValue(self: "RDD[K]") -> Dict[K, int]: """ Return the count of each unique value in this RDD as a dictionary of (value, count) pairs. .. versionadded:: 0.7.0 Returns ------- dict a dictionary of (value, count) pairs See Also -------- :meth:`RDD.collectAsMap` :meth:`RDD.countByKey` Examples -------- >>> sorted(sc.parallelize([1, 2, 1, 2, 2], 2).countByValue().items()) [(1, 2), (2, 3)] """ def countPartition(iterator: Iterable[K]) -> Iterable[Dict[K, int]]: counts: Dict[K, int] = defaultdict(int) for obj in iterator: counts[obj] += 1 yield counts def mergeMaps(m1: Dict[K, int], m2: Dict[K, int]) -> Dict[K, int]: for k, v in m2.items(): m1[k] += v return m1 return self.mapPartitions(countPartition).reduce(mergeMaps) @overload def top(self: "RDD[S]", num: int) -> List["S"]: ... @overload def top(self: "RDD[T]", num: int, key: Callable[[T], "S"]) -> List[T]: ... [docs] def top(self: "RDD[T]", num: int, key: Optional[Callable[[T], "S"]] = None) -> List[T]: """ Get the top N elements from an RDD. .. versionadded:: 1.0.0 Parameters ---------- num : int top N key : function, optional a function used to generate key for comparing Returns ------- list the top N elements See Also -------- :meth:`RDD.takeOrdered` :meth:`RDD.max` :meth:`RDD.min` Notes ----- This method should only be used if the resulting array is expected to be small, as all the data is loaded into the driver's memory. It returns the list sorted in descending order. Examples -------- >>> sc.parallelize([10, 4, 2, 12, 3]).top(1) [12] >>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2) [6, 5] >>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str) [4, 3, 2] """ def topIterator(iterator: Iterable[T]) -> Iterable[List[T]]: yield heapq.nlargest(num, iterator, key=key) def merge(a: List[T], b: List[T]) -> List[T]: return heapq.nlargest(num, a + b, key=key) return self.mapPartitions(topIterator).reduce(merge) @overload def takeOrdered(self: "RDD[S]", num: int) -> List["S"]: ... @overload def takeOrdered(self: "RDD[T]", num: int, key: Callable[[T], "S"]) -> List[T]: ... [docs] def takeOrdered(self: "RDD[T]", num: int, key: Optional[Callable[[T], "S"]] = None) -> List[T]: """ Get the N elements from an RDD ordered in ascending order or as specified by the optional key function. .. versionadded:: 1.0.0 Parameters ---------- num : int top N key : function, optional a function used to generate key for comparing Returns ------- list the top N elements See Also -------- :meth:`RDD.top` :meth:`RDD.max` :meth:`RDD.min` Notes ----- This method should only be used if the resulting array is expected to be small, as all the data is loaded into the driver's memory. Examples -------- >>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7]).takeOrdered(6) [1, 2, 3, 4, 5, 6] >>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7], 2).takeOrdered(6, key=lambda x: -x) [10, 9, 7, 6, 5, 4] >>> sc.emptyRDD().takeOrdered(3) [] """ if num < 0: raise ValueError("top N cannot be negative.") if num == 0 or self.getNumPartitions() == 0: return [] else: def merge(a: List[T], b: List[T]) -> List[T]: return heapq.nsmallest(num, a + b, key) return self.mapPartitions(lambda it: [heapq.nsmallest(num, it, key)]).reduce(merge) [docs] def take(self: "RDD[T]", num: int) -> List[T]: """ Take the first num elements of the RDD. It works by first scanning one partition, and use the results from that partition to estimate the number of additional partitions needed to satisfy the limit. Translated from the Scala implementation in RDD#take(). .. versionadded:: 0.7.0 Parameters ---------- num : int first number of elements Returns ------- list the first `num` elements See Also -------- :meth:`RDD.first` :meth:`pyspark.sql.DataFrame.take` Notes ----- This method should only be used if the resulting array is expected to be small, as all the data is loaded into the driver's memory. Examples -------- >>> sc.parallelize([2, 3, 4, 5, 6]).cache().take(2) [2, 3] >>> sc.parallelize([2, 3, 4, 5, 6]).take(10) [2, 3, 4, 5, 6] >>> sc.parallelize(range(100), 100).filter(lambda x: x > 90).take(3) [91, 92, 93] """ items: List[T] = [] totalParts = self.getNumPartitions() partsScanned = 0 while len(items) < num and partsScanned < totalParts: # The number of partitions to try in this iteration. # It is ok for this number to be greater than totalParts because # we actually cap it at totalParts in runJob. numPartsToTry = 1 if partsScanned > 0: # If we didn't find any rows after the previous iteration, # quadruple and retry. Otherwise, interpolate the number of # partitions we need to try, but overestimate it by 50%. # We also cap the estimation in the end. if len(items) == 0: numPartsToTry = partsScanned * 4 else: # the first parameter of max is >=1 whenever partsScanned >= 2 numPartsToTry = int(1.5 * num * partsScanned / len(items)) - partsScanned numPartsToTry = min(max(numPartsToTry, 1), partsScanned * 4) left = num - len(items) def takeUpToNumLeft(iterator: Iterable[T]) -> Iterable[T]: iterator = iter(iterator) taken = 0 while taken < left: try: yield next(iterator) except StopIteration: return taken += 1 p = range(partsScanned, min(partsScanned + numPartsToTry, totalParts)) res = self.context.runJob(self, takeUpToNumLeft, p) items += res partsScanned += numPartsToTry return items[:num] [docs] def first(self: "RDD[T]") -> T: """ Return the first element in this RDD. .. versionadded:: 0.7.0 Returns ------- T the first element See Also -------- :meth:`RDD.take` :meth:`pyspark.sql.DataFrame.first` :meth:`pyspark.sql.DataFrame.head` Examples -------- >>> sc.parallelize([2, 3, 4]).first() 2 >>> sc.parallelize([]).first() Traceback (most recent call last): ... ValueError: RDD is empty """ rs = self.take(1) if rs: return rs[0] raise ValueError("RDD is empty") [docs] def isEmpty(self) -> bool: """ Returns true if and only if the RDD contains no elements at all. .. versionadded:: 1.3.0 Returns ------- bool whether the :class:`RDD` is empty See Also -------- :meth:`RDD.first` :meth:`pyspark.sql.DataFrame.isEmpty` Notes ----- An RDD may be empty even when it has at least 1 partition. Examples -------- >>> sc.parallelize([]).isEmpty() True >>> sc.parallelize([1]).isEmpty() False """ return self.getNumPartitions() == 0 or len(self.take(1)) == 0 [docs] def saveAsNewAPIHadoopDataset( self: "RDD[Tuple[K, V]]", conf: Dict[str, str], keyConverter: Optional[str] = None, valueConverter: Optional[str] = None, ) -> None: """ Output a Python RDD of key-value pairs (of form ``RDD[(K, V)]``) to any Hadoop file system, using the new Hadoop OutputFormat API (mapreduce package). Keys/values are converted for output using either user specified converters or, by default, "org.apache.spark.api.python.JavaToWritableConverter". .. versionadded:: 1.1.0 Parameters ---------- conf : dict Hadoop job configuration keyConverter : str, optional fully qualified classname of key converter (None by default) valueConverter : str, optional fully qualified classname of value converter (None by default) See Also -------- :meth:`SparkContext.newAPIHadoopRDD` :meth:`RDD.saveAsHadoopDataset` :meth:`RDD.saveAsHadoopFile` :meth:`RDD.saveAsNewAPIHadoopFile` :meth:`RDD.saveAsSequenceFile` Examples -------- >>> import os >>> import tempfile Set the related classes >>> output_format_class = "org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat" >>> input_format_class = "org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat" >>> key_class = "org.apache.hadoop.io.IntWritable" >>> value_class = "org.apache.hadoop.io.Text" >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "new_hadoop_file") ... ... # Create the conf for writing ... write_conf = { ... "mapreduce.job.outputformat.class": (output_format_class), ... "mapreduce.job.output.key.class": key_class, ... "mapreduce.job.output.value.class": value_class, ... "mapreduce.output.fileoutputformat.outputdir": path, ... } ... ... # Write a temporary Hadoop file ... rdd = sc.parallelize([(1, ""), (1, "a"), (3, "x")]) ... rdd.saveAsNewAPIHadoopDataset(conf=write_conf) ... ... # Create the conf for reading ... read_conf = {"mapreduce.input.fileinputformat.inputdir": path} ... ... # Load this Hadoop file as an RDD ... loaded = sc.newAPIHadoopRDD(input_format_class, ... key_class, value_class, conf=read_conf) ... sorted(loaded.collect()) [(1, ''), (1, 'a'), (3, 'x')] """ jconf = self.ctx._dictToJavaMap(conf) pickledRDD = self._pickled() assert self.ctx._jvm is not None self.ctx._jvm.PythonRDD.saveAsHadoopDataset( pickledRDD._jrdd, True, jconf, keyConverter, valueConverter, True ) [docs] def saveAsNewAPIHadoopFile( self: "RDD[Tuple[K, V]]", path: str, outputFormatClass: str, keyClass: Optional[str] = None, valueClass: Optional[str] = None, keyConverter: Optional[str] = None, valueConverter: Optional[str] = None, conf: Optional[Dict[str, str]] = None, ) -> None: """ Output a Python RDD of key-value pairs (of form ``RDD[(K, V)]``) to any Hadoop file system, using the new Hadoop OutputFormat API (mapreduce package). Key and value types will be inferred if not specified. Keys and values are converted for output using either user specified converters or "org.apache.spark.api.python.JavaToWritableConverter". The `conf` is applied on top of the base Hadoop conf associated with the SparkContext of this RDD to create a merged Hadoop MapReduce job configuration for saving the data. .. versionadded:: 1.1.0 Parameters ---------- path : str path to Hadoop file outputFormatClass : str fully qualified classname of Hadoop OutputFormat (e.g. "org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat") keyClass : str, optional fully qualified classname of key Writable class (e.g. "org.apache.hadoop.io.IntWritable", None by default) valueClass : str, optional fully qualified classname of value Writable class (e.g. "org.apache.hadoop.io.Text", None by default) keyConverter : str, optional fully qualified classname of key converter (None by default) valueConverter : str, optional fully qualified classname of value converter (None by default) conf : dict, optional Hadoop job configuration (None by default) See Also -------- :meth:`SparkContext.newAPIHadoopFile` :meth:`RDD.saveAsHadoopDataset` :meth:`RDD.saveAsNewAPIHadoopDataset` :meth:`RDD.saveAsHadoopFile` :meth:`RDD.saveAsSequenceFile` Examples -------- >>> import os >>> import tempfile Set the class of output format >>> output_format_class = "org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat" >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "hadoop_file") ... ... # Write a temporary Hadoop file ... rdd = sc.parallelize([(1, {3.0: "bb"}), (2, {1.0: "aa"}), (3, {2.0: "dd"})]) ... rdd.saveAsNewAPIHadoopFile(path, output_format_class) ... ... # Load this Hadoop file as an RDD ... sorted(sc.sequenceFile(path).collect()) [(1, {3.0: 'bb'}), (2, {1.0: 'aa'}), (3, {2.0: 'dd'})] """ jconf = self.ctx._dictToJavaMap(conf) pickledRDD = self._pickled() assert self.ctx._jvm is not None self.ctx._jvm.PythonRDD.saveAsNewAPIHadoopFile( pickledRDD._jrdd, True, path, outputFormatClass, keyClass, valueClass, keyConverter, valueConverter, jconf, ) [docs] def saveAsHadoopDataset( self: "RDD[Tuple[K, V]]", conf: Dict[str, str], keyConverter: Optional[str] = None, valueConverter: Optional[str] = None, ) -> None: """ Output a Python RDD of key-value pairs (of form ``RDD[(K, V)]``) to any Hadoop file system, using the old Hadoop OutputFormat API (mapred package). Keys/values are converted for output using either user specified converters or, by default, "org.apache.spark.api.python.JavaToWritableConverter". .. versionadded:: 1.1.0 Parameters ---------- conf : dict Hadoop job configuration keyConverter : str, optional fully qualified classname of key converter (None by default) valueConverter : str, optional fully qualified classname of value converter (None by default) See Also -------- :meth:`SparkContext.hadoopRDD` :meth:`RDD.saveAsNewAPIHadoopDataset` :meth:`RDD.saveAsHadoopFile` :meth:`RDD.saveAsNewAPIHadoopFile` :meth:`RDD.saveAsSequenceFile` Examples -------- >>> import os >>> import tempfile Set the related classes >>> output_format_class = "org.apache.hadoop.mapred.TextOutputFormat" >>> input_format_class = "org.apache.hadoop.mapred.TextInputFormat" >>> key_class = "org.apache.hadoop.io.IntWritable" >>> value_class = "org.apache.hadoop.io.Text" >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "old_hadoop_file") ... ... # Create the conf for writing ... write_conf = { ... "mapred.output.format.class": output_format_class, ... "mapreduce.job.output.key.class": key_class, ... "mapreduce.job.output.value.class": value_class, ... "mapreduce.output.fileoutputformat.outputdir": path, ... } ... ... # Write a temporary Hadoop file ... rdd = sc.parallelize([(1, ""), (1, "a"), (3, "x")]) ... rdd.saveAsHadoopDataset(conf=write_conf) ... ... # Create the conf for reading ... read_conf = {"mapreduce.input.fileinputformat.inputdir": path} ... ... # Load this Hadoop file as an RDD ... loaded = sc.hadoopRDD(input_format_class, key_class, value_class, conf=read_conf) ... sorted(loaded.collect()) [(0, '1\\t'), (0, '1\\ta'), (0, '3\\tx')] """ jconf = self.ctx._dictToJavaMap(conf) pickledRDD = self._pickled() assert self.ctx._jvm is not None self.ctx._jvm.PythonRDD.saveAsHadoopDataset( pickledRDD._jrdd, True, jconf, keyConverter, valueConverter, False ) [docs] def saveAsHadoopFile( self: "RDD[Tuple[K, V]]", path: str, outputFormatClass: str, keyClass: Optional[str] = None, valueClass: Optional[str] = None, keyConverter: Optional[str] = None, valueConverter: Optional[str] = None, conf: Optional[Dict[str, str]] = None, compressionCodecClass: Optional[str] = None, ) -> None: """ Output a Python RDD of key-value pairs (of form ``RDD[(K, V)]``) to any Hadoop file system, using the old Hadoop OutputFormat API (mapred package). Key and value types will be inferred if not specified. Keys and values are converted for output using either user specified converters or "org.apache.spark.api.python.JavaToWritableConverter". The `conf` is applied on top of the base Hadoop conf associated with the SparkContext of this RDD to create a merged Hadoop MapReduce job configuration for saving the data. .. versionadded:: 1.1.0 Parameters ---------- path : str path to Hadoop file outputFormatClass : str fully qualified classname of Hadoop OutputFormat (e.g. "org.apache.hadoop.mapred.SequenceFileOutputFormat") keyClass : str, optional fully qualified classname of key Writable class (e.g. "org.apache.hadoop.io.IntWritable", None by default) valueClass : str, optional fully qualified classname of value Writable class (e.g. "org.apache.hadoop.io.Text", None by default) keyConverter : str, optional fully qualified classname of key converter (None by default) valueConverter : str, optional fully qualified classname of value converter (None by default) conf : dict, optional (None by default) compressionCodecClass : str fully qualified classname of the compression codec class i.e. "org.apache.hadoop.io.compress.GzipCodec" (None by default) See Also -------- :meth:`SparkContext.hadoopFile` :meth:`RDD.saveAsNewAPIHadoopFile` :meth:`RDD.saveAsHadoopDataset` :meth:`RDD.saveAsNewAPIHadoopDataset` :meth:`RDD.saveAsSequenceFile` Examples -------- >>> import os >>> import tempfile Set the related classes >>> output_format_class = "org.apache.hadoop.mapred.TextOutputFormat" >>> input_format_class = "org.apache.hadoop.mapred.TextInputFormat" >>> key_class = "org.apache.hadoop.io.IntWritable" >>> value_class = "org.apache.hadoop.io.Text" >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "old_hadoop_file") ... ... # Write a temporary Hadoop file ... rdd = sc.parallelize([(1, ""), (1, "a"), (3, "x")]) ... rdd.saveAsHadoopFile(path, output_format_class, key_class, value_class) ... ... # Load this Hadoop file as an RDD ... loaded = sc.hadoopFile(path, input_format_class, key_class, value_class) ... sorted(loaded.collect()) [(0, '1\\t'), (0, '1\\ta'), (0, '3\\tx')] """ jconf = self.ctx._dictToJavaMap(conf) pickledRDD = self._pickled() assert self.ctx._jvm is not None self.ctx._jvm.PythonRDD.saveAsHadoopFile( pickledRDD._jrdd, True, path, outputFormatClass, keyClass, valueClass, keyConverter, valueConverter, jconf, compressionCodecClass, ) [docs] def saveAsSequenceFile( self: "RDD[Tuple[K, V]]", path: str, compressionCodecClass: Optional[str] = None ) -> None: """ Output a Python RDD of key-value pairs (of form ``RDD[(K, V)]``) to any Hadoop file system, using the "org.apache.hadoop.io.Writable" types that we convert from the RDD's key and value types. The mechanism is as follows: 1. Pickle is used to convert pickled Python RDD into RDD of Java objects. 2. Keys and values of this Java RDD are converted to Writables and written out. .. versionadded:: 1.1.0 Parameters ---------- path : str path to sequence file compressionCodecClass : str, optional fully qualified classname of the compression codec class i.e. "org.apache.hadoop.io.compress.GzipCodec" (None by default) See Also -------- :meth:`SparkContext.sequenceFile` :meth:`RDD.saveAsHadoopFile` :meth:`RDD.saveAsNewAPIHadoopFile` :meth:`RDD.saveAsHadoopDataset` :meth:`RDD.saveAsNewAPIHadoopDataset` :meth:`RDD.saveAsSequenceFile` Examples -------- >>> import os >>> import tempfile Set the related classes >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "sequence_file") ... ... # Write a temporary sequence file ... rdd = sc.parallelize([(1, ""), (1, "a"), (3, "x")]) ... rdd.saveAsSequenceFile(path) ... ... # Load this sequence file as an RDD ... loaded = sc.sequenceFile(path) ... sorted(loaded.collect()) [(1, ''), (1, 'a'), (3, 'x')] """ pickledRDD = self._pickled() assert self.ctx._jvm is not None self.ctx._jvm.PythonRDD.saveAsSequenceFile( pickledRDD._jrdd, True, path, compressionCodecClass ) [docs] def saveAsPickleFile(self, path: str, batchSize: int = 10) -> None: """ Save this RDD as a SequenceFile of serialized objects. The serializer used is :class:`pyspark.serializers.CPickleSerializer`, default batch size is 10. .. versionadded:: 1.1.0 Parameters ---------- path : str path to pickled file batchSize : int, optional, default 10 the number of Python objects represented as a single Java object. See Also -------- :meth:`SparkContext.pickleFile` Examples -------- >>> import os >>> import tempfile >>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "pickle_file") ... ... # Write a temporary pickled file ... sc.parallelize(range(10)).saveAsPickleFile(path, 3) ... ... # Load picked file as an RDD ... sorted(sc.pickleFile(path, 3).collect()) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] """ ser: Serializer if batchSize == 0: ser = AutoBatchedSerializer(CPickleSerializer()) else: ser = BatchedSerializer(CPickleSerializer(), batchSize) self._reserialize(ser)._jrdd.saveAsObjectFile(path) [docs] def saveAsTextFile(self, path: str, compressionCodecClass: Optional[str] = None) -> None: """ Save this RDD as a text file, using string representations of elements. .. versionadded:: 0.7.0 Parameters ---------- path : str path to text file compressionCodecClass : str, optional fully qualified classname of the compression codec class i.e. "org.apache.hadoop.io.compress.GzipCodec" (None by default) See Also -------- :meth:`SparkContext.textFile` :meth:`SparkContext.wholeTextFiles` Examples -------- >>> import os >>> import tempfile >>> from fileinput import input >>> from glob import glob >>> with tempfile.TemporaryDirectory() as d1: ... path1 = os.path.join(d1, "text_file1") ... ... # Write a temporary text file ... sc.parallelize(range(10)).saveAsTextFile(path1) ... ... # Load text file as an RDD ... ''.join(sorted(input(glob(path1 + "/part-0000*")))) '0\\n1\\n2\\n3\\n4\\n5\\n6\\n7\\n8\\n9\\n' Empty lines are tolerated when saving to text files. >>> with tempfile.TemporaryDirectory() as d2: ... path2 = os.path.join(d2, "text2_file2") ... ... # Write another temporary text file ... sc.parallelize(['', 'foo', '', 'bar', '']).saveAsTextFile(path2) ... ... # Load text file as an RDD ... ''.join(sorted(input(glob(path2 + "/part-0000*")))) '\\n\\n\\nbar\\nfoo\\n' Using compressionCodecClass >>> from fileinput import input, hook_compressed >>> with tempfile.TemporaryDirectory() as d3: ... path3 = os.path.join(d3, "text3") ... codec = "org.apache.hadoop.io.compress.GzipCodec" ... ... # Write another temporary text file with specified codec ... sc.parallelize(['foo', 'bar']).saveAsTextFile(path3, codec) ... ... # Load text file as an RDD ... result = sorted(input(glob(path3 + "/part*.gz"), openhook=hook_compressed)) ... ''.join([r.decode('utf-8') if isinstance(r, bytes) else r for r in result]) 'bar\\nfoo\\n' """ def func(split: int, iterator: Iterable[Any]) -> Iterable[bytes]: for x in iterator: if isinstance(x, bytes): yield x elif isinstance(x, str): yield x.encode("utf-8") else: yield str(x).encode("utf-8") keyed = self.mapPartitionsWithIndex(func) keyed._bypass_serializer = True # type: ignore[attr-defined] assert self.ctx._jvm is not None if compressionCodecClass: compressionCodec = self.ctx._jvm.java.lang.Class.forName(compressionCodecClass) keyed._jrdd.map(self.ctx._jvm.BytesToString()).saveAsTextFile(path, compressionCodec) else: keyed._jrdd.map(self.ctx._jvm.BytesToString()).saveAsTextFile(path) # Pair functions [docs] def collectAsMap(self: "RDD[Tuple[K, V]]") -> Dict[K, V]: """ Return the key-value pairs in this RDD to the master as a dictionary. .. versionadded:: 0.7.0 Returns ------- :class:`dict` a dictionary of (key, value) pairs See Also -------- :meth:`RDD.countByValue` Notes ----- This method should only be used if the resulting data is expected to be small, as all the data is loaded into the driver's memory. Examples -------- >>> m = sc.parallelize([(1, 2), (3, 4)]).collectAsMap() >>> m[1] 2 >>> m[3] 4 """ return dict(self.collect()) [docs] def keys(self: "RDD[Tuple[K, V]]") -> "RDD[K]": """ Return an RDD with the keys of each tuple. .. versionadded:: 0.7.0 Returns ------- :class:`RDD` a :class:`RDD` only containing the keys See Also -------- :meth:`RDD.values` Examples -------- >>> rdd = sc.parallelize([(1, 2), (3, 4)]).keys() >>> rdd.collect() [1, 3] """ return self.map(lambda x: x[0]) [docs] def values(self: "RDD[Tuple[K, V]]") -> "RDD[V]": """ Return an RDD with the values of each tuple. .. versionadded:: 0.7.0 Returns ------- :class:`RDD` a :class:`RDD` only containing the values See Also -------- :meth:`RDD.keys` Examples -------- >>> rdd = sc.parallelize([(1, 2), (3, 4)]).values() >>> rdd.collect() [2, 4] """ return self.map(lambda x: x[1]) [docs] def reduceByKey( self: "RDD[Tuple[K, V]]", func: Callable[[V, V], V], numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, V]]": """ Merge the values for each key using an associative and commutative reduce function. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce. Output will be partitioned with `numPartitions` partitions, or the default parallelism level if `numPartitions` is not specified. Default partitioner is hash-partition. .. versionadded:: 1.6.0 Parameters ---------- func : function the reduce function numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the aggregated result for each key See Also -------- :meth:`RDD.reduceByKeyLocally` :meth:`RDD.combineByKey` :meth:`RDD.aggregateByKey` :meth:`RDD.foldByKey` :meth:`RDD.groupByKey` Examples -------- >>> from operator import add >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)]) >>> sorted(rdd.reduceByKey(add).collect()) [('a', 2), ('b', 1)] """ return self.combineByKey(lambda x: x, func, func, numPartitions, partitionFunc) [docs] def reduceByKeyLocally(self: "RDD[Tuple[K, V]]", func: Callable[[V, V], V]) -> Dict[K, V]: """ Merge the values for each key using an associative and commutative reduce function, but return the results immediately to the master as a dictionary. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce. .. versionadded:: 0.7.0 Parameters ---------- func : function the reduce function Returns ------- dict a dict containing the keys and the aggregated result for each key See Also -------- :meth:`RDD.reduceByKey` :meth:`RDD.aggregateByKey` Examples -------- >>> from operator import add >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)]) >>> sorted(rdd.reduceByKeyLocally(add).items()) [('a', 2), ('b', 1)] """ func = fail_on_stopiteration(func) def reducePartition(iterator: Iterable[Tuple[K, V]]) -> Iterable[Dict[K, V]]: m: Dict[K, V] = {} for k, v in iterator: m[k] = func(m[k], v) if k in m else v yield m def mergeMaps(m1: Dict[K, V], m2: Dict[K, V]) -> Dict[K, V]: for k, v in m2.items(): m1[k] = func(m1[k], v) if k in m1 else v return m1 return self.mapPartitions(reducePartition).reduce(mergeMaps) [docs] def countByKey(self: "RDD[Tuple[K, V]]") -> Dict[K, int]: """ Count the number of elements for each key, and return the result to the master as a dictionary. .. versionadded:: 0.7.0 Returns ------- dict a dictionary of (key, count) pairs See Also -------- :meth:`RDD.collectAsMap` :meth:`RDD.countByValue` Examples -------- >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)]) >>> sorted(rdd.countByKey().items()) [('a', 2), ('b', 1)] """ return self.map(lambda x: x[0]).countByValue() [docs] def join( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, U]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, Tuple[V, U]]]": """ Return an RDD containing all pairs of elements with matching keys in `self` and `other`. Each pair of elements will be returned as a (k, (v1, v2)) tuple, where (k, v1) is in `self` and (k, v2) is in `other`. Performs a hash join across the cluster. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing all pairs of elements with matching keys See Also -------- :meth:`RDD.leftOuterJoin` :meth:`RDD.rightOuterJoin` :meth:`RDD.fullOuterJoin` :meth:`RDD.cogroup` :meth:`RDD.groupWith` :meth:`pyspark.sql.DataFrame.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd2 = sc.parallelize([("a", 2), ("a", 3)]) >>> sorted(rdd1.join(rdd2).collect()) [('a', (1, 2)), ('a', (1, 3))] """ return python_join(self, other, numPartitions) [docs] def leftOuterJoin( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, U]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, Tuple[V, Optional[U]]]]": """ Perform a left outer join of `self` and `other`. For each element (k, v) in `self`, the resulting RDD will either contain all pairs (k, (v, w)) for w in `other`, or the pair (k, (v, None)) if no elements in `other` have key k. Hash-partitions the resulting RDD into the given number of partitions. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing all pairs of elements with matching keys See Also -------- :meth:`RDD.join` :meth:`RDD.rightOuterJoin` :meth:`RDD.fullOuterJoin` :meth:`pyspark.sql.DataFrame.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd2 = sc.parallelize([("a", 2)]) >>> sorted(rdd1.leftOuterJoin(rdd2).collect()) [('a', (1, 2)), ('b', (4, None))] """ return python_left_outer_join(self, other, numPartitions) [docs] def rightOuterJoin( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, U]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, Tuple[Optional[V], U]]]": """ Perform a right outer join of `self` and `other`. For each element (k, w) in `other`, the resulting RDD will either contain all pairs (k, (v, w)) for v in this, or the pair (k, (None, w)) if no elements in `self` have key k. Hash-partitions the resulting RDD into the given number of partitions. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing all pairs of elements with matching keys See Also -------- :meth:`RDD.join` :meth:`RDD.leftOuterJoin` :meth:`RDD.fullOuterJoin` :meth:`pyspark.sql.DataFrame.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd2 = sc.parallelize([("a", 2)]) >>> sorted(rdd2.rightOuterJoin(rdd1).collect()) [('a', (2, 1)), ('b', (None, 4))] """ return python_right_outer_join(self, other, numPartitions) [docs] def fullOuterJoin( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, U]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, Tuple[Optional[V], Optional[U]]]]": """ Perform a right outer join of `self` and `other`. For each element (k, v) in `self`, the resulting RDD will either contain all pairs (k, (v, w)) for w in `other`, or the pair (k, (v, None)) if no elements in `other` have key k. Similarly, for each element (k, w) in `other`, the resulting RDD will either contain all pairs (k, (v, w)) for v in `self`, or the pair (k, (None, w)) if no elements in `self` have key k. Hash-partitions the resulting RDD into the given number of partitions. .. versionadded:: 1.2.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing all pairs of elements with matching keys See Also -------- :meth:`RDD.join` :meth:`RDD.leftOuterJoin` :meth:`RDD.fullOuterJoin` :meth:`pyspark.sql.DataFrame.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd2 = sc.parallelize([("a", 2), ("c", 8)]) >>> sorted(rdd1.fullOuterJoin(rdd2).collect()) [('a', (1, 2)), ('b', (4, None)), ('c', (None, 8))] """ return python_full_outer_join(self, other, numPartitions) # TODO: add option to control map-side combining # portable_hash is used as default, because builtin hash of None is different # cross machines. [docs] def partitionBy( self: "RDD[Tuple[K, V]]", numPartitions: Optional[int], partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, V]]": """ Return a copy of the RDD partitioned using the specified partitioner. .. versionadded:: 0.7.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` partitioned using the specified partitioner See Also -------- :meth:`RDD.repartition` :meth:`RDD.repartitionAndSortWithinPartitions` Examples -------- >>> pairs = sc.parallelize([1, 2, 3, 4, 2, 4, 1]).map(lambda x: (x, x)) >>> sets = pairs.partitionBy(2).glom().collect() >>> len(set(sets[0]).intersection(set(sets[1]))) 0 """ if numPartitions is None: numPartitions = self._defaultReducePartitions() partitioner = Partitioner(numPartitions, partitionFunc) if self.partitioner == partitioner: return self # Transferring O(n) objects to Java is too expensive. # Instead, we'll form the hash buckets in Python, # transferring O(numPartitions) objects to Java. # Each object is a (splitNumber, [objects]) pair. # In order to avoid too huge objects, the objects are # grouped into chunks. outputSerializer = self.ctx._unbatched_serializer limit = self._memory_limit() / 2 def add_shuffle_key(split: int, iterator: Iterable[Tuple[K, V]]) -> Iterable[bytes]: buckets = defaultdict(list) c, batch = 0, min(10 * numPartitions, 1000) # type: ignore[operator] for k, v in iterator: buckets[partitionFunc(k) % numPartitions].append((k, v)) # type: ignore[operator] c += 1 # check used memory and avg size of chunk of objects if c % 1000 == 0 and get_used_memory() > limit or c > batch: n, size = len(buckets), 0 for split in list(buckets.keys()): yield pack_long(split) d = outputSerializer.dumps(buckets[split]) del buckets[split] yield d size += len(d) avg = int(size / n) >> 20 # let 1M < avg < 10M if avg < 1: batch = min(sys.maxsize, batch * 1.5) # type: ignore[assignment] elif avg > 10: batch = max(int(batch / 1.5), 1) c = 0 for split, items in buckets.items(): yield pack_long(split) yield outputSerializer.dumps(items) keyed = self.mapPartitionsWithIndex(add_shuffle_key, preservesPartitioning=True) keyed._bypass_serializer = True # type: ignore[attr-defined] assert self.ctx._jvm is not None with SCCallSiteSync(self.context): pairRDD = self.ctx._jvm.PairwiseRDD(keyed._jrdd.rdd()).asJavaPairRDD() jpartitioner = self.ctx._jvm.PythonPartitioner(numPartitions, id(partitionFunc)) jrdd = self.ctx._jvm.PythonRDD.valueOfPair(pairRDD.partitionBy(jpartitioner)) rdd: "RDD[Tuple[K, V]]" = RDD(jrdd, self.ctx, BatchedSerializer(outputSerializer)) rdd.partitioner = partitioner return rdd # TODO: add control over map-side aggregation [docs] def combineByKey( self: "RDD[Tuple[K, V]]", createCombiner: Callable[[V], U], mergeValue: Callable[[U, V], U], mergeCombiners: Callable[[U, U], U], numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, U]]": """ Generic function to combine the elements for each key using a custom set of aggregation functions. Turns an RDD[(K, V)] into a result of type RDD[(K, C)], for a "combined type" C. To avoid memory allocation, both mergeValue and mergeCombiners are allowed to modify and return their first argument instead of creating a new C. In addition, users can control the partitioning of the output RDD. .. versionadded:: 0.7.0 Parameters ---------- createCombiner : function a function to turns a V into a C mergeValue : function a function to merge a V into a C mergeCombiners : function a function to combine two C's into a single one numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the aggregated result for each key See Also -------- :meth:`RDD.reduceByKey` :meth:`RDD.aggregateByKey` :meth:`RDD.foldByKey` :meth:`RDD.groupByKey` Notes ----- V and C can be different -- for example, one might group an RDD of type (Int, Int) into an RDD of type (Int, List[Int]). Examples -------- >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 2)]) >>> def to_list(a): ... return [a] ... >>> def append(a, b): ... a.append(b) ... return a ... >>> def extend(a, b): ... a.extend(b) ... return a ... >>> sorted(rdd.combineByKey(to_list, append, extend).collect()) [('a', [1, 2]), ('b', [1])] """ if numPartitions is None: numPartitions = self._defaultReducePartitions() serializer = self.ctx.serializer memory = self._memory_limit() agg = Aggregator(createCombiner, mergeValue, mergeCombiners) def combineLocally(iterator: Iterable[Tuple[K, V]]) -> Iterable[Tuple[K, U]]: merger = ExternalMerger(agg, memory * 0.9, serializer) merger.mergeValues(iterator) return merger.items() locally_combined = self.mapPartitions(combineLocally, preservesPartitioning=True) shuffled = locally_combined.partitionBy(numPartitions, partitionFunc) def _mergeCombiners(iterator: Iterable[Tuple[K, U]]) -> Iterable[Tuple[K, U]]: merger = ExternalMerger(agg, memory, serializer) merger.mergeCombiners(iterator) return merger.items() return shuffled.mapPartitions(_mergeCombiners, preservesPartitioning=True) [docs] def aggregateByKey( self: "RDD[Tuple[K, V]]", zeroValue: U, seqFunc: Callable[[U, V], U], combFunc: Callable[[U, U], U], numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, U]]": """ Aggregate the values of each key, using given combine functions and a neutral "zero value". This function can return a different result type, U, than the type of the values in this RDD, V. Thus, we need one operation for merging a V into a U and one operation for merging two U's, The former operation is used for merging values within a partition, and the latter is used for merging values between partitions. To avoid memory allocation, both of these functions are allowed to modify and return their first argument instead of creating a new U. .. versionadded:: 1.1.0 Parameters ---------- zeroValue : U the initial value for the accumulated result of each partition seqFunc : function a function to merge a V into a U combFunc : function a function to combine two U's into a single one numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the aggregated result for each key See Also -------- :meth:`RDD.reduceByKey` :meth:`RDD.combineByKey` :meth:`RDD.foldByKey` :meth:`RDD.groupByKey` Examples -------- >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 2)]) >>> seqFunc = (lambda x, y: (x[0] + y, x[1] + 1)) >>> combFunc = (lambda x, y: (x[0] + y[0], x[1] + y[1])) >>> sorted(rdd.aggregateByKey((0, 0), seqFunc, combFunc).collect()) [('a', (3, 2)), ('b', (1, 1))] """ def createZero() -> U: return copy.deepcopy(zeroValue) return self.combineByKey( lambda v: seqFunc(createZero(), v), seqFunc, combFunc, numPartitions, partitionFunc ) [docs] def foldByKey( self: "RDD[Tuple[K, V]]", zeroValue: V, func: Callable[[V, V], V], numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, V]]": """ Merge the values for each key using an associative function "func" and a neutral "zeroValue" which may be added to the result an arbitrary number of times, and must not change the result (e.g., 0 for addition, or 1 for multiplication.). .. versionadded:: 1.1.0 Parameters ---------- zeroValue : V the initial value for the accumulated result of each partition func : function a function to combine two V's into a single one numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the aggregated result for each key See Also -------- :meth:`RDD.reduceByKey` :meth:`RDD.combineByKey` :meth:`RDD.aggregateByKey` :meth:`RDD.groupByKey` Examples -------- >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)]) >>> from operator import add >>> sorted(rdd.foldByKey(0, add).collect()) [('a', 2), ('b', 1)] """ def createZero() -> V: return copy.deepcopy(zeroValue) return self.combineByKey( lambda v: func(createZero(), v), func, func, numPartitions, partitionFunc ) def _memory_limit(self) -> int: return _parse_memory(self.ctx._conf.get("spark.python.worker.memory", "512m")) # TODO: support variant with custom partitioner [docs] def groupByKey( self: "RDD[Tuple[K, V]]", numPartitions: Optional[int] = None, partitionFunc: Callable[[K], int] = portable_hash, ) -> "RDD[Tuple[K, Iterable[V]]]": """ Group the values for each key in the RDD into a single sequence. Hash-partitions the resulting RDD with numPartitions partitions. .. versionadded:: 0.7.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` partitionFunc : function, optional, default `portable_hash` function to compute the partition index Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the grouped result for each key See Also -------- :meth:`RDD.reduceByKey` :meth:`RDD.combineByKey` :meth:`RDD.aggregateByKey` :meth:`RDD.foldByKey` Notes ----- If you are grouping in order to perform an aggregation (such as a sum or average) over each key, using reduceByKey or aggregateByKey will provide much better performance. Examples -------- >>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)]) >>> sorted(rdd.groupByKey().mapValues(len).collect()) [('a', 2), ('b', 1)] >>> sorted(rdd.groupByKey().mapValues(list).collect()) [('a', [1, 1]), ('b', [1])] """ def createCombiner(x: V) -> List[V]: return [x] def mergeValue(xs: List[V], x: V) -> List[V]: xs.append(x) return xs def mergeCombiners(a: List[V], b: List[V]) -> List[V]: a.extend(b) return a memory = self._memory_limit() serializer = self._jrdd_deserializer agg = Aggregator(createCombiner, mergeValue, mergeCombiners) def combine(iterator: Iterable[Tuple[K, V]]) -> Iterable[Tuple[K, List[V]]]: merger = ExternalMerger(agg, memory * 0.9, serializer) merger.mergeValues(iterator) return merger.items() locally_combined = self.mapPartitions(combine, preservesPartitioning=True) shuffled = locally_combined.partitionBy(numPartitions, partitionFunc) def groupByKey(it: Iterable[Tuple[K, List[V]]]) -> Iterable[Tuple[K, List[V]]]: merger = ExternalGroupBy(agg, memory, serializer) merger.mergeCombiners(it) return merger.items() return shuffled.mapPartitions(groupByKey, True).mapValues(ResultIterable) [docs] def flatMapValues( self: "RDD[Tuple[K, V]]", f: Callable[[V], Iterable[U]] ) -> "RDD[Tuple[K, U]]": """ Pass each value in the key-value pair RDD through a flatMap function without changing the keys; this also retains the original RDD's partitioning. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to turn a V into a sequence of U Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the flat-mapped value See Also -------- :meth:`RDD.flatMap` :meth:`RDD.mapValues` Examples -------- >>> rdd = sc.parallelize([("a", ["x", "y", "z"]), ("b", ["p", "r"])]) >>> def f(x): return x >>> rdd.flatMapValues(f).collect() [('a', 'x'), ('a', 'y'), ('a', 'z'), ('b', 'p'), ('b', 'r')] """ def flat_map_fn(kv: Tuple[K, V]) -> Iterable[Tuple[K, U]]: return ((kv[0], x) for x in f(kv[1])) return self.flatMap(flat_map_fn, preservesPartitioning=True) [docs] def mapValues(self: "RDD[Tuple[K, V]]", f: Callable[[V], U]) -> "RDD[Tuple[K, U]]": """ Pass each value in the key-value pair RDD through a map function without changing the keys; this also retains the original RDD's partitioning. .. versionadded:: 0.7.0 Parameters ---------- f : function a function to turn a V into a U Returns ------- :class:`RDD` a :class:`RDD` containing the keys and the mapped value See Also -------- :meth:`RDD.map` :meth:`RDD.flatMapValues` Examples -------- >>> rdd = sc.parallelize([("a", ["apple", "banana", "lemon"]), ("b", ["grapes"])]) >>> def f(x): return len(x) >>> rdd.mapValues(f).collect() [('a', 3), ('b', 1)] """ def map_values_fn(kv: Tuple[K, V]) -> Tuple[K, U]: return kv[0], f(kv[1]) return self.map(map_values_fn, preservesPartitioning=True) @overload def groupWith( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, V1]]" ) -> "RDD[Tuple[K, Tuple[ResultIterable[V], ResultIterable[V1]]]]": ... @overload def groupWith( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, V1]]", __o1: "RDD[Tuple[K, V2]]" ) -> "RDD[Tuple[K, Tuple[ResultIterable[V], ResultIterable[V1], ResultIterable[V2]]]]": ... @overload def groupWith( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, V1]]", _o1: "RDD[Tuple[K, V2]]", _o2: "RDD[Tuple[K, V3]]", ) -> """RDD[ Tuple[ K, Tuple[ ResultIterable[V], ResultIterable[V1], ResultIterable[V2], ResultIterable[V3], ], ] ]""": ... [docs] def groupWith( # type: ignore[misc] self: "RDD[Tuple[Any, Any]]", other: "RDD[Tuple[Any, Any]]", *others: "RDD[Tuple[Any, Any]]" ) -> "RDD[Tuple[Any, Tuple[ResultIterable[Any], ...]]]": """ Alias for cogroup but with support for multiple RDDs. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` others : :class:`RDD` other :class:`RDD`\\s Returns ------- :class:`RDD` a :class:`RDD` containing the keys and cogrouped values See Also -------- :meth:`RDD.cogroup` :meth:`RDD.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 5), ("b", 6)]) >>> rdd2 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd3 = sc.parallelize([("a", 2)]) >>> rdd4 = sc.parallelize([("b", 42)]) >>> [(x, tuple(map(list, y))) for x, y in ... sorted(list(rdd1.groupWith(rdd2, rdd3, rdd4).collect()))] [('a', ([5], [1], [2], [])), ('b', ([6], [4], [], [42]))] """ return python_cogroup((self, other) + others, numPartitions=None) # TODO: add variant with custom partitioner [docs] def cogroup( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, U]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, Tuple[ResultIterable[V], ResultIterable[U]]]]": """ For each key k in `self` or `other`, return a resulting RDD that contains a tuple with the list of values for that key in `self` as well as `other`. .. versionadded:: 0.7.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing the keys and cogrouped values See Also -------- :meth:`RDD.groupWith` :meth:`RDD.join` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4)]) >>> rdd2 = sc.parallelize([("a", 2)]) >>> [(x, tuple(map(list, y))) for x, y in sorted(list(rdd1.cogroup(rdd2).collect()))] [('a', ([1], [2])), ('b', ([4], []))] """ return python_cogroup((self, other), numPartitions) [docs] def sampleByKey( self: "RDD[Tuple[K, V]]", withReplacement: bool, fractions: Dict[K, Union[float, int]], seed: Optional[int] = None, ) -> "RDD[Tuple[K, V]]": """ Return a subset of this RDD sampled by key (via stratified sampling). Create a sample of this RDD using variable sampling rates for different keys as specified by fractions, a key to sampling rate map. .. versionadded:: 0.7.0 Parameters ---------- withReplacement : bool whether to sample with or without replacement fractions : dict map of specific keys to sampling rates seed : int, optional seed for the random number generator Returns ------- :class:`RDD` a :class:`RDD` containing the stratified sampling result See Also -------- :meth:`RDD.sample` Examples -------- >>> fractions = {"a": 0.2, "b": 0.1} >>> rdd = sc.parallelize(fractions.keys()).cartesian(sc.parallelize(range(0, 1000))) >>> sample = dict(rdd.sampleByKey(False, fractions, 2).groupByKey().collect()) >>> 100 < len(sample["a"]) < 300 and 50 < len(sample["b"]) < 150 True >>> max(sample["a"]) <= 999 and min(sample["a"]) >= 0 True >>> max(sample["b"]) <= 999 and min(sample["b"]) >= 0 True """ for fraction in fractions.values(): assert fraction >= 0.0, "Negative fraction value: %s" % fraction return self.mapPartitionsWithIndex( RDDStratifiedSampler(withReplacement, fractions, seed).func, True ) [docs] def subtractByKey( self: "RDD[Tuple[K, V]]", other: "RDD[Tuple[K, Any]]", numPartitions: Optional[int] = None, ) -> "RDD[Tuple[K, V]]": """ Return each (key, value) pair in `self` that has no pair with matching key in `other`. .. versionadded:: 0.9.1 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` with the pairs from this whose keys are not in `other` See Also -------- :meth:`RDD.subtract` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4), ("b", 5), ("a", 2)]) >>> rdd2 = sc.parallelize([("a", 3), ("c", None)]) >>> sorted(rdd1.subtractByKey(rdd2).collect()) [('b', 4), ('b', 5)] """ def filter_func(pair: Tuple[K, Tuple[V, Any]]) -> bool: key, (val1, val2) = pair return val1 and not val2 # type: ignore[return-value] return ( self.cogroup(other, numPartitions) .filter(filter_func) # type: ignore[arg-type] .flatMapValues(lambda x: x[0]) ) [docs] def subtract(self: "RDD[T]", other: "RDD[T]", numPartitions: Optional[int] = None) -> "RDD[T]": """ Return each value in `self` that is not contained in `other`. .. versionadded:: 0.9.1 Parameters ---------- other : :class:`RDD` another :class:`RDD` numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` with the elements from this that are not in `other` See Also -------- :meth:`RDD.subtractByKey` Examples -------- >>> rdd1 = sc.parallelize([("a", 1), ("b", 4), ("b", 5), ("a", 3)]) >>> rdd2 = sc.parallelize([("a", 3), ("c", None)]) >>> sorted(rdd1.subtract(rdd2).collect()) [('a', 1), ('b', 4), ('b', 5)] """ # note: here 'True' is just a placeholder rdd = other.map(lambda x: (x, True)) return self.map(lambda x: (x, True)).subtractByKey(rdd, numPartitions).keys() [docs] def keyBy(self: "RDD[T]", f: Callable[[T], K]) -> "RDD[Tuple[K, T]]": """ Creates tuples of the elements in this RDD by applying `f`. .. versionadded:: 0.9.1 Parameters ---------- f : function a function to compute the key Returns ------- :class:`RDD` a :class:`RDD` with the elements from this that are not in `other` See Also -------- :meth:`RDD.map` :meth:`RDD.keys` :meth:`RDD.values` Examples -------- >>> rdd1 = sc.parallelize(range(0,3)).keyBy(lambda x: x*x) >>> rdd2 = sc.parallelize(zip(range(0,5), range(0,5))) >>> [(x, list(map(list, y))) for x, y in sorted(rdd1.cogroup(rdd2).collect())] [(0, [[0], [0]]), (1, [[1], [1]]), (2, [[], [2]]), (3, [[], [3]]), (4, [[2], [4]])] """ return self.map(lambda x: (f(x), x)) [docs] def repartition(self: "RDD[T]", numPartitions: int) -> "RDD[T]": """ Return a new RDD that has exactly numPartitions partitions. Can increase or decrease the level of parallelism in this RDD. Internally, this uses a shuffle to redistribute data. If you are decreasing the number of partitions in this RDD, consider using `coalesce`, which can avoid performing a shuffle. .. versionadded:: 1.0.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` with exactly numPartitions partitions See Also -------- :meth:`RDD.coalesce` :meth:`RDD.partitionBy` :meth:`RDD.repartitionAndSortWithinPartitions` Examples -------- >>> rdd = sc.parallelize([1,2,3,4,5,6,7], 4) >>> sorted(rdd.glom().collect()) [[1], [2, 3], [4, 5], [6, 7]] >>> len(rdd.repartition(2).glom().collect()) 2 >>> len(rdd.repartition(10).glom().collect()) 10 """ return self.coalesce(numPartitions, shuffle=True) [docs] def coalesce(self: "RDD[T]", numPartitions: int, shuffle: bool = False) -> "RDD[T]": """ Return a new RDD that is reduced into `numPartitions` partitions. .. versionadded:: 1.0.0 Parameters ---------- numPartitions : int, optional the number of partitions in new :class:`RDD` shuffle : bool, optional, default False whether to add a shuffle step Returns ------- :class:`RDD` a :class:`RDD` that is reduced into `numPartitions` partitions See Also -------- :meth:`RDD.repartition` Examples -------- >>> sc.parallelize([1, 2, 3, 4, 5], 3).glom().collect() [[1], [2, 3], [4, 5]] >>> sc.parallelize([1, 2, 3, 4, 5], 3).coalesce(1).glom().collect() [[1, 2, 3, 4, 5]] """ if not numPartitions > 0: raise ValueError("Number of partitions must be positive.") if shuffle: # Decrease the batch size in order to distribute evenly the elements across output # partitions. Otherwise, repartition will possibly produce highly skewed partitions. batchSize = min(10, self.ctx._batchSize or 1024) ser = BatchedSerializer(CPickleSerializer(), batchSize) selfCopy = self._reserialize(ser) jrdd_deserializer = selfCopy._jrdd_deserializer jrdd = selfCopy._jrdd.coalesce(numPartitions, shuffle) else: jrdd_deserializer = self._jrdd_deserializer jrdd = self._jrdd.coalesce(numPartitions, shuffle) return RDD(jrdd, self.ctx, jrdd_deserializer) [docs] def zip(self: "RDD[T]", other: "RDD[U]") -> "RDD[Tuple[T, U]]": """ Zips this RDD with another one, returning key-value pairs with the first element in each RDD second element in each RDD, etc. Assumes that the two RDDs have the same number of partitions and the same number of elements in each partition (e.g. one was made through a map on the other). .. versionadded:: 1.0.0 Parameters ---------- other : :class:`RDD` another :class:`RDD` Returns ------- :class:`RDD` a :class:`RDD` containing the zipped key-value pairs See Also -------- :meth:`RDD.zipWithIndex` :meth:`RDD.zipWithUniqueId` Examples -------- >>> rdd1 = sc.parallelize(range(0,5)) >>> rdd2 = sc.parallelize(range(1000, 1005)) >>> rdd1.zip(rdd2).collect() [(0, 1000), (1, 1001), (2, 1002), (3, 1003), (4, 1004)] """ def get_batch_size(ser: Serializer) -> int: if isinstance(ser, BatchedSerializer): return ser.batchSize return 1 # not batched def batch_as(rdd: "RDD[V]", batchSize: int) -> "RDD[V]": return rdd._reserialize(BatchedSerializer(CPickleSerializer(), batchSize)) my_batch = get_batch_size(self._jrdd_deserializer) other_batch = get_batch_size(other._jrdd_deserializer) if my_batch != other_batch or not my_batch: # use the smallest batchSize for both of them batchSize = min(my_batch, other_batch) if batchSize <= 0: # auto batched or unlimited batchSize = 100 other = batch_as(other, batchSize) self = batch_as(self, batchSize) if self.getNumPartitions() != other.getNumPartitions(): raise ValueError("Can only zip with RDD which has the same number of partitions") # There will be an Exception in JVM if there are different number # of items in each partitions. pairRDD = self._jrdd.zip(other._jrdd) deserializer = PairDeserializer(self._jrdd_deserializer, other._jrdd_deserializer) return RDD(pairRDD, self.ctx, deserializer) [docs] def zipWithIndex(self: "RDD[T]") -> "RDD[Tuple[T, int]]": """ Zips this RDD with its element indices. The ordering is first based on the partition index and then the ordering of items within each partition. So the first item in the first partition gets index 0, and the last item in the last partition receives the largest index. This method needs to trigger a spark job when this RDD contains more than one partitions. .. versionadded:: 1.2.0 Returns ------- :class:`RDD` a :class:`RDD` containing the zipped key-index pairs See Also -------- :meth:`RDD.zip` :meth:`RDD.zipWithUniqueId` Examples -------- >>> sc.parallelize(["a", "b", "c", "d"], 3).zipWithIndex().collect() [('a', 0), ('b', 1), ('c', 2), ('d', 3)] """ starts = [0] if self.getNumPartitions() > 1: nums = self.mapPartitions(lambda it: [sum(1 for i in it)]).collect() for i in range(len(nums) - 1): starts.append(starts[-1] + nums[i]) def func(k: int, it: Iterable[T]) -> Iterable[Tuple[T, int]]: for i, v in enumerate(it, starts[k]): yield v, i return self.mapPartitionsWithIndex(func) [docs] def zipWithUniqueId(self: "RDD[T]") -> "RDD[Tuple[T, int]]": """ Zips this RDD with generated unique Long ids. Items in the kth partition will get ids k, n+k, 2*n+k, ..., where n is the number of partitions. So there may exist gaps, but this method won't trigger a spark job, which is different from :meth:`zipWithIndex`. .. versionadded:: 1.2.0 Returns ------- :class:`RDD` a :class:`RDD` containing the zipped key-UniqueId pairs See Also -------- :meth:`RDD.zip` :meth:`RDD.zipWithIndex` Examples -------- >>> sc.parallelize(["a", "b", "c", "d", "e"], 3).zipWithUniqueId().collect() [('a', 0), ('b', 1), ('c', 4), ('d', 2), ('e', 5)] """ n = self.getNumPartitions() def func(k: int, it: Iterable[T]) -> Iterable[Tuple[T, int]]: for i, v in enumerate(it): yield v, i * n + k return self.mapPartitionsWithIndex(func) [docs] def name(self) -> Optional[str]: """ Return the name of this RDD. .. versionadded:: 1.0.0 Returns ------- str :class:`RDD` name See Also -------- :meth:`RDD.setName` Examples -------- >>> rdd = sc.range(5) >>> rdd.name() == None True """ n = self._jrdd.name() return n if n else None [docs] def setName(self: "RDD[T]", name: str) -> "RDD[T]": """ Assign a name to this RDD. .. versionadded:: 1.0.0 Parameters ---------- name : str new name Returns ------- :class:`RDD` the same :class:`RDD` with name updated See Also -------- :meth:`RDD.name` Examples -------- >>> rdd = sc.parallelize([1, 2]) >>> rdd.setName('I am an RDD').name() 'I am an RDD' """ self._jrdd.setName(name) return self [docs] def toDebugString(self) -> Optional[bytes]: """ A description of this RDD and its recursive dependencies for debugging. .. versionadded:: 1.0.0 Returns ------- bytes debugging information of this :class:`RDD` Examples -------- >>> rdd = sc.range(5) >>> rdd.toDebugString() b'...PythonRDD...ParallelCollectionRDD...' """ debug_string = self._jrdd.toDebugString() return debug_string.encode("utf-8") if debug_string else None [docs] def getStorageLevel(self) -> StorageLevel: """ Get the RDD's current storage level. .. versionadded:: 1.0.0 Returns ------- :class:`StorageLevel` current :class:`StorageLevel` See Also -------- :meth:`RDD.name` Examples -------- >>> rdd = sc.parallelize([1,2]) >>> rdd.getStorageLevel() StorageLevel(False, False, False, False, 1) >>> print(rdd.getStorageLevel()) Serialized 1x Replicated """ java_storage_level = self._jrdd.getStorageLevel() storage_level = StorageLevel( java_storage_level.useDisk(), java_storage_level.useMemory(), java_storage_level.useOffHeap(), java_storage_level.deserialized(), java_storage_level.replication(), ) return storage_level def _defaultReducePartitions(self) -> int: """ Returns the default number of partitions to use during reduce tasks (e.g., groupBy). If spark.default.parallelism is set, then we'll use the value from SparkContext defaultParallelism, otherwise we'll use the number of partitions in this RDD. This mirrors the behavior of the Scala Partitioner#defaultPartitioner, intended to reduce the likelihood of OOMs. Once PySpark adopts Partitioner-based APIs, this behavior will be inherent. """ if self.ctx._conf.contains("spark.default.parallelism"): return self.ctx.defaultParallelism else: return self.getNumPartitions() [docs] def lookup(self: "RDD[Tuple[K, V]]", key: K) -> List[V]: """ Return the list of values in the RDD for key `key`. This operation is done efficiently if the RDD has a known partitioner by only searching the partition that the key maps to. .. versionadded:: 1.2.0 Parameters ---------- key : K the key to look up Returns ------- list the list of values in the :class:`RDD` for key `key` Examples -------- >>> l = range(1000) >>> rdd = sc.parallelize(zip(l, l), 10) >>> rdd.lookup(42) # slow [42] >>> sorted = rdd.sortByKey() >>> sorted.lookup(42) # fast [42] >>> sorted.lookup(1024) [] >>> rdd2 = sc.parallelize([(('a', 'b'), 'c')]).groupByKey() >>> list(rdd2.lookup(('a', 'b'))[0]) ['c'] """ values = self.filter(lambda kv: kv[0] == key).values() if self.partitioner is not None: return self.ctx.runJob(values, lambda x: x, [self.partitioner(key)]) return values.collect() def _to_java_object_rdd(self) -> "JavaObject": """Return a JavaRDD of Object by unpickling It will convert each Python object into Java object by Pickle, whenever the RDD is serialized in batch or not. """ rdd = self._pickled() assert self.ctx._jvm is not None return self.ctx._jvm.SerDeUtil.pythonToJava(rdd._jrdd, True) [docs] def countApprox(self, timeout: int, confidence: float = 0.95) -> int: """ Approximate version of count() that returns a potentially incomplete result within a timeout, even if not all tasks have finished. .. versionadded:: 1.2.0 Parameters ---------- timeout : int maximum time to wait for the job, in milliseconds confidence : float the desired statistical confidence in the result Returns ------- int a potentially incomplete result, with error bounds See Also -------- :meth:`RDD.count` Examples -------- >>> rdd = sc.parallelize(range(1000), 10) >>> rdd.countApprox(1000, 1.0) 1000 """ drdd = self.mapPartitions(lambda it: [float(sum(1 for i in it))]) return int(drdd.sumApprox(timeout, confidence)) [docs] def sumApprox( self: "RDD[Union[float, int]]", timeout: int, confidence: float = 0.95 ) -> BoundedFloat: """ Approximate operation to return the sum within a timeout or meet the confidence. .. versionadded:: 1.2.0 Parameters ---------- timeout : int maximum time to wait for the job, in milliseconds confidence : float the desired statistical confidence in the result Returns ------- :class:`BoundedFloat` a potentially incomplete result, with error bounds See Also -------- :meth:`RDD.sum` Examples -------- >>> rdd = sc.parallelize(range(1000), 10) >>> r = sum(range(1000)) >>> abs(rdd.sumApprox(1000) - r) / r < 0.05 True """ jrdd = self.mapPartitions(lambda it: [float(sum(it))])._to_java_object_rdd() assert self.ctx._jvm is not None jdrdd = self.ctx._jvm.JavaDoubleRDD.fromRDD(jrdd.rdd()) r = jdrdd.sumApprox(timeout, confidence).getFinalValue() return BoundedFloat(r.mean(), r.confidence(), r.low(), r.high()) [docs] def meanApprox( self: "RDD[Union[float, int]]", timeout: int, confidence: float = 0.95 ) -> BoundedFloat: """ Approximate operation to return the mean within a timeout or meet the confidence. .. versionadded:: 1.2.0 Parameters ---------- timeout : int maximum time to wait for the job, in milliseconds confidence : float the desired statistical confidence in the result Returns ------- :class:`BoundedFloat` a potentially incomplete result, with error bounds See Also -------- :meth:`RDD.mean` Examples -------- >>> rdd = sc.parallelize(range(1000), 10) >>> r = sum(range(1000)) / 1000.0 >>> abs(rdd.meanApprox(1000) - r) / r < 0.05 True """ jrdd = self.map(float)._to_java_object_rdd() assert self.ctx._jvm is not None jdrdd = self.ctx._jvm.JavaDoubleRDD.fromRDD(jrdd.rdd()) r = jdrdd.meanApprox(timeout, confidence).getFinalValue() return BoundedFloat(r.mean(), r.confidence(), r.low(), r.high()) [docs] def countApproxDistinct(self: "RDD[T]", relativeSD: float = 0.05) -> int: """ Return approximate number of distinct elements in the RDD. .. versionadded:: 1.2.0 Parameters ---------- relativeSD : float, optional Relative accuracy. Smaller values create counters that require more space. It must be greater than 0.000017. Returns ------- int approximate number of distinct elements See Also -------- :meth:`RDD.distinct` Notes ----- The algorithm used is based on streamlib's implementation of `"HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm", available here <https://doi.org/10.1145/2452376.2452456>`_. Examples -------- >>> n = sc.parallelize(range(1000)).map(str).countApproxDistinct() >>> 900 < n < 1100 True >>> n = sc.parallelize([i % 20 for i in range(1000)]).countApproxDistinct() >>> 16 < n < 24 True """ if relativeSD < 0.000017: raise ValueError("relativeSD should be greater than 0.000017") # the hash space in Java is 2^32 hashRDD = self.map(lambda x: portable_hash(x) & 0xFFFFFFFF) return hashRDD._to_java_object_rdd().countApproxDistinct(relativeSD) [docs] def toLocalIterator(self: "RDD[T]", prefetchPartitions: bool = False) -> Iterator[T]: """ Return an iterator that contains all of the elements in this RDD. The iterator will consume as much memory as the largest partition in this RDD. With prefetch it may consume up to the memory of the 2 largest partitions. .. versionadded:: 1.3.0 Parameters ---------- prefetchPartitions : bool, optional If Spark should pre-fetch the next partition before it is needed. Returns ------- :class:`collections.abc.Iterator` an iterator that contains all of the elements in this :class:`RDD` See Also -------- :meth:`RDD.collect` :meth:`pyspark.sql.DataFrame.toLocalIterator` Examples -------- >>> rdd = sc.parallelize(range(10)) >>> [x for x in rdd.toLocalIterator()] [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] """ assert self.ctx._jvm is not None with SCCallSiteSync(self.context): sock_info = self.ctx._jvm.PythonRDD.toLocalIteratorAndServe( self._jrdd.rdd(), prefetchPartitions ) return _local_iterator_from_socket(sock_info, self._jrdd_deserializer) [docs] def barrier(self: "RDD[T]") -> "RDDBarrier[T]": """ Marks the current stage as a barrier stage, where Spark must launch all tasks together. In case of a task failure, instead of only restarting the failed task, Spark will abort the entire stage and relaunch all tasks for this stage. The barrier execution mode feature is experimental and it only handles limited scenarios. Please read the linked SPIP and design docs to understand the limitations and future plans. .. versionadded:: 2.4.0 Returns ------- :class:`RDDBarrier` instance that provides actions within a barrier stage. See Also -------- :class:`pyspark.BarrierTaskContext` Notes ----- For additional information see - `SPIP: Barrier Execution Mode <http://jira.apache.org/jira/browse/SPARK-24374>`_ - `Design Doc <https://jira.apache.org/jira/browse/SPARK-24582>`_ This API is experimental """ return RDDBarrier(self) def _is_barrier(self) -> bool: """ Whether this RDD is in a barrier stage. """ return self._jrdd.rdd().isBarrier() [docs] def withResources(self: "RDD[T]", profile: ResourceProfile) -> "RDD[T]": """ Specify a :class:`pyspark.resource.ResourceProfile` to use when calculating this RDD. This is only supported on certain cluster managers and currently requires dynamic allocation to be enabled. It will result in new executors with the resources specified being acquired to calculate the RDD. .. versionadded:: 3.1.0 Parameters ---------- profile : :class:`pyspark.resource.ResourceProfile` a resource profile Returns ------- :class:`RDD` the same :class:`RDD` with user specified profile See Also -------- :meth:`RDD.getResourceProfile` Notes ----- This API is experimental """ self.has_resource_profile = True if profile._java_resource_profile is not None: jrp = profile._java_resource_profile else: assert self.ctx._jvm is not None builder = self.ctx._jvm.org.apache.spark.resource.ResourceProfileBuilder() ereqs = ExecutorResourceRequests(self.ctx._jvm, profile._executor_resource_requests) treqs = TaskResourceRequests(self.ctx._jvm, profile._task_resource_requests) builder.require(ereqs._java_executor_resource_requests) builder.require(treqs._java_task_resource_requests) jrp = builder.build() self._jrdd.withResources(jrp) return self [docs] def getResourceProfile(self) -> Optional[ResourceProfile]: """ Get the :class:`pyspark.resource.ResourceProfile` specified with this RDD or None if it wasn't specified. .. versionadded:: 3.1.0 Returns ------- class:`pyspark.resource.ResourceProfile` The user specified profile or None if none were specified See Also -------- :meth:`RDD.withResources` Notes ----- This API is experimental """ rp = self._jrdd.getResourceProfile() if rp is not None: return ResourceProfile(_java_resource_profile=rp) else: return None @overload def toDF( self: "RDD[RowLike]", schema: Optional[Union[List[str], Tuple[str, ...]]] = None, sampleRatio: Optional[float] = None, ) -> "DataFrame": ... @overload def toDF( self: "RDD[RowLike]", schema: Optional[Union["StructType", str]] = None ) -> "DataFrame": ... @overload def toDF( self: "RDD[AtomicValue]", schema: Union["AtomicType", str], ) -> "DataFrame": ... def toDF( self: "RDD[Any]", schema: Optional[Any] = None, sampleRatio: Optional[float] = None ) -> "DataFrame": raise RuntimeError("""RDD.toDF was called before SparkSession was initialized.""") def _prepare_for_python_RDD(sc: "SparkContext", command: Any) -> Tuple[bytes, Any, Any, Any]: # the serialized command will be compressed by broadcast ser = CloudPickleSerializer() pickled_command = ser.dumps(command) assert sc._jvm is not None if len(pickled_command) > sc._jvm.PythonUtils.getBroadcastThreshold(sc._jsc): # Default 1M # The broadcast will have same life cycle as created PythonRDD broadcast = sc.broadcast(pickled_command) pickled_command = ser.dumps(broadcast) broadcast_vars = [x._jbroadcast for x in sc._pickled_broadcast_vars] sc._pickled_broadcast_vars.clear() return pickled_command, broadcast_vars, sc.environment, sc._python_includes def _wrap_function( sc: "SparkContext", func: Callable, deserializer: Any, serializer: Any, profiler: Any = None ) -> "JavaObject": assert deserializer, "deserializer should not be empty" assert serializer, "serializer should not be empty" command = (func, profiler, deserializer, serializer) pickled_command, broadcast_vars, env, includes = _prepare_for_python_RDD(sc, command) assert sc._jvm is not None return sc._jvm.SimplePythonFunction( bytearray(pickled_command), env, includes, sc.pythonExec, sc.pythonVer, broadcast_vars, sc._javaAccumulator, ) [docs]class RDDBarrier(Generic[T]): """ Wraps an RDD in a barrier stage, which forces Spark to launch tasks of this stage together. :class:`RDDBarrier` instances are created by :meth:`RDD.barrier`. .. versionadded:: 2.4.0 Notes ----- This API is experimental """ def __init__(self, rdd: RDD[T]): self.rdd = rdd [docs] def mapPartitions( self, f: Callable[[Iterable[T]], Iterable[U]], preservesPartitioning: bool = False ) -> RDD[U]: """ Returns a new RDD by applying a function to each partition of the wrapped RDD, where tasks are launched together in a barrier stage. The interface is the same as :meth:`RDD.mapPartitions`. Please see the API doc there. .. versionadded:: 2.4.0 Parameters ---------- f : function a function to run on each partition of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each partition See Also -------- :meth:`RDD.mapPartitions` Notes ----- This API is experimental Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 2) >>> def f(iterator): yield sum(iterator) >>> barrier = rdd.barrier() >>> barrier <pyspark.rdd.RDDBarrier ...> >>> barrier.mapPartitions(f).collect() [3, 7] """ def func(s: int, iterator: Iterable[T]) -> Iterable[U]: return f(iterator) return PipelinedRDD(self.rdd, func, preservesPartitioning, isFromBarrier=True) [docs] def mapPartitionsWithIndex( self, f: Callable[[int, Iterable[T]], Iterable[U]], preservesPartitioning: bool = False, ) -> RDD[U]: """ Returns a new RDD by applying a function to each partition of the wrapped RDD, while tracking the index of the original partition. And all tasks are launched together in a barrier stage. The interface is the same as :meth:`RDD.mapPartitionsWithIndex`. Please see the API doc there. .. versionadded:: 3.0.0 Parameters ---------- f : function a function to run on each partition of the RDD preservesPartitioning : bool, optional, default False indicates whether the input function preserves the partitioner, which should be False unless this is a pair RDD and the input Returns ------- :class:`RDD` a new :class:`RDD` by applying a function to each partition See Also -------- :meth:`RDD.mapPartitionsWithIndex` Notes ----- This API is experimental Examples -------- >>> rdd = sc.parallelize([1, 2, 3, 4], 4) >>> def f(splitIndex, iterator): yield splitIndex >>> barrier = rdd.barrier() >>> barrier <pyspark.rdd.RDDBarrier ...> >>> barrier.mapPartitionsWithIndex(f).sum() 6 """ return PipelinedRDD(self.rdd, f, preservesPartitioning, isFromBarrier=True) class PipelinedRDD(RDD[U], Generic[T, U]): """ Examples -------- Pipelined maps: >>> rdd = sc.parallelize([1, 2, 3, 4]) >>> rdd.map(lambda x: 2 * x).cache().map(lambda x: 2 * x).collect() [4, 8, 12, 16] >>> rdd.map(lambda x: 2 * x).map(lambda x: 2 * x).collect() [4, 8, 12, 16] Pipelined reduces: >>> from operator import add >>> rdd.map(lambda x: 2 * x).reduce(add) 20 >>> rdd.flatMap(lambda x: [x, x]).reduce(add) 20 """ def __init__( self, prev: RDD[T], func: Callable[[int, Iterable[T]], Iterable[U]], preservesPartitioning: bool = False, isFromBarrier: bool = False, ): if not isinstance(prev, PipelinedRDD) or not prev._is_pipelinable(): # This transformation is the first in its stage: self.func = func self.preservesPartitioning = preservesPartitioning self._prev_jrdd = prev._jrdd self._prev_jrdd_deserializer = prev._jrdd_deserializer else: prev_func: Callable[[int, Iterable[V]], Iterable[T]] = prev.func def pipeline_func(split: int, iterator: Iterable[V]) -> Iterable[U]: return func(split, prev_func(split, iterator)) self.func = pipeline_func self.preservesPartitioning = prev.preservesPartitioning and preservesPartitioning self._prev_jrdd = prev._prev_jrdd # maintain the pipeline self._prev_jrdd_deserializer = prev._prev_jrdd_deserializer self.is_cached = False self.has_resource_profile = False self.is_checkpointed = False self.ctx = prev.ctx self.prev = prev self._jrdd_val: Optional["JavaObject"] = None self._id = None self._jrdd_deserializer = self.ctx.serializer self._bypass_serializer = False self.partitioner = prev.partitioner if self.preservesPartitioning else None self.is_barrier = isFromBarrier or prev._is_barrier() def getNumPartitions(self) -> int: return self._prev_jrdd.partitions().size() @property def _jrdd(self) -> "JavaObject": if self._jrdd_val: return self._jrdd_val if self._bypass_serializer: self._jrdd_deserializer = NoOpSerializer() if ( self.ctx.profiler_collector and self.ctx._conf.get("spark.python.profile", "false") == "true" ): profiler = self.ctx.profiler_collector.new_profiler(self.ctx) else: profiler = None wrapped_func = _wrap_function( self.ctx, self.func, self._prev_jrdd_deserializer, self._jrdd_deserializer, profiler ) assert self.ctx._jvm is not None python_rdd = self.ctx._jvm.PythonRDD( self._prev_jrdd.rdd(), wrapped_func, self.preservesPartitioning, self.is_barrier ) self._jrdd_val = python_rdd.asJavaRDD() if profiler: assert self._jrdd_val is not None self._id = self._jrdd_val.id() self.ctx.profiler_collector.add_profiler(self._id, profiler) return self._jrdd_val def id(self) -> int: if self._id is None: self._id = self._jrdd.id() return self._id def _is_pipelinable(self) -> bool: return not (self.is_cached or self.is_checkpointed or self.has_resource_profile) def _is_barrier(self) -> bool: return self.is_barrier def _test() -> None: import doctest import tempfile from pyspark.context import SparkContext tmp_dir = tempfile.TemporaryDirectory() globs = globals().copy() # The small batch size here ensures that we see multiple batches, # even in these small test examples: globs["sc"] = SparkContext("local[4]", "PythonTest") globs["sc"].setCheckpointDir(tmp_dir.name) (failure_count, test_count) = doctest.testmod(globs=globs, optionflags=doctest.ELLIPSIS) globs["sc"].stop() tmp_dir.cleanup() if failure_count: tmp_dir.cleanup() sys.exit(-1) if __name__ == "__main__": _test()