examples/src/main/python/mllib/stratified_sampling_example.py

#
# Licensed to the Apache Software Foundation (ASF) under one or more
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# 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
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#
#    http://www.apache.org/licenses/LICENSE-2.0
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from pyspark import SparkContext

if __name__ == "__main__":
    sc = SparkContext(appName="StratifiedSamplingExample")  # SparkContext

    # $example on$
    # an RDD of any key value pairs
    data = sc.parallelize([(1, 'a'), (1, 'b'), (2, 'c'), (2, 'd'), (2, 'e'), (3, 'f')])

    # specify the exact fraction desired from each key as a dictionary
    fractions = {1: 0.1, 2: 0.6, 3: 0.3}

    approxSample = data.sampleByKey(False, fractions)
    # $example off$

    for each in approxSample.collect():
        print(each)

    sc.stop()