pyspark.RDD.takeOrdered

RDD.takeOrdered(num, key=None)

Get the N elements from an RDD ordered in ascending order or as specified by the optional key function.

New in version 1.0.0.

Parameters

numint

top N

keyfunction, optional

a function used to generate key for comparing

Returns

list

the top N elements

See also

RDD.top()

RDD.max()

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)
[]