问题
I have an RDD structure like:
rdd = [[[1],[2],[3]], [[4],[5]], [[6]], [[7],[8],[9],[10]]]
and I want it to become:
rdd = [1,2,3,4,5,6,7,8,9,10]
How do I write a map or reduce function to make it work?
回答1:
You can for example flatMap and use list comprehensions:
rdd.flatMap(lambda xs: [x[0] for x in xs])
or to make it a little bit more general:
from itertools import chain
rdd.flatMap(lambda xs: chain(*xs)).collect()
来源：https://stackoverflow.com/questions/34711149/how-to-flatten-nested-lists-in-pyspark