30-seconds-of-code/snippets/deep_flatten.md

title, tags

title	tags
deep_flatten	list,recursion,intermediate

Deep flattens a list.

• Use recursion.
• Use isinstance() with collections.abc.Iterable to check if an element is iterable.
• If it is iterable, apply deep_flatten() recursively, otherwise return [lst].

from collections.abc import Iterable

def deep_flatten(lst):
  return ([a for i in lst for a in
          deep_flatten(i)] if isinstance(lst, Iterable) else [lst])

deep_flatten([1, [2], [[3], 4], 5]) # [1, 2, 3, 4, 5]