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

title, tags, expertise, firstSeen, lastUpdated

title	tags	expertise	firstSeen	lastUpdated
Flatten list	list	intermediate	2019-09-19T15:46:10+03:00	2020-11-02T19:27:53+02:00

Flattens a list of lists once.

• Use a list comprehension to extract each value from sub-lists in order.

def flatten(lst):
  return [x for y in lst for x in y]

flatten([[1, 2, 3, 4], [5, 6, 7, 8]]) # [1, 2, 3, 4, 5, 6, 7, 8]