find-last-index.md

title	type	tags	cover	dateModified
Find last matching index	snippet	list	succulent-8	2020-11-02 19:27:53 +0200

Finds the index of the last element in the given list that satisfies the provided testing function.

• Use a list comprehension, enumerate() and next() to return the index of the last element in lst for which fn returns True.

def find_last_index(lst, fn):
  return len(lst) - 1 - next(i for i, x in enumerate(lst[::-1]) if fn(x))

find_last_index([1, 2, 3, 4], lambda n: n % 2 == 1) # 2