30-seconds-of-code/snippets/find-index.md

title, tags, cover, firstSeen, lastUpdated

title	tags	cover	firstSeen	lastUpdated
Find matching index	list	book-chair	2020-03-10T22:38:48+02:00	2020-11-02T19:27:53+02:00

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

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

def find_index(lst, fn):
  return next(i for i, x in enumerate(lst) if fn(x))

find_index([1, 2, 3, 4], lambda n: n % 2 == 1) # 0