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

title, tags

title	tags
find_index	list,beginner

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

Use 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