Find all matching indexes

Isabelle Viktoria Maciohsek · Python, List · Nov 2, 2020

Finds the indexes of all elements in the given list that satisfy the provided testing function.

• Use enumerate() and a list comprehension to return the indexes of the all element in lst for which fn returns True.

def find_index_of_all(lst, fn):
  return [i for i, x in enumerate(lst) if fn(x)]

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

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