Question

Given a boolean list such as [True, False, False, True, False, True], what is the quickest way to get a list/tuple containing the indexes (starting from 1, not zero-indexed) of the Truthy elements in the original list? So for the list above, it should returns [1, 4, 6] or (1, 4, 6).

I was using a generator like this:

def get_truthy_ones(self, bool_list):
    return (idx + 1 for idx, value in enumerate(bool_list) if value)

However, this creates a problem when I want to encode the results in a JSON object, as JSON does not encode generators.

Answer 1

[i for i, elem in enumerate(bool_list, 1) if elem]