---
title: find_index_of_all
tags: list,intermediate
---

Returns the indexes of all elements in the provided 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`.

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

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