# Find matching index

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