Proper Way to Shift Integer Into List Index Range

I need to retrieve the item at index i from list l. However, sometimes i falls outside of the range of the list index and throws an IndexError. I need to shift i to always be inside the range of the list index by leaps of len(l). The following code achieves just that.

l = ['a', 'b', 'c', 'd', 'e']

i = 6

while i >= len(l):
    i -= len(l)
while i < 0:
    i += len(l)

item = l[i] # item = 'b'

For my use case, i never falls more than len(l) out of range in either direction, so I’m able to shorten to this one liner by using if statements instead of while statements.

l = ['a', 'b', 'c', 'd', 'e']

i = -3

i = i-len(l) if i >= len(l) else i+len(l) if i < 0 else i

item = l[i] # item = 'c'

I’m thinking there must be some builtin function that achieves just this result, without a long, logical sentence. Is there a proper way to do this?

>Solution :

Seems like a perfect use case for the modulo operator.

item = l[i % len(l)]