performance - Which is the most efficient way to iterate through a list in python?

Question

Say I have a list of items:

x = [1, 2, 3, 4, 5]

I need to perform some functions for each of these items. In a certain case, I need to return the index of an item.

Which is the best and most efficient way?

for item in list:
    ....

or

for i in range(len(list)):
    ....

Answer 1

for item in list:

its obviously the one with fewer function calls.

If you want to get the index of items as you go use enumerate like this

for pos, item in enumerate(collection):