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 retu

Answer 1

Obviously for i in range(len(list)): will be slower - in python 2, it's equivalent to this:

list2 = range(len(list))

for i in list2:
    ...

If that were faster, then this would be even faster, right?

list2 = range(len(list))
list3 = range(len(list2))
list4 = range(len(list3))

for i in list4:
    ...