How to iterate over the first n elements of a list

Question

Say I've got a list and I want to iterate over the first n of them. What's the best way to write this in Python?

Answer 1

Python lists are O(1) random access, so just:

for i in xrange(n):
    print list[i]

Answer 2

You can just slice the list:

>>> l = [1, 2, 3, 4, 5]
>>> n = 3
>>> l[:n]
[1, 2, 3]

and then iterate on the slice as with any iterable.

Answer 3

I'd probably use itertools.islice (<- follow the link for the docs), which has the benefit of working with any iterable object.

Answer 4

The normal way would be slicing:

for item in your_list[:n]: 
    ...