CODESARRAY

Short note, by Codesarray, , 2 min read

Python negative indexing: get the last item with nums[-1]

A negative index counts from the end of a Python list, so nums[-1] is always the last item, with no len() needed.

To get the last item of a Python list, use negative indexing: nums[-1]. You do not need the length of the list, and it works however long the list is.

Count back from the end

nums = [10, 20, 30, 40]
print(nums[-1])
print(nums[-2])
print(nums[-4])
40
30
10

Negative positions count from the end, starting at -1. So nums[-1] is the last item, nums[-2] is the one before it, and nums[-4] is the first item of this four-item list.

What happens past the start

nums[-5] is one step too far for a list of four, so Python raises IndexError: list index out of range. The same error appears for any index that points outside the list.

Things to know

  • nums[-1] does the same job as nums[len(nums) - 1], with less to type and less to get wrong.
  • It works on strings and tuples too: "abc"[-1] is 'c'.
  • On an empty list, [][-1] raises IndexError, because there is no last item.

This is a short note on Lists, lesson 5 of the Python beginner track.

This article goes with the video Negative indexing in Python. Watch it on YouTube.