List Methods

sort()

Sort the elements of the list in ascending or custom order.

list.sort(key=None, reverse=False)

list.sort() sorts the list in place using Python's Timsort algorithm (stable O(n log n)).

You can customize the sorting logic with a key transformation function and sort in descending order with reverse=True.

Parameters

Name	Description
key	Optional one-argument function used to extract a comparison key from each element (e.g. `len`, `str.lower`).
reverse	Optional boolean. If `True`, sorts the list in descending order (defaults to `False`).

Returns

None — the list is sorted in place.

Try it

Run it and change it

words = ["banana", "pie", "apple", "strawberry"]
words.sort(key=len)
print("Sorted by length:", words)
words.sort(reverse=True)
print("Alphabetical reverse:", words)

Worth knowing

sort() vs sorted(): list.sort() mutates the list in place and returns None. The built-in sorted(iterable) returns a brand new sorted list.
Stability: Python's sort is guaranteed to be stable — elements with equal keys maintain their original relative order.

Related entries

sorted()reverse()