list.sort
Sort the list in place.
Python 3.13
list.sort(*, key=None, reverse=False)Parameters
- keyCallable | Noneoptional
- A function whose result is used to compare items, such as len or str.lower.
- reversebooloptional
- If True, sorts in descending order.
Return value
Nothing (None); the list is sorted in place.
Examples
Sorting a list in place
Python 3.13
a = [3, 1, 2]
a.sort()
print(a)[1, 2, 3]
Case-insensitive sorting
Python 3.13
words = ['banana', 'Kiwi', 'apple']
words.sort(key=str.lower)
print(words)['apple', 'banana', 'Kiwi']
Details
A common mistake is a = a.sort(): the method returns None, and the list is lost. To keep the original order, use sorted.