Lists

Understanding Python's sort() Method¶

Let's start with a surprising example:

numbers = [3, 2, 4, 5, 1]

sorted_numbers = numbers.sort()
# THIS WILL OUTPUT None
print(sorted_numbers)  # Output: None

In this example, the output is None. Surprised and expected [1,2,3,4,5]?.

Let's find out what happens in the backend¶

The sort() method sorts a list without creating a new list.

The sort() method sorts the elements of a list in place, meaning it modifies the original list directly without creating a new list. It does not return a new sorted list, but rather updates the existing list and returns None.

This is the key difference between the sort() method and the sorted() function. The sorted() function returns a new list that is sorted, while the sort() method sorts the list it is called on and does not create a new list.

Let's see some examples¶

Example 1: Using sort() method

numbers = [3, 2, 4, 5, 1]

numbers.sort()

print(numbers)  # Output: [1, 2, 3, 4, 5]

Example 2: Using sorted() function

numbers = [3, 2, 4, 5, 1]

sorted_numbers = sorted(numbers)

print(sorted_numbers)  # Output: [1, 2, 3, 4, 5]
print(numbers)  # Output: [3, 2, 4, 5, 1]

Sorting in reverse order¶

sorted_numbers = sorted(numbers, reverse=True)