The sort() method of list class rearranges the items in ascending or descending order with the use of lexicographical ordering mechanism. The sorting is in-place, in the sense the rearrangement takes place in the same list object, and that it doesn't return a new object.
Syntax
Parameters
-
Key − The function applied to each item in the list. The return value is used to perform sort. Optional
-
reverse − Boolean value. If set to True, the sort takes place in descending order. Optional
Return value
This method returns None.
Example 1
Now let's take a look at some examples to understand how we can sort lists in Python −
It will produce the following output −
list before sort ['physics', 'Biology', 'chemistry', 'maths'] list after sort: ['Biology', 'chemistry', 'maths', 'physics'] Descending sort list before sort [10, 16, 9, 24, 5] list after sort : [5, 9, 10, 16, 24]
Example 2
In this example, the str.lower() method is used as key parameter in sort() method.
It will produce the following output −
list before sort ['Physics', 'biology', 'Biomechanics', 'psychology'] list after sort : ['biology', 'Biomechanics', 'Physics', 'psychology']
Example 3
Let us use a user-defined function as the key parameter in sort() method. The myfunction() uses % operator to return the remainder, based on which the sort is done.
It will produce the following output −
list before sort [17, 23, 46, 51, 90] list after sort: [90, 51, 23, 46, 17]