Python List sort() method

• Difficulty Level : Easy
• Last Updated : 03 Aug, 2021

Python list sort() function can be used to sort a List in ascending, descending, or user-defined order.

To Sort the List in Ascending Order

Syntax:

List_name.sort()

This will sort the given list in ascending order. This function can be used to sort a list of integers, floating-point numbers, strings, and others.

Python3

 numbers = [1, 3, 4, 2]  # Sorting list of Integers in ascendingnumbers.sort()  print(numbers)

Output:

[1, 2, 3, 4]

Python3

 strs = ["geeks", "code", "ide", "practice"]  # Sorting list of Integers in ascendingstrs.sort()  print(strs)

Output:

['code', 'geeks', 'ide', 'practice']

To Sort the List in Descending Order

Syntax:

list_name.sort(reverse=True)

This will sort the given list in descending order.

Python3

 numbers = [1, 3, 4, 2]  # Sorting list of Integers in descendingnumbers.sort(reverse = True)  print(numbers)

Output:

[4, 3, 2, 1]

Sorting Using User-defined Order

Syntax:

list_name.sort(key=…, reverse=…) – it sorts according to user’s choice

Parameters:

• reverse: reverse=True will sort the list descending. Default is reverse=False
• key: A function to specify the sorting criteria(s)

Python

 # Python program to demonstrate sorting by user's# choice  # function to return the second element of the# two elements passed as the parameterdef sortSecond(val):    return val   # list1 to demonstrate the use of sorting # using using second key list1 = [(1, 2), (3, 3), (1, 1)]  # sorts the array in ascending according to # second elementlist1.sort(key = sortSecond) print(list1)  # sorts the array in descending according to# second elementlist1.sort(key = sortSecond, reverse = True)print(list1)

Output:

[(1, 1), (1, 2), (3, 3)]
[(3, 3), (1, 2), (1, 1)]

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