Python List sort() Method (with Examples)

By IncludeHelp Last updated : June 20, 2023

Python List sort() Method

The sort() is an inbuilt method of the list class that is used to sort the list elements in ascending and descending order, the method is called with this list (whose elements are to be sorted) and accepts some optional parameters (explained below under parameters), the method does not return any value, it sorts this list.

Syntax

The following is the syntax of sort() method:

List_name.sort(reverse=True|False, key=function)

Parameter(s):

The following are the parameter(s):

reverse=True|False – It is an optional parameter, it's default value is False which sorts list elements in ascending order, if we set True, it sorts the list elements in descending order.
key=function – It is also an optional parameter, it can be used to specify the sorting criteria.

Return Value

The return type of this method is <class 'NoneType'>, it returns nothing.

Example 1: Sorting list without specifying any parameter

# declaring the list
cars = ["BMW", "Porsche", "Audi", "Lexus", "Audi"]

# printing the list
print("cars before sort operation...")
print("cars: ", cars)

# sorting the elements
cars.sort() # sorts in ascending order

# printing the list
print("cars after sort operation...")
print("cars: ", cars)

Output

cars before sort operation...
cars:  ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars after sort operation...
cars:  ['Audi', 'Audi', 'BMW', 'Lexus', 'Porsche']

Example 2: Sorting list with specifying the first parameter

# declaring the list
cars = ["BMW", "Porsche", "Audi", "Lexus", "Audi"]

# printing the list
print("cars before sort operation...")
print("cars: ", cars)

# sorting the elements specifying reverse=True
cars.sort(reverse=True) 

# printing the list
print("cars list elements in descending order...")
print("cars: ", cars)

# sorting the elements specifying reverse=False
cars.sort(reverse=False) 

# printing the list
print("cars list elements in ascending order...")
print("cars: ", cars)

Output

cars before sort operation...
cars:  ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars list elements in descending order...
cars:  ['Porsche', 'Lexus', 'BMW', 'Audi', 'Audi']
cars list elements in ascending order...
cars:  ['Audi', 'Audi', 'BMW', 'Lexus', 'Porsche']

Example 3: Sorting list with specifying the both parameters

# defining a function that will return length
def getLen(e):
    return len(e)
    
# declaring the list
cars = ["BMW", "Porsche", "Audi", "Lexus", "Audi"]

# printing the list
print("cars before sort operation...")
print("cars: ", cars)

# sorting the elements specifying reverse=True
cars.sort(reverse=True,key=getLen) 

# printing the list
print("cars list elements in descending order based on length...")
print("cars: ", cars)

# sorting the elements specifying reverse=False
cars.sort(reverse=False,key=getLen) 

# printing the list
print("cars list elements in ascending order based on length...")
print("cars: ", cars)

Output

cars before sort operation...
cars:  ['BMW', 'Porsche', 'Audi', 'Lexus', 'Audi']
cars list elements in descending order based on length...
cars:  ['Porsche', 'Lexus', 'Audi', 'Audi', 'BMW']
cars list elements in ascending order based on length...
cars:  ['BMW', 'Audi', 'Audi', 'Lexus', 'Porsche']

Python List reverse() Method

Python List append() Vs. insert() Methods