Python : Sort a List of numbers in Descending or Ascending Order | list.sort() vs sorted()

In this article we will discuss how to sort a list of numbers in ascending and descending order using two different techniques.

list.sort() vs sorted()

list’s sort() function

In Python, list provides a member function sort() that can sorts the calling list in place.

sorted() Function

It’s a built in function that accepts an iterable objects and a new sorted list from that iterable.

Let’s use both to sort a list of numbers in ascending and descending Order

Suppose we have a list of number’s i.e.

# List of numbers
listOfNum = [23, 45, 21, 45, 2, 5, 11, 50, 1, 67]

Sorting the List in ascending Order using sorted()

# Create a sorted copy of existing list
newList = sorted(listOfNum)

It will create a newList with sorted numbers in ascending order i.e.

newList
[1, 2, 5, 11, 21, 23, 45, 45, 50, 67]

Whereas, existing list will not change

listOfNum
[23, 45, 21, 45, 2, 5, 11, 50, 1, 67]

Sorting the List in ascending Order using list.sort()

# Sort the List in Place
listOfNum.sort()

It will sort the list itself.

listOfNum is now a  List Sorted in Ascending Order

[1, 2, 5, 11, 21, 23, 45, 45, 50, 67]

Sorting the List in Descending Order using sorted()

# Create a sorted (Descending Order) copy of existing list
newList = sorted(listOfNum, reverse=True)

It will create a newList with sorted numbers in Descending order i.e.

newList
[67, 50, 45, 45, 23, 21, 11, 5, 2, 1]

Whereas, existing list will not change

listOfNum
[23, 45, 21, 45, 2, 5, 11, 50, 1, 67]

Sorting the List in Descending Order using list.sort()

# Sort the List in Place (Descending Order)
listOfNum.sort(reverse=True)

It will sort the list itself.

listOfNum is now a  List Sorted in Descending Order

[67, 50, 45, 45, 23, 21, 11, 5, 2, 1]

Complete example is as follows,

def main():

    # List of numbers
    listOfNum = [23, 45, 21, 45, 2, 5, 11, 50, 1, 67]
    
    
    # print the List
    print("Initial List", listOfNum,  sep='\n')
        
    
    print("Sorting the List in ascending Order")
    
    # Create a sorted copy of existing list
    newList = sorted(listOfNum)
     # print the List
    print("New List", newList,  sep='\n')
     # print the List
    print("Existing List", listOfNum,  sep='\n')
    
    # Sort the List in Place
    listOfNum.sort()

    # print the List
    print("List Sorted in Ascending Order", listOfNum,  sep='\n')

    print("Sorting the List in Descending Order")
    
    # Create a sorted copy of existing list
    newList = sorted(listOfNum, reverse=True)
     # print the List
    print("New List", newList,  sep='\n')
     # print the List
    print("Existing List", listOfNum,  sep='\n')
    
    # Sort the List in Place (Descending Order)
    listOfNum.sort(reverse=True)

    # print the List
    print("List Sorted in Descending Order", listOfNum,  sep='\n')


if __name__ == "__main__":
    main()
    

Output:

Initial List
[23, 45, 21, 45, 2, 5, 11, 50, 1, 67]
Sorting the List in ascending Order
New List
[1, 2, 5, 11, 21, 23, 45, 45, 50, 67]
Existing List
[23, 45, 21, 45, 2, 5, 11, 50, 1, 67]
List Sorted in Ascending Order
[1, 2, 5, 11, 21, 23, 45, 45, 50, 67]
Sorting the List in Descending Order
New List
[67, 50, 45, 45, 23, 21, 11, 5, 2, 1]
Existing List
[1, 2, 5, 11, 21, 23, 45, 45, 50, 67]
List Sorted in Descending Order
[67, 50, 45, 45, 23, 21, 11, 5, 2, 1]