Python List sort() method

The list.sort () method in Python sorts the items of the list in place.

Syntax

list.sort(key=None, reverse=False)

Parameter

reverse: If a Boolean value ‘True’ is passed, the  sorting will be done in the descending order else for ‘False’ Boolean value sorting is done in ascending order.

key: This parameter represents a function to specify the sorting criteria(s)

Example 1

# Python program explaining
# the list.sort() method
# passing the alphabets list
alphaList = ['b', 'a', 'e', 'd', 'c']
print("Actual list: ",alphaList)
# sort the alphabets list in the ascending order 
alphaList.sort()
# priningt the list in a sorted order
print('Sorted list:',alphaList) 

Output

List:  ['b', 'a', 'e', 'd', 'c']
Sorted list: ['a', 'b', 'c', 'd', 'e'] 

Example 2

# Python program explaining
# the list.sort() method
weekList = ['Sun', 'Thurs', 'Mon', 'Fri', 'Tues', 'Wed']
print("Actual week list: ",weekList) 
# Sorting the week list in the descending order
weekList.sort(reverse=True)
# printing the sorted week list
print("Sorted week list:",weekList) 

Output

Actual week list:  ['Sun', 'Thurs', 'Mon', 'Fri', 'Tues', 'Wed']
Sorted week list: ['Wed', 'Tues', 'Thurs', 'Sun', 'Mon', 'Fri'] 

Example 3

# Python program explaining
# the list.sort() method
# returning the second element of the parameter 
def sortArray(arr): 
     return arr[1]   
# demonstrating the use of sorting by using using the second key  
valList = [(11, 12), (13, 13), (11, 11)] 
# sorting the array in ascending
valList.sort(key = sortArray, reverse = False)
# printing the sorted array
print("Sorted array in ascending order: \n",valList) 
# sorting the array in descending  
valList.sort(key = sortArray, reverse = True) 
# printing the sorted array
print("Sorted array in descending order: \n",valList)  

Output

Sorted array in ascending order: 
 [(11, 11), (11, 12), (13, 13)]
 Sorted array in descending order: 
 [(13, 13), (11, 12), (11, 11)]