Python | Get last element of each sublist

Given a list of lists, write a Python program to extract the last element of each sublist in the given list of lists.

Examples:

Input : [[1, 2, 3], [4, 5], [6, 7, 8, 9]]
Output : [3, 5, 9]

Input : [['x', 'y', 'z'], ['m'], ['a', 'b'], ['u', 'v']]
Output : ['z', 'm', 'b', 'v']

Approach #1 : List comprehension

# Python3 program to extract first and last  
# element of each sublist in a list of lists 
  
def Extract(lst): 
    return [item[-1] for item in lst] 
      
# Driver code 
lst = [[1, 2, 3], [4, 5], [6, 7, 8, 9]] 
print(Extract(lst)) 

Output:

[3, 5, 9]

Approach #2 : Using zip and unpacking(*) operator

This method uses zip with * or unpacking operator which passes all the items inside the ‘lst’ as arguments to zip function. There is a little trick with extracting last item of list, Instead of using direct zip, use the reversed list iterators.

   
# Python3 program to extract first and last  
# element of each sublist in a list of lists 
  
def Extract(lst): 
    return list(zip(*[reversed(el) for el in lst]))[0] 
      
# Driver code 
lst = [[1, 2, 3], [4, 5], [6, 7, 8, 9]] 
print(Extract(lst)) 

Output:

(3, 5, 9)

Another way of using zip is to use it with Python map, passing reversed as function.

def Extract(lst): 
    return list(list(zip(*map(reversed, lst)))[0]) 

Approach #3 : Using itemgetter()

# Python3 program to extract first and last  
# element of each sublist in a list of lists 
from operator import itemgetter 
  
def Extract(lst): 
    return list( map(itemgetter(-1), lst )) 
      
# Driver code 
lst = [[1, 2, 3], [4, 5], [6, 7, 8, 9]] 
print(Extract(lst)) 

Output:

[3, 5, 9]

My Personal Notes

Recommended Posts:

Smitha Dinesh Semwal

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Suggest a Topic

Recommended Posts: