Python | Clearing list as dictionary value

Clearing a list is a common problem and solution to it has been discussed many times. But sometimes, we don’t have a native list but list is a value to dictionary key. Clearing it is not as easy as clearing an original list. Let’s discuss certain ways in which this can be done.

Method #1 : Using loop + clear()
This is the most generic method in which we can perform this particular function. We just run a loop till the last dictionary key and clear the key’s list value as they occur using clear function.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 code to demonstrate
# clearing list as dict. value
# using loop + clear()
  
# initializing dict.
test_dict = {"Akash" : [1, 4, 3],
             "Nikhil" : [3, 4, 1],
             "Akshat" : [7, 8]}
  
# printing original dict
print("The original dict : " + str(test_dict))
  
# using loop + clear()
# clearing list as dict. value
for key in test_dict:
    test_dict[key].clear()
  
# print result
print("The dictionary after clearing value list : " + str(test_dict))

chevron_right






                        filter_none









Output :          



The original dict : {‘Nikhil’: [3, 4, 1], ‘Akshat’: [7, 8], ‘Akash’: [1, 4, 3]}

The dictionary after clearing value list : {‘Nikhil’: [], ‘Akshat’: [], ‘Akash’: []}





 




Method #2 : Using dictionary comprehension

We can reduce the lines of code and merge the above functionality using just the dictionary comprehension and clearing the list using the list re-initialization.











                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















# Python3 code to demonstrate 


# clearing list as dict. value 


# using dictionary comprehension 


  


# initializing dict. 


test_dict = {"Akash" : [1, 4, 3], 


             "Nikhil" : [3, 4, 1], 


             "Akshat" : [7, 8]} 


  


# printing original dict 


print("The original dict : " + str(test_dict)) 


  


# using dictionary comprehension 


# clearing list as dict. value 


test_dict = {key : [] for key in test_dict} 


  


# print result 


print("The dictionary after clearing value list : " + str(test_dict)) 



















                        chevron_right







                        filter_none









Output :          



The original dict : {‘Nikhil’: [3, 4, 1], ‘Akshat’: [7, 8], ‘Akash’: [1, 4, 3]}

The dictionary after clearing value list : {‘Nikhil’: [], ‘Akshat’: [], ‘Akash’: []}








    

        My Personal Notes
        arrow_drop_up
    

    

        
        

            
            
        

    


Recommended Posts:
manjeet_04
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.