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Python Program to Remove Nth element from Kth key’s value from the dictionary
  • Last Updated : 02 Feb, 2021

Given a dictionary with value lists, our task is to write a Python program to remove N element from Kth key’s values.

Examples:

Input : test_dict = {“gfg” : [9, 4, 5, 2, 3, 2], “is” : [1, 2, 3, 4, 3, 2], “best” : [2, 2, 2, 3, 4]}, K, N = “gfg”, 2

Output : {‘gfg’: [9, 4, 5, 3], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}

Explanation : 2 removed from “gfg” key’s value list.



Input : test_dict = {“gfg” : [9, 4, 5, 2, 3, 2], “is” : [1, 2, 3, 4, 3, 2], “best” : [2, 2, 2, 3, 4]}, K, N = “gfg”, 4

Output : {‘gfg’: [9, 5, 2, 3, 2], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}

Explanation : 4 removed from “gfg” key’s value list.

Method #1 : Using loop + conditional statements

In this, reassignment of all the key along with their values is done, when K key occurs, N’s occurrence from its value list is omitted.

Python3




# Python3 code to demonstrate working of
# Remove N from K key's value in dictionary values list
# Using loop + conditional statements
  
# initializing dictionary
test_dict = {"gfg" : [9, 4, 5, 2, 3, 2],
             "is" : [1, 2, 3, 4, 3, 2],
             "best" : [2, 2, 2, 3, 4]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing K, N 
K, N = "gfg", 2
  
res = dict()
for key, val in test_dict.items():
      
    # reassigning omitting desired number
    res[key] = (val if key != K else [idx for idx in val if idx != N])
  
# printing result
print("The altered dictionary : " + str(res))

Output:

The original dictionary is : {‘gfg’: [9, 4, 5, 2, 3, 2], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}

The altered dictionary : {‘gfg’: [9, 4, 5, 3], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}



Method #2 : Using dictionary comprehension

In this, we perform similar task to above method, difference being use of dictionary comprehension instead of looping through keys using conventional loop.

Python3




# Python3 code to demonstrate working of
# Remove N from K key's value in dictionary values list
# Using dictionary comprehension
  
# initializing dictionary
test_dict = {"gfg" : [9, 4, 5, 2, 3, 2],
             "is" : [1, 2, 3, 4, 3, 2], 
             "best" : [2, 2, 2, 3, 4]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing K, N 
K, N = "gfg", 2
  
# dictionary comprehension used for shorthand
res = {key : (val if key != K else [idx for idx in val if idx != N]) for key, val in test_dict.items()}
  
# printing result
print("The altered dictionary : " + str(res))

Output:

The original dictionary is : {‘gfg’: [9, 4, 5, 2, 3, 2], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}

The altered dictionary : {‘gfg’: [9, 4, 5, 3], ‘is’: [1, 2, 3, 4, 3, 2], ‘best’: [2, 2, 2, 3, 4]}

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