Python - Extract Key's value from Mixed Dictionaries List

Python – Extract Key’s value from Mixed Dictionaries List

Last Updated : 29 Aug, 2020

Given a list of dictionaries, with each dictionary having different keys, extract value of key K.

Input : test_list = [{“Gfg” : 3, “b” : 7}, {“is” : 5, ‘a’ : 10}, {“Best” : 9, ‘c’ : 11}], K = ‘b’
Output : 7
Explanation : Value of b is 7.
Input : test_list = [{“Gfg” : 3, “b” : 7}, {“is” : 5, ‘a’ : 10}, {“Best” : 9, ‘c’ : 11}], K = ‘c’
Output : 11
Explanation : Value of c is 11.

Method #1 : Using list comprehension

This is one of the ways in which this task can be performed. In this, we iterate for each dictionary inside list, and check for key in it, if present the required valu is returned.

Python3

# Python3 code to demonstrate working of 
# Extract Key's value from Mixed Dictionaries List
# Using list comprehension
  
# initializing list
test_list = [{"Gfg" : 3, "b" : 7}, 
             {"is" : 5, 'a' : 10}, 
             {"Best" : 9, 'c' : 11}]
  
# printing original list
print("The original list : " + str(test_list))
  
# initializing K 
K = 'Best'
  
# list comprehension to get key's value 
# using in operator to check if key is present in dictionary
res = [sub[K] for sub in test_list if K in sub][0]
  
# printing result 
print("The extracted value : " + str(res))

Output

The original list : [{'Gfg': 3, 'b': 7}, {'is': 5, 'a': 10}, {'Best': 9, 'c': 11}]
The extracted value : 9

Method #2 : Using update() + loop

This is yet another way in which this task can be performed. In this, we update each dictionary into each other. Forming one large dictionary, and then value is extracted from this dictionary.

Python3

# Python3 code to demonstrate working of 
# Extract Key's value from Mixed Dictionaries List
# Using update() + loop
  
# initializing list
test_list = [{"Gfg" : 3, "b" : 7}, 
             {"is" : 5, 'a' : 10}, 
             {"Best" : 9, 'c' : 11}]
  
# printing original list
print("The original list : " + str(test_list))
  
# initializing K 
K = 'Best'
  
res = dict()
for sub in test_list:
      
    # merging all Dictionaries into 1
    res.update(sub)
  
# printing result 
print("The extracted value : " + str(res[K]))

Output

The original list : [{'Gfg': 3, 'b': 7}, {'is': 5, 'a': 10}, {'Best': 9, 'c': 11}]
The extracted value : 9

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