Python program to update a dictionary with the values from a dictionary list

Given a dictionary and dictionary list, update the dictionary with dictionary list values.

Input : test_dict = {“Gfg” : 2, “is” : 1, “Best” : 3}, dict_list = [{‘for’ : 3, ‘all’ : 7}, {‘and’ : 1, ‘CS’ : 9}] 
Output : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3, ‘for’: 3, ‘all’: 7, ‘and’: 1, ‘CS’: 9} 
Explanation : All dictionary keys updated in single dictionary.

Input : test_dict = {“Gfg” : 2, “is” : 1, “Best” : 3}, dict_list = [{‘for’ : 3, ‘all’ : 7}] 
Output : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3, ‘for’: 3, ‘all’: 7} 
Explanation : All dictionary keys updated in single dictionary. 

Method #1 : Using update() + loop

In this, we iterate through all the elements in loop, and perform update to update all the keys in dictionary to original dictionary.

Output:

The original dictionary is : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3} 
 

The updated dictionary : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3, ‘for’: 3, ‘all’: 7, ‘geeks’: 10, ‘and’: 1, ‘CS’: 9}

Method #2 : Using ChainMap + ** operator

In this, we perform task of merging all list dictionaries into 1 using ChainMap and ** operator is used to merge target dictionary to merged dictionary.

Output:

The original dictionary is : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3}

The updated dictionary : {‘Gfg’: 2, ‘is’: 1, ‘Best’: 3, ‘for’: 3, ‘all’: 7, ‘geeks’: 10, ‘and’: 1, ‘CS’: 9}