Python – Cross mapping of Two dictionary value lists

Python Server Side Programming Programming

When it is required to cross-map two dictionary valued lists, the ‘setdefault’ and ‘extend’ methods are used.

Example

Below is a demonstration of the same −

my_dict_1 = {"Python" : [4, 7], "Fun" : [8, 6]}
my_dict_2 = {6 : [5, 7], 8 : [3, 6], 7 : [9, 8]}

print("The first dictionary is : " )
print(my_dict_1)

print("The second dictionary is : " )
print(my_dict_2)

sorted(my_dict_1.items(), key=lambda e: e[1][1])
print("The first dictionary after sorting is ")
print(my_dict_1)

sorted(my_dict_2.items(), key=lambda e: e[1][1])
print("The second dictionary after sorting is ")
print(my_dict_2)

my_result = {}
for key, value in my_dict_1.items():
   for index in value:
      my_result.setdefault(key, []).extend(my_dict_2.get(index, []))

print("The resultant dictionary is : ")
print(my_result)

Output

The first dictionary is :
{'Python': [4, 7], 'Fun': [8, 6]}
The second dictionary is :
{6: [5, 7], 8: [3, 6], 7: [9, 8]}
The first dictionary after sorting is
{'Python': [4, 7], 'Fun': [8, 6]}
The second dictionary after sorting is
{6: [5, 7], 8: [3, 6], 7: [9, 8]}
The resultant dictionary is :
{'Python': [9, 8], 'Fun': [3, 6, 5, 7]}

Explanation

Two dictionaries are defined and is displayed on the console.
They are sorted using ‘sorted’ method and lambda method and displayed on the console.
An empty dictionary is created.
The dictionary is iterated over, and the key is set to a default value.
The index of the elements in the second dictionary is obtained and added to empty dictionary using the ‘extend’ method.
This is the output that is displayed on the console.

AmitDiwan

Published on 13-Sep-2021 07:35:34

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