Python - Unique keys count for Value in Tuple List

When it is required to get the count of the unique values in a list of tuple, ‘defaultdict’, ‘set’ operator and the ‘append’ method are used.

Example

Below is a demonstration of the same −

from collections import defaultdict my_list = [(12, 32), (12, 21), (21, 32), (89, 21), (71, 21), (89, 11), (99, 10), (8, 23), (10, 23)] print("The list is :") print(my_list) my_result = defaultdict(list) for element in my_list:    my_result[element[1]].append(element[0]) my_result = dict(my_result) result_dictionary = dict() for key in my_result:    result_dictionary[key] = len(list(set(my_result[key]))) print("The resultant list is :") print(result_dictionary)

Output

The list is : [(12, 32), (12, 21), (21, 32), (89, 21), (71, 21), (89, 11), (99, 10), (8, 23), (10, 23)] The resultant list is : {32: 2, 21: 3, 11: 1, 10: 1, 23: 2}

Explanation

• The required packages are imported into the environment.

• A list of tuple is defined and is displayed on the console.

• An empty dictionary is created.

• The list is iterated over, and the second and first elements are appended to the dictionary.

• This list is again converted to a dictionary.

• Another empty dictionary is created.

• The list is iterated over, and unique elements are obtained using ‘set’ operator.

• It is converted to a list, and its length is assigned to a variable.

• This is the output that is displayed on the console.