Python - Assign Frequency to Tuples

Python – Assign Frequency to Tuples

Last Updated : 02 Sep, 2020

Given tuple list, assign frequency to each tuple in list.

Input : test_list = [(6, 5, 8), (2, 7), (6, 5, 8), (9, ), (2, 7)]
Output : [(6, 5, 8, 2), (2, 7, 2), (9, 1)]
Explanation : (2, 7) occurs 2 times, hence 2 is appened in tuple.
Input : test_list = [(2, 7), (2, 7), (6, 5, 8), (9, ), (2, 7)]
Output : [(6, 5, 8, 1), (2, 7, 3), (9, 1)]
Explanation : (2, 7) occurs 3 times, hence 3 is appened in tuple.

Method #1 : Using Counter() + items() + * operator + list comprehension

In this, we extract the frequency using Counter(), fetch frequency numbers using items(), * operator is used to unpack elements and list comprehension is used to assign this to all elements in tuple list.

Python3

# Python3 code to demonstrate working of 
# Assign Frequency to Tuples
# Using Counter() + items() + * operator + list comprehension
from collections import Counter
  
# initializing list
test_list = [(6, 5, 8), (2, 7), (6, 5, 8), (6, 5, 8), (9, ), (2, 7)]
  
# printing original list
print("The original list is : " + str(test_list))
  
# one-liner to solve problem
# assign Frequency as last element of tuple
res = [(*key, val) for key, val in Counter(test_list).items()]
  
# printing results
print("Frequency Tuple list : " + str(res))

Output

The original list is : [(6, 5, 8), (2, 7), (6, 5, 8), (6, 5, 8), (9, ), (2, 7)]
Frequency Tuple list : [(6, 5, 8, 3), (2, 7, 2), (9, 1)]

Method #2 : Using most_common() + Counter() + * operator + list comprehension

This is similar to the above method, just most_common() performs sort operation on list, which is not necessary.

Python3

# Python3 code to demonstrate working of 
# Assign Frequency to Tuples
# Using most_common() + Counter() + * operator + list comprehension
from collections import Counter
  
# initializing list
test_list = [(6, 5, 8), (2, 7), (6, 5, 8), (6, 5, 8), (9, ), (2, 7)]
  
# printing original list
print("The original list is : " + str(test_list))
  
# most_common performs sort on arg. list
# assign Frequency as last element of tuple
res = [(*key, val) for key, val in Counter(test_list).most_common()]
  
# printing results
print("Frequency Tuple list : " + str(res))

Output

The original list is : [(6, 5, 8), (2, 7), (6, 5, 8), (6, 5, 8), (9, ), (2, 7)]
Frequency Tuple list : [(6, 5, 8, 3), (2, 7, 2), (9, 1)]

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