Given a list, extract all the elements having same frequency as its value.
Examples:
Input : test_list = [4, 3, 2, 2, 3, 4, 1, 3, 2, 4, 4]
Output : [1, 3, 4]
Explanation : All elements occur equal times as their value.
Input : test_list = [4, 3, 2, 2, 3, 4, 1, 3, 2, 4]
Output : [1, 3]
Explanation : All elements occur equal times as their value.
Method #1 : Using list comprehension + count()
In this, task of getting frequency is done using count(), list comprehension is used to iterate for each element, compare and extract.
Python3
# Python3 code to demonstrate working of # Extract elements with equal frequency as value# Using list comprehension + count() # initializing listtest_list = [4, 3, 2, 2, 3, 4, 1, 3, 2, 4, 4] # printing original listprint("The original list is : " + str(test_list)) # removing duplicates using set()# count() for computing frequencyres = list(set([ele for ele in test_list if test_list.count(ele) == ele])) # printing result print("Filtered elements : " + str(res)) |
The original list is : [4, 3, 2, 2, 3, 4, 1, 3, 2, 4, 4] Filtered elements : [1, 3, 4]
Method #2 : Using filter() + lambda + count()
In this, we perform task of filtering elements using filter() and lambda, count() again is used to get count of all the elements.
Python3
# Python3 code to demonstrate working of # Extract elements with equal frequency as value# Using filter() + lambda + count() # initializing listtest_list = [4, 3, 2, 2, 3, 4, 1, 3, 2, 4, 4] # printing original listprint("The original list is : " + str(test_list)) # removing duplicates using set()# count() for computing frequency# filter used to perform filtering res = list(set(list(filter(lambda ele : test_list.count(ele) == ele, test_list)))) # printing result print("Filtered elements : " + str(res)) |
The original list is : [4, 3, 2, 2, 3, 4, 1, 3, 2, 4, 4] Filtered elements : [1, 3, 4]
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