Python - Extract elements with Frequency greater than K

Python – Extract elements with Frequency greater than K

Last Updated : 02 Sep, 2020

Given a List, extract all elements whose frequency is greater than K.

Input : test_list = [4, 6, 4, 3, 3, 4, 3, 4, 3, 8], K = 3
Output : [4, 3]
Explanation : Both elements occur 4 times.
Input : test_list = [4, 6, 4, 3, 3, 4, 3, 4, 6, 6], K = 2
Output : [4, 3, 6]
Explanation : Occur 4, 3, and 3 times respectively.

Method #1 : Using count() + loop

In this, we use count() to get the frequency, and loop is used to iterate for each of elements of List.

Python3

# Python3 code to demonstrate working of 
# Extract elements with Frequency greater than K
# Using count() + loop
  
# initializing list
test_list = [4, 6, 4, 3, 3, 4, 3, 7, 8, 8]
  
# printing string
print("The original list : " + str(test_list))
  
# initializing K 
K = 2
  
res = [] 
for i in test_list: 
      
    # using count() to get count of elements
    freq = test_list.count(i) 
      
    # checking if not already entered in results
    if freq > K and i not in res: 
        res.append(i)
  
# printing results 
print("The required elements : " + str(res))

Output

The original list : [4, 6, 4, 3, 3, 4, 3, 7, 8, 8]
The required elements : [4, 3]

Method #2 : Using list comprehension + Counter()

In this, we perform the task of counting using Counter() and the iteration part is done inside list comprehension.

Python3

# Python3 code to demonstrate working of 
# Extract elements with Frequency greater than K
# Using list comprehension + Counter()
from collections import Counter
  
# initializing list
test_list = [4, 6, 4, 3, 3, 4, 3, 7, 8, 8]
  
# printing string
print("The original list : " + str(test_list))
  
# initializing K 
K = 2
  
# using list comprehension to bind result
res = [ele for ele, cnt in Counter(test_list).items() if cnt > K]
  
# printing results 
print("The required elements : " + str(res))

Output

The original list : [4, 6, 4, 3, 3, 4, 3, 7, 8, 8]
The required elements : [4, 3]

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