Python – Elements with factors count less than K

Last Updated : 11 Oct, 2020

Given a List of elements, get all elements with factors less than K.

Examples:

Input : test_list = [60, 12, 100, 17, 18, 19]. K = 4
Output : [17, 19]
Explanation : Both elements have 2 factors.
Input : test_list = [60, 12, 100, 360, 18, 900]. K = 4
Output : []
Explanation : All have greater than 4 factors.

Method #1: Using list comprehension

In this, we use list comprehension to get factors count, and other list comprehension to iterate for all the elements in list.

Python3

# Python3 code to demonstrate working of
# Elements with factors less than K
# Using list comprehension
  
  
def factors_less_k(ele, K):
  
    # comparing for factors
    return len([idx for idx in range(1, ele + 1) if ele % idx == 0]) <= K
  
  
# initializing list
test_list = [60, 12, 100, 17, 18]
  
# printing original list
print("The original list is : " + str(test_list))
  
# initializing K
K = 4
  
# checking for each element
res = [ele for ele in test_list if factors_less_k(ele, K)]
  
# printing result
print("Filtered elements : " + str(res))

Output

The original list is : [60, 12, 100, 17, 18]
Filtered elements : [17]

Method #2 : Using filter() + lambda + len() + list comprehension

In this, task of filtering is done using filter() and lambda, len(), and list comprehension is used to perform tasks of getting factors.

Python3

# Python3 code to demonstrate working of
# Elements with factors less than K
# Using filter() + lambda + len() + list comprehension
  
  
def factors_less_k(ele, K):
  
    # comparing for factors
    return len([idx for idx in range(1, ele + 1) if ele % idx == 0]) <= K
  
  
# initializing list
test_list = [60, 12, 100, 17, 18]
  
# printing original list
print("The original list is : " + str(test_list))
  
# initializing K
K = 4
  
# filtering using filter() + lambda
res = list(filter(lambda ele: factors_less_k(ele, K), test_list))
  
# printing result
print("Filtered elements : " + str(res))

Output

The original list is : [60, 12, 100, 17, 18]
Filtered elements : [17]

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