Python – Filter rows with Elements as Multiple of K

Given a Matrix, extract rows with elements multiple of K.

Input : test_list = [[5, 10, 15], [4, 8, 12], [100, 15], [5, 10, 23]], K = 4 
Output : [[4, 8, 12]] 
Explanation : All are multiples of 4.

Input : test_list = [[5, 10, 15], [4, 8, 11], [100, 15], [5, 10, 23]], K = 4 
Output : [] 
Explanation : No rows with all multiples of 4. 

Method #1 : Using list comprehension + all()

In this, we check for all elements to be multiple using all(), and iteration of rows occur using list comprehension.

Python3

# Python3 code to demonstrate working of
# Access element at Kth index in String
# Using list comprehension + all()

# initializing string list
test_list = [[5, 10, 15], [4, 8, 3], [100, 15], [5, 10, 23]]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 5

res = [sub for sub in test_list if all(ele % K == 0 for ele in sub)]

# printing result
print("Rows with K multiples : " + str(res))

Output

The original list is : [[5, 10, 15], [4, 8, 3], [100, 15], [5, 10, 23]]
Rows with K multiples : [[5, 10, 15], [100, 15]]

Method #2 : Using filter() + lambda + all()

In this, we perform task of filtering using filter() and lambda function and task of checking for all elements in rows using all().

Python3

# Python3 code to demonstrate working of
# Access element at Kth index in String
# Using filter() + lambda + all()

# initializing string list
test_list = [[5, 10, 15], [4, 8, 3], [100, 15], [5, 10, 23]]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 5

# using all() to check for all elements being multiples of K
res = list(filter(lambda sub : all(ele % K == 0 for ele in sub), test_list))

# printing result
print("Rows with K multiples : " + str(res))

Output

The original list is : [[5, 10, 15], [4, 8, 3], [100, 15], [5, 10, 23]]
Rows with K multiples : [[5, 10, 15], [100, 15]]