Python – Extract Rear K digits from Numbers

Given an Integer list, extract rear K digits from it.

Input : test_list = [5645, 23567, 34543, 87652, 2342], K = 2 
Output : [45, 67, 43, 52, 42] 
Explanation : Last 2 digits extracted.

Input : test_list = [5645, 23567, 34543, 87652, 2342], K = 4 
Output : [5645, 3567, 4543, 7652, 2342] 
Explanation : Last 4 digits extracted. 

Method #1 : Using list comprehension + % operator

In this technique, we modulo each number with 10^K to get the desired last K digits of each number.

Python3

# Python3 code to demonstrate working of
# Extract Rear K digits from Numbers
# Using list comprehension + % operator

# initializing list
test_list = [5645, 23567, 34543, 87652, 2342]

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

# initializing K
K = 3

# Getting remainder for each element
res = [ele % (10 ** K) for ele in test_list]

# printing result
print("Rear K digits of elements ? : " + str(res))

Output

The original list is : [5645, 23567, 34543, 87652, 2342]
Rear K digits of elements ? : [645, 567, 543, 652, 342]

Method #2 : Using str() + slicing 

In this, we perform task of getting rear elements using list slicing, and str() is used to convert each element to string.

Python3

# Python3 code to demonstrate working of
# Extract Rear K digits from Numbers
# Using str() + slicing

# initializing list
test_list = [5645, 23567, 34543, 87652, 2342]

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

# initializing K
K = 3

# getting integer using int() after slicing string
res = [int(str(idx)[-K:]) for idx in test_list]

# printing result
print("Rear K digits of elements ? : " + str(res))

Output

The original list is : [5645, 23567, 34543, 87652, 2342]
Rear K digits of elements ? : [645, 567, 543, 652, 342]