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Python program to print perfect numbers from the given list of integers

Printing perfect numbers: Here, we are going to learn how to find and print the perfect numbers from a given list in Python? By Ankit Rai Last updated : January 04, 2024

A perfect number is a positive integer that is equal to the sum of its proper positive divisors.

Problem statement

Given a list of the integer numbers and we have to print all perfect numbers present in the given list.

Printing perfect numbers from a list

This program iterating through each number one by one in the list, and check whether a given number is a perfect number or not. If a perfect number is found then print it else skip it.

Here, the checkPerfectNum() function is used to find its all positive divisors excluding that number and sum it all and then check for perfect number condition.

Example

For Example, 28 is a perfect number since divisors of 28 are 1, 2, 4,7,14 then sum of its divisor is 1 + 2 + 4 + 7 + 14 = 28.

Python program to print perfect numbers from the given list of integers

# Define a function for checking perfect number
# and print that number
def checkPerfectNum(n):
    # initialisation
    i = 2
    sum = 1

    # iterating till n//2 value
    while i <= n // 2:
        # if proper divisor then add it.
        if n % i == 0:
            sum += i
        # incrementing i by one
        i += 1
        # check sum equal to n or not
        if sum == n:
            print(n, end=" ")

# Main code
# take list of number as an input from user
# and typecast into integer
print("Enter list of integers: ")
list_of_intgers = list(map(int, input().split()))

print("Given list of integers:", list_of_intgers)

print("Perfect numbers present in the list is: ")
# Iteration through the each element of
# the list one by one
for num in list_of_intgers:
    # function call
    checkPerfectNum(num)

Output

The output of the above example is:

Enter list of integers:
14 20 6 78 28
Given list of integers: [14, 20, 6, 78, 28]
Perfect numbers present in the list is:
6 28

To understand the above program, you should have the basic knowledge of the following Python topics:

• Python Variables
• Python Data Types
• Python print() Method
• Python input() Method
• Python int() Method
• Python Conditional Statements
• Python Loops

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