Leap Year Function (Python)

Question

I know I’m missing something very simple, but I cannot for the life of me figure it out.
Here’s what I have right now.

def days_in_feb(user_year):
    if user_year % 100 == 0:
        if user_year % 400 == 0:
            user_year = print(f'{user_year} has 29 days in February.')
        else:
            user_year = print(f'{user_year} has 28 days in February.')
    else:
        if user_year % 4 == 0:
            user_year = print(f'{user_year} has 29 days in February.')
        else:
            user_year = print(f'{user_year} has 28 days in February.')
    return user_year
    
if __name__ == '__main__':
    user_year = int(input())
    print(f'{days_in_feb(user_year)}')

It will run fine once but then when it goes to take the next input, I get "days_in_feb() did not return a value. Your function may be missing a return statement." I think it has something to do with reassigning user_year to those print statements
in the function but without them I don’t know what to return.

Asked By: Carson

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Source

Answer 1

Instead of having the function print out your statments about the selected year, have them return a value and print then this value.

It is also okay to use longer function names and explain what the function does.

For example:

def get_days_in_feb_for_year(user_year):
    if user_year % 100 == 0:
        if user_year % 400 == 0:
            return f'{user_year} has 29 days in February.'
        else:
            return f'{user_year} has 28 days in February.'
    else:
        if user_year % 4 == 0:
            return f'{user_year} has 29 days in February.'
        else:
            return f'{user_year} has 28 days in February.'


if __name__ == '__main__':
    user_year = int(input())
    print(f'{get_days_in_feb_for_year(user_year)}')

Answered By: Ovski

Answer 2

Maybe of topic, but return what you really want from the function instead of creating side effect of printing from the function.

def days_in_feb(user_year):
    if user_year % 100 == 0:
        if user_year % 400 == 0:
            return 29
        else:
            return 28
    else:
        if user_year % 4 == 0:
            return 29
        else:
            return 28
    
if __name__ == '__main__':
    user_year = int(input())
    print(f'{user_year} has {days_in_feb(user_year)} days in Feburary.')

Answered By: Kapil Sinha

Leap Year Function (Python)

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