How to get Python to make leap yr function similar to range (start, stop, step)?

Question

I am trying to create a function for leap year and then create a generator that will function like the range(start, stop, step) command. For some reason my code below is not printing whether the written year is a leap year or not. I keep getting False when I type in known leap years and I 'm not sure what I did wrong.

def is_leap(Y):
    leap=False
    
    if Y % 4 == 0:
        leap=True
    elif Y % 100 == 0:
        leap=False
    elif Y % 400 == 0:
        leap=True
    return Y % 400 == 0
    return Y % 4 == 0

print(is_leap(2004))

Answer 1

You need to return leap. You're setting the variable, but then ignoring it.

Also, your tests are in the wrong order. If the year is divisible by 100, it will also be divisible by 4, so the first if Y % 4 == 0: condition will be true. elif conditions are only tested if all the previous conditions were false, so it will never perform those tests.

You don't really need the leap variable. Just return in the if statements.

def is_leap(Y):
    if Y % 400 == 0:
        return True
    if Y % 100 == 0:
        return False
    if Y % 4 == 0:
        return True
    return False

In this case you don't need elif, since return prevents falling through to the next if.

You can also combine all the conditions:

def is_leap(Y):
    return Y % 400 == 0 or (Y % 4 == 0 and Y % 100 != 0):