Question

def sum10(a, b):
    if sum([a, b]) % 10 == 0: return True; return False

print sum10(7, 3)
print sum10(-13, -17)
print sum10(3, 8)

the result is:

True
True
None

not what I expected:

True
True
False

any idea?

Answer 1

Your code

def sum10(a, b):
    if sum([a, b]) % 10 == 0: return True; return False

is equivalent to

def sum10(a, b):
    if sum([a, b]) % 10 == 0: 
        return True; return False

so return False is never evaluated.

---

Some (of the probably endless) alternatives:

    if sum([a, b]) % 10 == 0: 
        return True
    return False

or

    return sum([a, b]) % 10 == 0

or

    return True if sum([a, b]) % 10 == 0 else False

or

    return False if (a+b) % 10 else True

or (the most readable IMHO)

    return not (a + b) % 10