While loop with an integer condition?

def gcd(x, y):
       while(y): x, y = y, x % y
       return x

The function above returns the greatest common divisor of two numbers.
Why is y used as the condition in the while loop?

>Solution :

The expression in a while statement will be evaluated as a boolean. An integer of 0 will evaluate to False, everything else will evaluate to True.

Your statement is equivalent to while y != 0: