Python assign sign of number to variable

Question

I have a variable of type int, it's Python, so it can be positive and negative. Now, I want to make another variable have the same sign as the first variable1. It's easy to do this by using an if statement and then assign -1 or +1 to a variable and multiply every variable I want to have this sign by the -1 or +1. But then I thought maybe there is another way to do this (e.g. a built-in function). Is there something like "sign = getsignbit(value)"?

edit: Solved! math.copysign did the thing, cmp(x,0) works too, but I don't only want -1, 0 or 1, but also turn a 5 into -5.

Answer 1

There's no built in sign function (see this answer for some explanation: Why doesn't Python have a sign function? ), but math.copysign might be useful to you. http://docs.python.org/2/library/math.html#math.copysign

Answer 2

I don't think there is a built-in function, but you can roll your own easily enough:

def the_sign(num):
    return cmp(num, 0)