Getting around Python's referencing of variables

[Nevada]

I have a simple but very frustrating problem with Python. I know it should have a simple answer, but I'm just not familiar enough with Python to figure it out.

I need to do a 90 degree rotation of a velocity vector, but I'm having some trouble with the fact that Python, unlike C, treats assigned variables like pointers, rather than copies. My code is similar to this:

oldx = x
x = y
y = -oldx

The problem is that setting x = y also sets oldx = y, so I just get x = y and y = -y. Does anyone know how I can get a copy of a variable?

[martinsm]

Your code can be written like:
x,y = y,-x

But what type are x and y?
You can also take a look at copy (http://docs.python.org/lib/module-copy.html) module.

[Nevada]

Wow, I didn't even think of that. Thanks.