Swapping 1 with 0 and 0 with 1 in a Pythonic way

Question

In some part of my Python program I have a val variable that can be 1 or 0. If it's 1 I must change to 0, if it's 0 I must change to 1.

How do you do it in a Pythonic way?

if val == 1:     val = 0 elif val == 0:     val = 1 

it's too long!

I did:

swap = {0: 1, 1:0} 

So I can use it:

swap[val] 

Other ideas?

Answer 1

This isn't pythonic, but it is language neutral. Often val = 1 - val is simplest.

Answer 2

The shortest approach is using the bitwise operator XOR.

If you want val to be reassigned:

val ^= 1 

If you do not want val to be reassigned:

val ^ 1