Question

What is the best way to reverse the significant bits of an integer in python and then get the resulting integer out of it?

For example I have the numbers 1,2,5,15 and I want to reverse the bits like so:

original      reversed
1  - 0001  -  1000 - 8
2  - 0010  -  0100 - 4
5  - 0101  -  1010 - 10
15 - 1111  -  1111 - 15

Given that these numbers are 32 bit integers how should I do this in python? The part I am unsure about is how to move individual bits around in python and if there is anything funny about using a 32bit field as an integer after doing so.

PS This isn’t homework, I am just trying to program the solution to a logic puzzle.

Answer 1

reversed_ = sum(1<<(numbits-1-i) for i in range(numbits) if original>>i&1)