From hexadecimal to one's complement in Python

bit-manipulation, ones-complement, python

Solution

Just use the XOR operator `^` against 0xFF:

>>> hex(0x9E ^ 0xFF)
'0x61'

If you need to work with values larger than a byte, you could create the mask from the `int.bit_length()` method on your value:

>>> value = 0x9E
>>> mask = (1 << value.bit_length()) - 1
>>> hex(value ^ mask)
'0x61'
>>> value = 0x9E9E
>>> mask = (1 << value.bit_length()) - 1
>>> hex(value ^ mask)
'0x6161'

Problem

Is there an easy way to produce a one's complement in python? For instance, if you take the hex value `0x9E`, I need to convert it to `0x61`. I need to swap the binary 1's for 0's and 0's for 1's. It feels like this should be simple.

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