Convert hex string to int in Python

How do I convert a hex string to an int in Python?

I may have it as "0xffff" or just "ffff".

Solution 1:

Without the 0x prefix, you need to specify the base explicitly, otherwise there's no way to tell:

x = int("deadbeef", 16)

With the 0x prefix, Python can distinguish hex and decimal automatically.

>>> print(int("0xdeadbeef", 0))
3735928559
>>> print(int("10", 0))
10

(You must specify 0 as the base in order to invoke this prefix-guessing behavior; if you omit the second parameter int() will assume base-10.)

Solution 2:

int(hexstring, 16) does the trick, and works with and without the 0x prefix:

>>> int("a", 16)
10
>>> int("0xa", 16)
10