The hex() function converts a specified integer number into a hexadecimal string representation.

Use int(x, base) with 16 as base to convert the string x to an integer. Call hex(number) with the integer as number to convert it to hexadecimal.

hex_string = "0xAA"

"0x" also required

an_integer = int(hex_string, 16)

hex_value = hex(an_integer)

print(hex_value)

Output

0xaa

Try this:

hex_str = "0xAD4"
hex_int = int(hex_str, 16)
new_int = hex_int + 0x200
print hex(new_int)

If you don't like the 0x in the beginning, replace the last line with

print hex(new_int)[2:]

Your class.function expects an integer which can be represented either by a decimal or a hexadecimal literal, so that these two calls are completely equivalent:

class.function(0x77)
class.function(119)  # 0x77 == 119

Even print(0x77) will show 119 (because decimal is the default representation).

So, we should rather be talking about converting a string representation to integer. The string can be a hexadecimal representation, like '0x77', then parse it with the base parameter:

 >>> int('0x77', 16)
 119

or a decimal one, then parse it as int('119').

Still, storing integer whenever you deal with integers is better.

EDIT: as @gnibbler suggested, you can parse as int(x, 0), which handles both formats.

You can transform your string to an integer generator. Apply hexadecimal formatting for each element and intercalate with a separator:

>>> s = "Hello, World!"
>>> ":".join("{:02x}".format(ord(c)) for c in s)
'48:65:6c:6c:6f:2c:20:57:6f:72:6c:64:21

You are looking for the chr function.

You seem to be mixing decimal representations of integers and hex representations of integers, so it's not entirely clear what you need. Based on the description you gave, I think one of these snippets shows what you want.

>>> chr(0x65) == '\x65'
True


>>> hex(65)
'0x41'
>>> chr(65) == '\x41'
True

Note that this is quite different from a string containing an integer as hex. If that is what you want, use the hex builtin.