Use the format() function with a '02x' format.
>>> format(255, '02x')
'ff'
>>> format(2, '02x')
'02'
The 02 part tells format() to use at least 2 digits and to use zeros to pad it to length, x means lower-case hexadecimal.
The Format Specification Mini Language also gives you X for uppercase hex output, and you can prefix the field width with # to include a 0x or 0X prefix (depending on wether you used x or X as the formatter). Just take into account that you need to adjust the field width to allow for those extra 2 characters:
>>> format(255, '02X')
'FF'
>>> format(255, '#04x')
'0xff'
>>> format(255, '#04X')
'0XFF'
Another solution is:
>>> "".join(list(hex(255))[2:])
'ff'
Probably an archaic answer, but functional.
I think this is what you want:
>>> def twoDigitHex( number ):
... return '%02x' % number
...
>>> twoDigitHex( 2 )
'02'
>>> twoDigitHex( 255 )
'ff'
Source: Stackoverflow.com