Understanding about data type python

Question

Today I've started learn about reverse engineering. I met struc.pack(), but I dont know what \x12 meaning.

from struct import pack
pack('>I', 0x1337)
'\x00\x00\x137'

So \x137 is equal to 0x1337 (hex) in big-edian?

Answer 1

'0x137' is not a single byte, its actually two different bytes - 0x13 and 0x37 (or the character '7') . The hexadecimal value for the ascii value of '7' is 0x37, hence you get 0x137. Example -

>>> hex(ord('7'))
'0x37'