Question

I converted unsigned long from c++ to eight bytes and send over network(0 position is the least significant).
How to convert on python side this eight bytes to number ( unsigned long)?

Answer 1

Use the struct module:

import struct

struct.unpack('Q', data)

Do carefully study the module documentation; the format 'Q' means ‘unsigned long long’, which has a standard size of 8 bytes. You can add a flag to indicate byte-order and alignment behaviour. Without a flag native byte order is assumed, use < or > to signify little or big endian byte ordering for example.