How do I write a long integer as binary in Python?

Question

In Python, long integers have unlimited precision. I would like to write a 16 byte (128 bit) integer to a file. struct from the standard library supports only u

Answer 1

Why not use struct with the unsigned long long type twice?

import struct
some_file.write(struct.pack("QQ", var/(2**64), var%(2**64)))

That's documented here (scroll down to get the table with Q): http://docs.python.org/library/struct.html