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

Based on @DSM's answer, and to support negative integers and varying byte sizes, I've created the following improved snippet:

def to_bytes(num, size):
        x = num if num >= 0 else 256**size + num
        h = hex(x)[2:].rstrip("L")
        return binascii.unhexlify("0"*((2*size)-len(h))+h)

This will properly handle negative integers and let the user set the number of bytes