How to create a fixed size (unsigned) integer in python?

Question

I want to create a fixed size integer in python, for example 4 bytes. Coming from a C background, I expected that all the primitive types will occupy a constant space in mem

Answer 1

You can use struct.pack with the I modifier (unsigned int). This function will warn when the integer does not fit in four bytes:

>>> from struct import *
>>> pack('I', 1000)
'\xe8\x03\x00\x00'
>>> pack('I', 10000000)
'\x80\x96\x98\x00'
>>> pack('I', 1000000000000000)
sys:1: DeprecationWarning: 'I' format requires 0 <= number <= 4294967295
'\x00\x80\xc6\xa4'

You can also specify endianness.