Question

Is it possible to make Python use less than 12 bytes for an int?

>>> x=int()
>>> x
0
>>> sys.getsizeof(x)
12

I am not a computer specialist but isn’t 12 bytes excessive?

The smallest int I want to store is 0, the largest int 147097614, so I shouldn’t really need more than 4 bytes.

(There is probably something I misunderstand here as I couldn’t find an answer anywhere on the net. Keep that in mind.)

Answer 1

In python, ints are objects just like everything else. Because of that, there is a little extra overhead just associated with the fact that you’re using an object which has some associated meta-data.

If you’re going to use lots of ints, and it makes sense to lay them out in an array-like structure, you should look into numpy. Numpy ndarray objects will have a little overhead associated with them for the various pieces of meta-data that the array objects keep track of, but the actual data is stored as the datatype you specify (e.g. numpy.int32 for a 4-byte integer.)

Thus, if you have:

import numpy as np
a = np.zeros(5000,dtype=np.int32)

The array will take only slightly more than 4*5000 = 20000 bytes of your memory