Get size of integer in Python

Question

How can I find out the number of Bytes a certain number takes up to store e.g. for \\x00 - \\xFF I\'m looking to get 1 (Byte), \\x100 - \\xffff would give me 2 (Bytes) and s

Answer 1

Unless you're dealing with an array.array or a numpy.array - the size always has object overhead. And since Python deals with BigInts naturally, it's really, really hard to tell...

>>> i = 5
>>> import sys
>>> sys.getsizeof(i)
24

So on a 64bit platform it requires 24 bytes to store what could be stored in 3 bits.

However, if you did,

>>> s = '\x05'
>>> sys.getsizeof(s)
38

So no, not really - you've got the memory-overhead of the definition of the object rather than raw storage...

If you then take:

>>> a = array.array('i', [3])
>>> a
array('i', [3])
>>> sys.getsizeof(a)
60L
>>> a = array.array('i', [3, 4, 5])
>>> sys.getsizeof(a)
68L

Then you get what would be called normal byte boundaries, etc.. etc... etc...

If you just want what "purely" should be stored - minus object overhead, then from 2.(6|7) you can use some_int.bit_length() (otherwise just bitshift it as other answers have shown) and then work from there