Why is an int in a list and in an compact array the same size? (24bytes)

Question

I was just reading that a compactArray defined as "i" should yield an array that hold integers with 2 or 4 bytes, but executing this snippet i am still getting 24bytes, which is the same as i would use integer lists.

import array
import sys
lowLevelArray = array.array("i", [1,2,3])
print sys.getsizeof(lowLevelArray[0])
pythonList = [1,2,3]
print sys.getsizeof(pythonList[0])

Output:

24

24

Answer 1

Because once you retrieve the integer it has to be wrapped in a python object so you can work with it. Everything in python is an object, it has no concept of primitives (even though the underlying implementation uses them).

Answer 2

The array object is more space efficient; it's 4 bytes per int it holds, plus 56 bytes overhead:

>>> sys.getsizeof(array.array("i", [1,2,3])
68L
>>> sys.getsizeof(array.array("i", range(1000))
4056L

However, when you do

>>> sys.getsizeof(lowLevelArray[0])

it first evaluates lowLevelArray[0] , which of course returns a normal integer, and then shows the size used by that . Which is completely unrelated to the fact that you also have an array that happens to hold the same value.