How to find the size of a Python object (list, dictionary) in bytes

Question

The len() function gives the length of the list or dictionary. I want to know the size of a python object, such as a list, dictionary, etc., in bytes. Is there any function for this?

Answer 1

You can use the getsizeof() function of the "sys" module. It returns the size of a python object in bytes. It works correctly for all built-in objects, but the returned size for the third-party extensions may not be correct.

Here is an example using the getsizeof() function:

>>> import random
>>> a=[random.randint(1,1000) for _ in range(1000)]
>>> len(a)
1000
>>> import sys
>>> sys.getsizeof(a)
9016

To find the total bytes consumed by the elements of a Numpy array, you can also use the nbytes attribute. However, it will not include the memory consumed by non-element attributes of the array object.

E.g.

>>> import numpy as np
>>> a=np.random.random(10241024)
>>> a.nbytes
81928192