Memory-usage of dictionary in Python?

Question

I am slightly confused when I use the getsizeof method in the sys module for dictionaries. Below I have created a simple dictionary of two strings.

Answer 1

The recursive getsizeof would get the actual size, but if you have multiple layers of dictionaries and only want to get a rough estimate. The json comes handy.

>>> first = 'abc'*1000
>>> second = 'def'*1000
>>> my_dictionary = {'first': first, 'second': second}
>>> getsizeof(first)
3049
>>> getsizeof(second)
3049
>>> getsizeof(my_dictionary)
288
>>> getsizeof(json.dumps(my_dictionary))
6076
>>> size = getsizeof(my_dictionary)
>>> size += sum(map(getsizeof, my_dictionary.values())) + sum(map(getsizeof, my_dictionary.keys()))
>>> size
6495