得到python對象的真實大小
sys.getsizeof只給你這個對象和他的屬性的大小，並沒有遞歸的尋找sub-attributes。
sys.getsizeof得到的大小總感覺奇怪…
下面是一個能到真實大小的腳本：
import sys
def get_size(obj, seen=None):
"""Recursively finds size of objects"""
size = sys.getsizeof(obj)
if seen is None:
seen = set()
obj_id = id(obj)
if obj_id in seen:
return 0
# Important mark as seen *before* entering recursion to gracefully handle
# self-referential objects
seen.add(obj_id)
if isinstance(obj, dict):
size += sum([get_size(v, seen) for v in obj.values()])
size += sum([get_size(k, seen) for k in obj.keys()])
elif hasattr(obj, '__dict__'):
size += get_size(obj.__dict__, seen)
elif hasattr(obj, '__iter__') and not isinstance(obj, (str, bytes, bytearray)):
size += sum([get_size(i, seen) for i in obj])
return size
例：
class People(object):
def __init__(self, name, age, dender):
self.name = name
self.age = age
self.gender = gender
p1 = People('Li Li', 30, 'Female')
p2 = People('Wang Wang', 25, 'Male')
>>>sys.getsizeof(p1)
>>>56
>>>sys.getsizeof(p2)
>>>56
>>>get_size(p1)
>>>465
>>>get_size(p2)
>>>467