如何在Python中获得对象在内存中占用的大小?


当前回答

如果性能不是问题,最简单的解决方案是pickle和测量:

import pickle

data = ...
len(pickle.dumps(data))

其他回答

如果不想包含链接(嵌套)对象的大小,请使用sys.getsizeof()。

然而,如果你想计算嵌套在列表、字典、集、元组中的子对象——通常这就是你要找的——使用如下所示的递归深层sizeof()函数:

import sys
def sizeof(obj):
    size = sys.getsizeof(obj)
    if isinstance(obj, dict): return size + sum(map(sizeof, obj.keys())) + sum(map(sizeof, obj.values()))
    if isinstance(obj, (list, tuple, set, frozenset)): return size + sum(map(sizeof, obj))
    return size

你也可以在漂亮的工具箱中找到这个函数,以及许多其他有用的一行程序:

https://github.com/mwojnars/nifty/blob/master/util.py

对于numpy数组,getsizeof不起作用-对我来说,它总是出于某种原因返回40:

from pylab import *
from sys import getsizeof
A = rand(10)
B = rand(10000)

然后(在ipython中):

In [64]: getsizeof(A)
Out[64]: 40

In [65]: getsizeof(B)
Out[65]: 40

不过令人高兴的是,:

In [66]: A.nbytes
Out[66]: 80

In [67]: B.nbytes
Out[67]: 80000

你可以序列化对象,以获得与对象大小密切相关的度量值:

import pickle

## let o be the object whose size you want to measure
size_estimate = len(pickle.dumps(o))

如果您想测量无法pickle的对象(例如,由于lambda表达式),dill或cloudpickle可以是一种解决方案。

用系统就行了。sys模块中定义的Getsizeof函数。

sys.getsizeof(object[, default]): Return the size of an object in bytes. The object can be any type of object. All built-in objects will return correct results, but this does not have to hold true for third-party extensions as it is implementation specific. Only the memory consumption directly attributed to the object is accounted for, not the memory consumption of objects it refers to. The default argument allows to define a value which will be returned if the object type does not provide means to retrieve the size and would cause a TypeError. getsizeof calls the object’s __sizeof__ method and adds an additional garbage collector overhead if the object is managed by the garbage collector. See recursive sizeof recipe for an example of using getsizeof() recursively to find the size of containers and all their contents.

python 3.0中的用法示例:

>>> import sys
>>> x = 2
>>> sys.getsizeof(x)
24
>>> sys.getsizeof(sys.getsizeof)
32
>>> sys.getsizeof('this')
38
>>> sys.getsizeof('this also')
48

如果你在python < 2.6并且没有sys. exe。Getsizeof可以使用这个扩展模块。但从来没用过。

下面是我根据之前对所有变量的列表大小的回答编写的一个快速脚本

for i in dir():
    print (i, sys.getsizeof(eval(i)) )