如何在Python中获得对象在内存中占用的大小?
当前回答
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
其他回答
我自己也遇到过很多次这个问题,我写了一个小函数(受到@aaron-hall的回答的启发)和测试,它完成了我所期望的sys。Getsizeof to do:
https://github.com/bosswissam/pysize
如果你对背景故事感兴趣,这就是
编辑:附上下面的代码以方便参考。要查看最新的代码,请检查github链接。
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
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
If you don't need the exact size of the object but roughly to know how big it is, one quick (and dirty) way is to let the program run, sleep for an extended period of time, and check the memory usage (ex: Mac's activity monitor) by this particular python process. This would be effective when you are trying to find the size of one single large object in a python process. For example, I recently wanted to check the memory usage of a new data structure and compare it with that of Python's set data structure. First I wrote the elements (words from a large public domain book) to a set, then checked the size of the process, and then did the same thing with the other data structure. I found out the Python process with a set is taking twice as much memory as the new data structure. Again, you wouldn't be able to exactly say the memory used by the process is equal to the size of the object. As the size of the object gets large, this becomes close as the memory consumed by the rest of the process becomes negligible compared to the size of the object you are trying to monitor.
Python 3.8(2019年第一季度)将改变sys. js的一些结果。getsizeof, Raymond Hettinger在此宣布:
Python容器在64位版本上要小8个字节。
tuple () 48 -> 40
list [] 64 ->56
set() 224 -> 216
dict {} 240 -> 232
这是在议题33597和稻田直树(甲烷)围绕紧凑型PyGC_Head和PR 7043的工作之后
这个想法将PyGC_Head大小减少到两个单词。 目前,PyGC_Head包含三个单词;Gc_prev, gc_next和gc_refcnt。 收集时使用Gc_refcnt,用于尝试删除。 Gc_prev用于跟踪和取消跟踪。 因此,如果我们可以在试删除时避免跟踪/取消跟踪,gc_prev和gc_refcnt可以共享相同的内存空间。
参见commit d5c875b:
从PyGC_Head中移除一个Py_ssize_t成员。 所有GC跟踪的对象(例如元组,列表,dict)大小减少4或8字节。
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
推荐文章
- 证书验证失败:无法获得本地颁发者证书
- 当使用pip3安装包时,“Python中的ssl模块不可用”
- 无法切换Python与pyenv
- Python if not == vs if !=
- 如何从scikit-learn决策树中提取决策规则?
- 为什么在Mac OS X v10.9 (Mavericks)的终端中apt-get功能不起作用?
- 将旋转的xtick标签与各自的xtick对齐
- 为什么元组可以包含可变项?
- 如何合并字典的字典?
- 如何创建类属性?
- 不区分大小写的“in”
- 在Python中获取迭代器中的元素个数
- 解析日期字符串并更改格式
- 使用try和。Python中的if
- 如何在Python中获得所有直接子目录