Is there anyway i can know how much bytes taken by particular variable in python. E.g; lets say i have
int = 12
print (type(int))
it will print
<class 'int'>
But i wanted to know how many bytes it has taken on memory? is it possible?
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9 Answers
You can find the functionality you are looking for here (in sys.getsizeof - Python 2.6 and up).
Also: don't shadow the int builtin!
import sys
myint = 12
print(sys.getsizeof(myint))
7 Comments
itsaboutcode
is it really giving the size of myint it is returning 14, as far as i know int take 4 bytes, i think its returning the size of whole object, can i just know the size of only "INT"
Tim Pietzcker
From the docs:
getsizeof calls the object’s __sizeof__ method and adds an additional garbage collector overhead if the object is managed by the garbage collector.
u0b34a0f6ae
itsaboutcode: Do you want to leave the Python realm? What question do you really want to answer? If you want 4 as the answer, then
def sizeof(o): return 4.
jcdyer
And int is an object. There is nothing smaller in the python realm that you can get the size of. If you want the raw machine int, you may have to drop down into C (or Java, or C#, depending on your python).
u0b34a0f6ae
If you want to store many of int or another C-like datatype, using a minimum of bytes, you can use the
array class from the array module. |
if you want to know size of int, you can use struct
>>> import struct
>>> struct.calcsize("i")
4
otherwise, as others already pointed out, use getsizeof (2.6). there is also a recipe you can try.
Comments
In Python >= 2.6 you can use sys.getsizeof.
Comments
Numpy offers infrastructure to control data size. Here are examples (py3):
import numpy as np
x = np.float32(0)
print(x.nbytes) # 4
a = np.zeros((15, 15), np.int64)
print(a.nbytes) # 15 * 15 * 8 = 1800
This is super helpful when trying to submit data to the graphics card with pyopengl, for example.
1 Comment
Compholio
This is especially useful if you want to find the underlying representation of a python type, for example:
x = float(0.0); print(np.array(x).nbytes);
on python command prompt, you can use size of function
$ import python
$ import ctypes
$ ctypes.sizeof(ctypes.c_int)
and read more on it from https://docs.python.org/2/library/ctypes.html
Comments
In Python 3 you can use sys.getsizeof().
import sys
myint = 12
print(sys.getsizeof(myint))
Comments
The best library for that is guppy:
import guppy
import inspect
def get_object_size(obj):
h = guppy.hpy()
callers_local_vars = inspect.currentframe().f_back.f_locals.items()
vname = "Constant"
for var_name, var_val in callers_local_vars:
if var_val == obj:
vname = str(var_name)
size = str("{0:.2f} GB".format(float(h.iso(obj).domisize) / (1024 * 1024)))
return str("{}: {}".format(vname, size))
Comments
The accepted answer sys.getsizeof is correct.
But looking at your comment about the accepted answer you might want the number of bits a number is occupying in binary. You can use bit_length
(16).bit_length() # '10000' in binary
>> 5
(4).bit_length() # '100' in binary
>> 3
