python 类型大小

返回单位：字节

sys.getsizeof()

import sys
>>> sys.getsizeof('3')
38
>>> sys.getsizeof('32')
39
>>> sys.getsizeof('325')
40
>>> sys.getsizeof(325)
24
>>> sys.getsizeof(1)
24
>>> sys.getsizeof(10000003250)
24
>>> sys.getsizeof(1000000000000000)
24
>>> sys.getsizeof(1000000000000000090)
24
>>> sys.getsizeof(10000000000000000900)
36

可以看出字符串是比整形占用空间小的，且整形在一定范围内占用空间是一样的

对比

import timeit
import sys
def f():
    a, b, c = 3,2,1
    return sys.getsizeof(a * 100 + b * 10 + c)

def g():
    a, b, c = 3,2,1
    return sys.getsizeof(str(a) + str(b) + str(c))

def f2():
    a, b, c = 3,2,1
    return a * 100 + b * 10 + c

def g2():
    a, b, c = 3,2,1
    return str(a) + str(b) + str(c)

print min(timeit.repeat(f2))
print min(timeit.repeat(g2))
print f()
print g()

结果

0.296730041504
0.70504784584
24
40

可以看出f()无论是从速度还是从内存占用都完胜g()

字典

>>> a
{1: 'a', 2: 'b'}
>>> sys.getsizeof(a)
280
>>> a[4] = "askjdfjllllllllllllll"
>>> a[5] = "askjdfjllllllllllllll"
>>> a
{1: 'a', 2: 'b', 4: 'askjdfjllllllllllllll', 5: 'askjdfjllllllllllllll'}
>>> sys.getsizeof(a)
280
>>> sys.getsizeof(a[1])
38
>>> for i in range(100):
...     a[i] = "fq08888888888" * 20
... 
>>> len(a)
100
>>> sys.getsizeof(a)
12568