python intobject大小

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# 64位系统
#python3                                        python2

In [4]: sys.getsizeof(1)                       In [4]: sys.getsizeof(1)
Out[4]: 28                                     Out[4]: 24

In [6]: sys.getsizeof(0)                       In [6]: sys.getsizeof(0)
Out[6]: 24                                     Out[6]: 24

在python2 int对象为24个字节,

#define PyObject_HEAD                   \
    Py_ssize_t ob_refcnt;               \
    struct _typeobject *ob_type;

typedef struct {
    PyObject_HEAD
    long ob_ival;
} PyIntObject;

python3中已不区分int,long对象，而是将python2中的long对象改名为int对象

typedef unsigned short digit;
struct _longobject {
    PyObject_VAR_HEAD
    digit ob_digit[1];
};

python3中sys.getsizeof(0) == 24

 /*zero is represented by ob_size == 0.当int值为0时，ob_size=0，所以不会分配  
 ob_digit[1],所以大小为24Bytes.*/

Ref：python源码