类型定义
INIT_TYPE(&PyDict_Type, "dict");
SETBUILTIN("dict", &PyDict_Type);
PyTypeObject PyDict_Type
的定义在 Objects/dictobject.c
中。
Include/cpython/dictobject.h
typedef struct {
PyObject_HEAD
/* Number of items in the dictionary */
Py_ssize_t ma_used;
/* Dictionary version: globally unique, value change each time
the dictionary is modified */
uint64_t ma_version_tag;
PyDictKeysObject *ma_keys;
/* If ma_values is NULL, the table is "combined": keys and values
are stored in ma_keys.
If ma_values is not NULL, the table is splitted:
keys are stored in ma_keys and values are stored in ma_values */
PyObject **ma_values;
} PyDictObject;
成员方法
setdefault
#define DICT_SETDEFAULT_METHODDEF \
{"setdefault", (PyCFunction)(void(*)(void))dict_setdefault, METH_FASTCALL, dict_setdefault__doc__},
static PyObject *
dict_setdefault(PyDictObject *self, PyObject *const *args, Py_ssize_t nargs)
{
PyObject *return_value = NULL;
PyObject *key;
PyObject *default_value = Py_None;
if (!_PyArg_CheckPositional("setdefault", nargs, 1, 2)) {
goto exit;
}
key = args[0];
if (nargs < 2) {
goto skip_optional;
}
default_value = args[1];
skip_optional:
return_value = dict_setdefault_impl(self, key, default_value);
exit:
return return_value;
}
static PyObject *
dict_setdefault_impl(PyDictObject *self, PyObject *key,
PyObject *default_value)
/*[clinic end generated code: output=f8c1101ebf69e220 input=0f063756e815fd9d]*/
{
PyObject *val;
val = PyDict_SetDefault((PyObject *)self, key, default_value);
Py_XINCREF(val);
return val;
}