字典对象
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PyDictObject

   这个 "PyObject" 的子类型代表一个Python字典对象。

PyTypeObject PyDict_Type

   This instance of "PyTypeObject" represents the Python dictionary
   type.  This is exposed to Python programs as "dict" and
   "types.DictType".

int PyDict_Check(PyObject *p)

   如果 *p* 是字典对象或者字典类型的子类型的实例，则返回真。

   在 2.2 版更改: Allowed subtypes to be accepted.

int PyDict_CheckExact(PyObject *p)

   如果 *p* 是字典对象但不是字典类型的子类型的实例，则返回真。

   2.4 新版功能.

PyObject* PyDict_New()
    *Return value: New reference.*

   返回一个新的空字典或者返回 *NULL* 表示失败。

PyObject* PyDictProxy_New(PyObject *dict)
    *Return value: New reference.*

   Return a proxy object for a mapping which enforces read-only
   behavior. This is normally used to create a proxy to prevent
   modification of the dictionary for non-dynamic class types.

   2.2 新版功能.

void PyDict_Clear(PyObject *p)

   清空现有字典的所有键值对。

int PyDict_Contains(PyObject *p, PyObject *key)

   确定 *key* 是否包含在字典 *p* 中。如果 *key* 匹配上 *p* 的某一项，
   则返回 "1" ，否则返回 "0" 。返回 "-1" 表示出错。这等同于Python表达
   式 "key in p" 。

   2.4 新版功能.

PyObject* PyDict_Copy(PyObject *p)
    *Return value: New reference.*

   返回与 *p* 包含相同键值对的新词典。

   1.6 新版功能.

int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val)

   使用 *key* 作为键将 *value* 插入字典 *p* 。 *key* 必须为 *hashable*
   ；如果不是，会抛出 "TypeError" 异常。成功返回 "0" ，失败返回 "-1"
   。

int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val)

   Insert *value* into the dictionary *p* using *key* as a key. *key*
   should be a "char*".  The key object is created using
   "PyString_FromString(key)".  Return "0" on success or "-1" on
   failure.

int PyDict_DelItem(PyObject *p, PyObject *key)

   使用键 *key* 删除字典 *p* 中的条目。 *key* 必须是可哈希的；如果不是
   ，则抛出 "TypeError" 异常。成功时返回 "0" ，失败时返回 "-1" 。

int PyDict_DelItemString(PyObject *p, char *key)

   删除字典 *p* 中的条目，其中包含由字符串 *key* 指定的键。成功时返回
   “0，失败时返回“-1”。

PyObject* PyDict_GetItem(PyObject *p, PyObject *key)
    *Return value: Borrowed reference.*

   返回字典 *p* 中 *key* 作为键的对象。如果键 *key* 不存在则返回
   *NULL* ，但可以使用 *without* 设置例外。

PyObject* PyDict_GetItemString(PyObject *p, const char *key)
    *Return value: Borrowed reference.*

   This is the same as "PyDict_GetItem()", but *key* is specified as a
   "char*", rather than a "PyObject*".

PyObject* PyDict_Items(PyObject *p)
    *Return value: New reference.*

   Return a "PyListObject" containing all the items from the
   dictionary, as in the dictionary method "dict.items()".

PyObject* PyDict_Keys(PyObject *p)
    *Return value: New reference.*

   Return a "PyListObject" containing all the keys from the
   dictionary, as in the dictionary method "dict.keys()".

PyObject* PyDict_Values(PyObject *p)
    *Return value: New reference.*

   Return a "PyListObject" containing all the values from the
   dictionary *p*, as in the dictionary method "dict.values()".

Py_ssize_t PyDict_Size(PyObject *p)

   Return the number of items in the dictionary.  This is equivalent
   to "len(p)" on a dictionary.

   在 2.5 版更改: This function returned an "int" type.  This might
   require changes in your code for properly supporting 64-bit
   systems.

int PyDict_Next(PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue)

   Iterate over all key-value pairs in the dictionary *p*.  The
   "Py_ssize_t" referred to by *ppos* must be initialized to "0" prior
   to the first call to this function to start the iteration; the
   function returns true for each pair in the dictionary, and false
   once all pairs have been reported.  The parameters *pkey* and
   *pvalue* should either point to "PyObject*" variables that will be
   filled in with each key and value, respectively, or may be *NULL*.
   Any references returned through them are borrowed.  *ppos* should
   not be altered during iteration. Its value represents offsets
   within the internal dictionary structure, and since the structure
   is sparse, the offsets are not consecutive.

   例如:

      PyObject *key, *value;
      Py_ssize_t pos = 0;

      while (PyDict_Next(self->dict, &pos, &key, &value)) {
          /* do something interesting with the values... */
          ...
      }

   The dictionary *p* should not be mutated during iteration.  It is
   safe (since Python 2.1) to modify the values of the keys as you
   iterate over the dictionary, but only so long as the set of keys
   does not change.  For example:

      PyObject *key, *value;
      Py_ssize_t pos = 0;

      while (PyDict_Next(self->dict, &pos, &key, &value)) {
          int i = PyInt_AS_LONG(value) + 1;
          PyObject *o = PyInt_FromLong(i);
          if (o == NULL)
              return -1;
          if (PyDict_SetItem(self->dict, key, o) < 0) {
              Py_DECREF(o);
              return -1;
          }
          Py_DECREF(o);
      }

   在 2.5 版更改: This function used an "int *" type for *ppos*. This
   might require changes in your code for properly supporting 64-bit
   systems.

int PyDict_Merge(PyObject *a, PyObject *b, int override)

   Iterate over mapping object *b* adding key-value pairs to
   dictionary *a*. *b* may be a dictionary, or any object supporting
   "PyMapping_Keys()" and "PyObject_GetItem()". If *override* is true,
   existing pairs in *a* will be replaced if a matching key is found
   in *b*, otherwise pairs will only be added if there is not a
   matching key in *a*. Return "0" on success or "-1" if an exception
   was raised.

   2.2 新版功能.

int PyDict_Update(PyObject *a, PyObject *b)

   This is the same as "PyDict_Merge(a, b, 1)" in C, and is similar to
   "a.update(b)" in Python except that "PyDict_Update()" doesn’t fall
   back to the iterating over a sequence of key value pairs if the
   second argument has no “keys” attribute.  Return "0" on success or
   "-1" if an exception was raised.

   2.2 新版功能.

int PyDict_MergeFromSeq2(PyObject *a, PyObject *seq2, int override)

   Update or merge into dictionary *a*, from the key-value pairs in
   *seq2*. *seq2* must be an iterable object producing iterable
   objects of length 2, viewed as key-value pairs.  In case of
   duplicate keys, the last wins if *override* is true, else the first
   wins. Return "0" on success or "-1" if an exception was raised.
   Equivalent Python (except for the return value):

      def PyDict_MergeFromSeq2(a, seq2, override):
          for key, value in seq2:
              if override or key not in a:
                  a[key] = value

   2.2 新版功能.
