diff options
Diffstat (limited to 'Doc/c-api/sequence.rst')
| -rw-r--r-- | Doc/c-api/sequence.rst | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/Doc/c-api/sequence.rst b/Doc/c-api/sequence.rst index 81f8557..6d22f35 100644 --- a/Doc/c-api/sequence.rst +++ b/Doc/c-api/sequence.rst @@ -9,7 +9,10 @@ Sequence Protocol .. c:function:: int PySequence_Check(PyObject *o) Return ``1`` if the object provides sequence protocol, and ``0`` otherwise. - This function always succeeds. + Note that it returns ``1`` for Python classes with a :meth:`__getitem__` + method unless they are :class:`dict` subclasses since in general case it + is impossible to determine what the type of keys it supports. This + function always succeeds. .. c:function:: Py_ssize_t PySequence_Size(PyObject *o) @@ -119,18 +122,27 @@ Sequence Protocol .. index:: builtin: tuple - Return a tuple object with the same contents as the arbitrary sequence *o* or - *NULL* on failure. If *o* is a tuple, a new reference will be returned, + Return a tuple object with the same contents as the sequence or iterable *o*, + or *NULL* on failure. If *o* is a tuple, a new reference will be returned, otherwise a tuple will be constructed with the appropriate contents. This is equivalent to the Python expression ``tuple(o)``. .. c:function:: PyObject* PySequence_Fast(PyObject *o, const char *m) - Return the sequence *o* as a list, unless it is already a tuple or list, in + Return the sequence or iterable *o* as a list, unless it is already a tuple or list, in which case *o* is returned. Use :c:func:`PySequence_Fast_GET_ITEM` to access the members of the result. Returns *NULL* on failure. If the object is not - a sequence, raises :exc:`TypeError` with *m* as the message text. + a sequence or iterable, raises :exc:`TypeError` with *m* as the message text. + + +.. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o) + + Returns the length of *o*, assuming that *o* was returned by + :c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be + gotten by calling :c:func:`PySequence_Size` on *o*, but + :c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list + or tuple. .. c:function:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i) @@ -155,12 +167,3 @@ Sequence Protocol :c:func:`PySequence_GetItem` but without checking that :c:func:`PySequence_Check` on *o* is true and without adjustment for negative indices. - - -.. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o) - - Returns the length of *o*, assuming that *o* was returned by - :c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be - gotten by calling :c:func:`PySequence_Size` on *o*, but - :c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list - or tuple. |