/Doc/c-api/tuple.rst

  1.. highlightlang:: c
  2
  3.. _tupleobjects:
  4
  5Tuple Objects
  6-------------
  7
  8.. index:: object: tuple
  9
 10
 11.. ctype:: PyTupleObject
 12
 13   This subtype of :ctype:`PyObject` represents a Python tuple object.
 14
 15
 16.. cvar:: PyTypeObject PyTuple_Type
 17
 18   .. index:: single: TupleType (in module types)
 19
 20   This instance of :ctype:`PyTypeObject` represents the Python tuple type; it is
 21   the same object as ``tuple`` and ``types.TupleType`` in the Python layer..
 22
 23
 24.. cfunction:: int PyTuple_Check(PyObject *p)
 25
 26   Return true if *p* is a tuple object or an instance of a subtype of the tuple
 27   type.
 28
 29   .. versionchanged:: 2.2
 30      Allowed subtypes to be accepted.
 31
 32
 33.. cfunction:: int PyTuple_CheckExact(PyObject *p)
 34
 35   Return true if *p* is a tuple object, but not an instance of a subtype of the
 36   tuple type.
 37
 38   .. versionadded:: 2.2
 39
 40
 41.. cfunction:: PyObject* PyTuple_New(Py_ssize_t len)
 42
 43   Return a new tuple object of size *len*, or *NULL* on failure.
 44
 45   .. versionchanged:: 2.5
 46      This function used an :ctype:`int` type for *len*. This might require
 47      changes in your code for properly supporting 64-bit systems.
 48
 49
 50.. cfunction:: PyObject* PyTuple_Pack(Py_ssize_t n, ...)
 51
 52   Return a new tuple object of size *n*, or *NULL* on failure. The tuple values
 53   are initialized to the subsequent *n* C arguments pointing to Python objects.
 54   ``PyTuple_Pack(2, a, b)`` is equivalent to ``Py_BuildValue("(OO)", a, b)``.
 55
 56   .. versionadded:: 2.4
 57
 58   .. versionchanged:: 2.5
 59      This function used an :ctype:`int` type for *n*. This might require
 60      changes in your code for properly supporting 64-bit systems.
 61
 62
 63.. cfunction:: Py_ssize_t PyTuple_Size(PyObject *p)
 64
 65   Take a pointer to a tuple object, and return the size of that tuple.
 66
 67   .. versionchanged:: 2.5
 68      This function returned an :ctype:`int` type. This might require changes
 69      in your code for properly supporting 64-bit systems.
 70
 71
 72.. cfunction:: Py_ssize_t PyTuple_GET_SIZE(PyObject *p)
 73
 74   Return the size of the tuple *p*, which must be non-*NULL* and point to a tuple;
 75   no error checking is performed.
 76
 77   .. versionchanged:: 2.5
 78      This function returned an :ctype:`int` type. This might require changes
 79      in your code for properly supporting 64-bit systems.
 80
 81
 82.. cfunction:: PyObject* PyTuple_GetItem(PyObject *p, Py_ssize_t pos)
 83
 84   Return the object at position *pos* in the tuple pointed to by *p*.  If *pos* is
 85   out of bounds, return *NULL* and sets an :exc:`IndexError` exception.
 86
 87   .. versionchanged:: 2.5
 88      This function used an :ctype:`int` type for *pos*. This might require
 89      changes in your code for properly supporting 64-bit systems.
 90
 91
 92.. cfunction:: PyObject* PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos)
 93
 94   Like :cfunc:`PyTuple_GetItem`, but does no checking of its arguments.
 95
 96   .. versionchanged:: 2.5
 97      This function used an :ctype:`int` type for *pos*. This might require
 98      changes in your code for properly supporting 64-bit systems.
 99
100
101.. cfunction:: PyObject* PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high)
102
103   Take a slice of the tuple pointed to by *p* from *low* to *high* and return it
104   as a new tuple.
105
106   .. versionchanged:: 2.5
107      This function used an :ctype:`int` type for *low* and *high*. This might
108      require changes in your code for properly supporting 64-bit systems.
109
110
111.. cfunction:: int PyTuple_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)
112
113   Insert a reference to object *o* at position *pos* of the tuple pointed to by
114   *p*. Return ``0`` on success.
115
116   .. note::
117
118      This function "steals" a reference to *o*.
119
120   .. versionchanged:: 2.5
121      This function used an :ctype:`int` type for *pos*. This might require
122      changes in your code for properly supporting 64-bit systems.
123
124
125.. cfunction:: void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o)
126
127   Like :cfunc:`PyTuple_SetItem`, but does no error checking, and should *only* be
128   used to fill in brand new tuples.
129
130   .. note::
131
132      This function "steals" a reference to *o*.
133
134   .. versionchanged:: 2.5
135      This function used an :ctype:`int` type for *pos*. This might require
136      changes in your code for properly supporting 64-bit systems.
137
138
139.. cfunction:: int _PyTuple_Resize(PyObject **p, Py_ssize_t newsize)
140
141   Can be used to resize a tuple.  *newsize* will be the new length of the tuple.
142   Because tuples are *supposed* to be immutable, this should only be used if there
143   is only one reference to the object.  Do *not* use this if the tuple may already
144   be known to some other part of the code.  The tuple will always grow or shrink
145   at the end.  Think of this as destroying the old tuple and creating a new one,
146   only more efficiently.  Returns ``0`` on success. Client code should never
147   assume that the resulting value of ``*p`` will be the same as before calling
148   this function. If the object referenced by ``*p`` is replaced, the original
149   ``*p`` is destroyed.  On failure, returns ``-1`` and sets ``*p`` to *NULL*, and
150   raises :exc:`MemoryError` or :exc:`SystemError`.
151
152   .. versionchanged:: 2.2
153      Removed unused third parameter, *last_is_sticky*.
154
155   .. versionchanged:: 2.5
156      This function used an :ctype:`int` type for *newsize*. This might
157      require changes in your code for properly supporting 64-bit systems.
158
159
160.. cfunction:: int PyTuple_ClearFreeList(void)
161
162   Clear the free list. Return the total number of freed items.
163
164   .. versionadded:: 2.6