1 .. highlightlang:: c

     2 

     3 .. _tupleobjects:

     4 

     5 Tuple 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 

    46 .. cfunction:: PyObject* PyTuple_Pack(Py_ssize_t n, ...)

    47 

    48    Return a new tuple object of size *n*, or *NULL* on failure. The tuple values

    49    are initialized to the subsequent *n* C arguments pointing to Python objects.

    50    ``PyTuple_Pack(2, a, b)`` is equivalent to ``Py_BuildValue("(OO)", a, b)``.

    51 

    52    .. versionadded:: 2.4

    53 

    54 

    55 .. cfunction:: Py_ssize_t PyTuple_Size(PyObject *p)

    56 

    57    Take a pointer to a tuple object, and return the size of that tuple.

    58 

    59 

    60 .. cfunction:: Py_ssize_t PyTuple_GET_SIZE(PyObject *p)

    61 

    62    Return the size of the tuple *p*, which must be non-*NULL* and point to a tuple;

    63    no error checking is performed.

    64 

    65 

    66 .. cfunction:: PyObject* PyTuple_GetItem(PyObject *p, Py_ssize_t pos)

    67 

    68    Return the object at position *pos* in the tuple pointed to by *p*.  If *pos* is

    69    out of bounds, return *NULL* and sets an :exc:`IndexError` exception.

    70 

    71 

    72 .. cfunction:: PyObject* PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos)

    73 

    74    Like :cfunc:`PyTuple_GetItem`, but does no checking of its arguments.

    75 

    76 

    77 .. cfunction:: PyObject* PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high)

    78 

    79    Take a slice of the tuple pointed to by *p* from *low* to *high* and return it

    80    as a new tuple.

    81 

    82 

    83 .. cfunction:: int PyTuple_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)

    84 

    85    Insert a reference to object *o* at position *pos* of the tuple pointed to by

    86    *p*. Return ``0`` on success.

    87 

    88    .. note::

    89 

    90       This function "steals" a reference to *o*.

    91 

    92 

    93 .. cfunction:: void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o)

    94 

    95    Like :cfunc:`PyTuple_SetItem`, but does no error checking, and should *only* be

    96    used to fill in brand new tuples.

    97 

    98    .. note::

    99 

   100       This function "steals" a reference to *o*.

   101 

   102 

   103 .. cfunction:: int _PyTuple_Resize(PyObject **p, Py_ssize_t newsize)

   104 

   105    Can be used to resize a tuple.  *newsize* will be the new length of the tuple.

   106    Because tuples are *supposed* to be immutable, this should only be used if there

   107    is only one reference to the object.  Do *not* use this if the tuple may already

   108    be known to some other part of the code.  The tuple will always grow or shrink

   109    at the end.  Think of this as destroying the old tuple and creating a new one,

   110    only more efficiently.  Returns ``0`` on success. Client code should never

   111    assume that the resulting value of ``*p`` will be the same as before calling

   112    this function. If the object referenced by ``*p`` is replaced, the original

   113    ``*p`` is destroyed.  On failure, returns ``-1`` and sets ``*p`` to *NULL*, and

   114    raises :exc:`MemoryError` or :exc:`SystemError`.

   115 

   116    .. versionchanged:: 2.2

   117       Removed unused third parameter, *last_is_sticky*.

   118 

   119 

   120 .. cfunction:: int PyTuple_ClearFreeList(void)

   121 

   122    Clear the free list. Return the total number of freed items.

   123 

   124    .. versionadded:: 2.6