.. highlightlang:: c .. _sequence: Sequence Protocol ================= .. c:function:: int PySequence_Check(PyObject *o) Return ``1`` if the object provides sequence protocol, and ``0`` otherwise. This function always succeeds. .. c:function:: Py_ssize_t PySequence_Size(PyObject *o) Py_ssize_t PySequence_Length(PyObject *o) .. index:: builtin: len Returns the number of objects in sequence *o* on success, and ``-1`` on failure. This is equivalent to the Python expression ``len(o)``. .. versionchanged:: 2.5 These functions returned an :c:type:`int` type. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject* PySequence_Concat(PyObject *o1, PyObject *o2) Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. This is the equivalent of the Python expression ``o1 + o2``. .. c:function:: PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count) Return the result of repeating sequence object *o* *count* times, or *NULL* on failure. This is the equivalent of the Python expression ``o * count``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *count*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2) Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. The operation is done *in-place* when *o1* supports it. This is the equivalent of the Python expression ``o1 += o2``. .. c:function:: PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count) Return the result of repeating sequence object *o* *count* times, or *NULL* on failure. The operation is done *in-place* when *o* supports it. This is the equivalent of the Python expression ``o *= count``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *count*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i) Return the *i*\ th element of *o*, or *NULL* on failure. This is the equivalent of the Python expression ``o[i]``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) Return the slice of sequence object *o* between *i1* and *i2*, or *NULL* on failure. This is the equivalent of the Python expression ``o[i1:i2]``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i1* and *i2*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v) Assign object *v* to the *i*\ th element of *o*. Raise an exception and return ``-1`` on failure; return ``0`` on success. This is the equivalent of the Python statement ``o[i] = v``. This function *does not* steal a reference to *v*. If *v* is *NULL*, the element is deleted, however this feature is deprecated in favour of using :c:func:`PySequence_DelItem`. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: int PySequence_DelItem(PyObject *o, Py_ssize_t i) Delete the *i*\ th element of object *o*. Returns ``-1`` on failure. This is the equivalent of the Python statement ``del o[i]``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v) Assign the sequence object *v* to the slice in sequence object *o* from *i1* to *i2*. Raise an exception and return ``-1`` on failure; return ``0`` on success. This is the equivalent of the Python statement ``o[i1:i2] = v``. If *v* is *NULL*, the slice is deleted, however this feature is deprecated in favour of using :c:func:`PySequence_DelSlice`. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i1* and *i2*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) Delete the slice in sequence object *o* from *i1* to *i2*. Returns ``-1`` on failure. This is the equivalent of the Python statement ``del o[i1:i2]``. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i1* and *i2*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: Py_ssize_t PySequence_Count(PyObject *o, PyObject *value) Return the number of occurrences of *value* in *o*, that is, return the number of keys for which ``o[key] == value``. On failure, return ``-1``. This is equivalent to the Python expression ``o.count(value)``. .. versionchanged:: 2.5 This function returned an :c:type:`int` type. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: int PySequence_Contains(PyObject *o, PyObject *value) Determine if *o* contains *value*. If an item in *o* is equal to *value*, return ``1``, otherwise return ``0``. On error, return ``-1``. This is equivalent to the Python expression ``value in o``. .. c:function:: Py_ssize_t PySequence_Index(PyObject *o, PyObject *value) Return the first index *i* for which ``o[i] == value``. On error, return ``-1``. This is equivalent to the Python expression ``o.index(value)``. .. versionchanged:: 2.5 This function returned an :c:type:`int` type. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject* PySequence_List(PyObject *o) Return a list object with the same contents as the arbitrary sequence *o*. The returned list is guaranteed to be new. .. c:function:: PyObject* PySequence_Tuple(PyObject *o) .. 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, 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 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. .. c:function:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i) Return the *i*\ th element of *o*, assuming that *o* was returned by :c:func:`PySequence_Fast`, *o* is not *NULL*, and that *i* is within bounds. .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i*. This might require changes in your code for properly supporting 64-bit systems. .. c:function:: PyObject** PySequence_Fast_ITEMS(PyObject *o) Return the underlying array of PyObject pointers. Assumes that *o* was returned by :c:func:`PySequence_Fast` and *o* is not *NULL*. Note, if a list gets resized, the reallocation may relocate the items array. So, only use the underlying array pointer in contexts where the sequence cannot change. .. versionadded:: 2.4 .. c:function:: PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i) Return the *i*\ th element of *o* or *NULL* on failure. Macro form of :c:func:`PySequence_GetItem` but without checking that :c:func:`PySequence_Check` on *o* is true and without adjustment for negative indices. .. versionadded:: 2.3 .. versionchanged:: 2.5 This function used an :c:type:`int` type for *i*. This might require changes in your code for properly supporting 64-bit systems. .. 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.