1 .. highlightlang:: c 2 3 .. _sequence: 4 5 Sequence Protocol 6 ================= 7 8 9 .. c:function:: int PySequence_Check(PyObject *o) 10 11 Return ``1`` if the object provides sequence protocol, and ``0`` otherwise. 12 This function always succeeds. 13 14 15 .. c:function:: Py_ssize_t PySequence_Size(PyObject *o) 16 Py_ssize_t PySequence_Length(PyObject *o) 17 18 .. index:: builtin: len 19 20 Returns the number of objects in sequence *o* on success, and ``-1`` on failure. 21 For objects that do not provide sequence protocol, this is equivalent to the 22 Python expression ``len(o)``. 23 24 25 .. c:function:: PyObject* PySequence_Concat(PyObject *o1, PyObject *o2) 26 27 Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. 28 This is the equivalent of the Python expression ``o1 + o2``. 29 30 31 .. c:function:: PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count) 32 33 Return the result of repeating sequence object *o* *count* times, or *NULL* on 34 failure. This is the equivalent of the Python expression ``o * count``. 35 36 37 .. c:function:: PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2) 38 39 Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. 40 The operation is done *in-place* when *o1* supports it. This is the equivalent 41 of the Python expression ``o1 += o2``. 42 43 44 .. c:function:: PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count) 45 46 Return the result of repeating sequence object *o* *count* times, or *NULL* on 47 failure. The operation is done *in-place* when *o* supports it. This is the 48 equivalent of the Python expression ``o *= count``. 49 50 51 .. c:function:: PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i) 52 53 Return the *i*\ th element of *o*, or *NULL* on failure. This is the equivalent of 54 the Python expression ``o[i]``. 55 56 57 .. c:function:: PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) 58 59 Return the slice of sequence object *o* between *i1* and *i2*, or *NULL* on 60 failure. This is the equivalent of the Python expression ``o[i1:i2]``. 61 62 63 .. c:function:: int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v) 64 65 Assign object *v* to the *i*\ th element of *o*. Raise an exception 66 and return ``-1`` on failure; return ``0`` on success. This 67 is the equivalent of the Python statement ``o[i] = v``. This function *does 68 not* steal a reference to *v*. 69 70 If *v* is *NULL*, the element is deleted, however this feature is 71 deprecated in favour of using :c:func:`PySequence_DelItem`. 72 73 74 .. c:function:: int PySequence_DelItem(PyObject *o, Py_ssize_t i) 75 76 Delete the *i*\ th element of object *o*. Returns ``-1`` on failure. This is the 77 equivalent of the Python statement ``del o[i]``. 78 79 80 .. c:function:: int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v) 81 82 Assign the sequence object *v* to the slice in sequence object *o* from *i1* to 83 *i2*. This is the equivalent of the Python statement ``o[i1:i2] = v``. 84 85 86 .. c:function:: int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) 87 88 Delete the slice in sequence object *o* from *i1* to *i2*. Returns ``-1`` on 89 failure. This is the equivalent of the Python statement ``del o[i1:i2]``. 90 91 92 .. c:function:: Py_ssize_t PySequence_Count(PyObject *o, PyObject *value) 93 94 Return the number of occurrences of *value* in *o*, that is, return the number 95 of keys for which ``o[key] == value``. On failure, return ``-1``. This is 96 equivalent to the Python expression ``o.count(value)``. 97 98 99 .. c:function:: int PySequence_Contains(PyObject *o, PyObject *value) 100 101 Determine if *o* contains *value*. If an item in *o* is equal to *value*, 102 return ``1``, otherwise return ``0``. On error, return ``-1``. This is 103 equivalent to the Python expression ``value in o``. 104 105 106 .. c:function:: Py_ssize_t PySequence_Index(PyObject *o, PyObject *value) 107 108 Return the first index *i* for which ``o[i] == value``. On error, return 109 ``-1``. This is equivalent to the Python expression ``o.index(value)``. 110 111 112 .. c:function:: PyObject* PySequence_List(PyObject *o) 113 114 Return a list object with the same contents as the sequence or iterable *o*, 115 or *NULL* on failure. The returned list is guaranteed to be new. This is 116 equivalent to the Python expression ``list(o)``. 117 118 119 .. c:function:: PyObject* PySequence_Tuple(PyObject *o) 120 121 .. index:: builtin: tuple 122 123 Return a tuple object with the same contents as the arbitrary sequence *o* or 124 *NULL* on failure. If *o* is a tuple, a new reference will be returned, 125 otherwise a tuple will be constructed with the appropriate contents. This is 126 equivalent to the Python expression ``tuple(o)``. 127 128 129 .. c:function:: PyObject* PySequence_Fast(PyObject *o, const char *m) 130 131 Return the sequence *o* as a list, unless it is already a tuple or list, in 132 which case *o* is returned. Use :c:func:`PySequence_Fast_GET_ITEM` to access 133 the members of the result. Returns *NULL* on failure. If the object is not 134 a sequence, raises :exc:`TypeError` with *m* as the message text. 135 136 137 .. c:function:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i) 138 139 Return the *i*\ th element of *o*, assuming that *o* was returned by 140 :c:func:`PySequence_Fast`, *o* is not *NULL*, and that *i* is within bounds. 141 142 143 .. c:function:: PyObject** PySequence_Fast_ITEMS(PyObject *o) 144 145 Return the underlying array of PyObject pointers. Assumes that *o* was returned 146 by :c:func:`PySequence_Fast` and *o* is not *NULL*. 147 148 Note, if a list gets resized, the reallocation may relocate the items array. 149 So, only use the underlying array pointer in contexts where the sequence 150 cannot change. 151 152 153 .. c:function:: PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i) 154 155 Return the *i*\ th element of *o* or *NULL* on failure. Macro form of 156 :c:func:`PySequence_GetItem` but without checking that 157 :c:func:`PySequence_Check` on *o* is true and without adjustment for negative 158 indices. 159 160 161 .. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o) 162 163 Returns the length of *o*, assuming that *o* was returned by 164 :c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be 165 gotten by calling :c:func:`PySequence_Size` on *o*, but 166 :c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list 167 or tuple. 168
