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Minor improvements to itertools.tee():

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* tee object is no longer subclassable
* independent iterators renamed to "itertools.tee_iterator"
* fixed doc string typo and added entry in the module doc string
This commit is contained in:
Raymond Hettinger 2003-10-26 14:25:56 +00:00
parent 397b45d4ba
commit f0c5aec85f
2 changed files with 21 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

12
Lib/test/test_itertools.py
View file

@ -243,6 +243,18 @@ class TestBasicOps(unittest.TestCase):
self.assertRaises(TypeError, tee, 3) self.assertRaises(TypeError, tee, 3)
self.assertRaises(TypeError, tee, [1,2], 'x') self.assertRaises(TypeError, tee, [1,2], 'x')
try:
class A(tee): pass
except TypeError:
pass
else:
self.fail("tee constructor should not be subclassable")
# tee_iterator should not be instantiable
a, b = tee(xrange(10))
self.assertRaises(TypeError, type(a))
self.assert_(a is iter(a)) # tee_iterator should support __iter__
def test_StopIteration(self): def test_StopIteration(self):
self.assertRaises(StopIteration, izip().next) self.assertRaises(StopIteration, izip().next)

18
Modules/itertoolsmodule.c
View file

@ -113,12 +113,12 @@ ii_traverse(iiobject *ii, visitproc visit, void *arg)
return 0; return 0;
} }
PyDoc_STRVAR(ii_doc, "Independent iterators linked to a tee() object."); PyDoc_STRVAR(ii_doc, "Independent iterator created by tee(iterable).");
static PyTypeObject ii_type = { static PyTypeObject ii_type = {
PyObject_HEAD_INIT(&PyType_Type) PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */ 0, /* ob_size */
"itertools.independent_iterator", /* tp_name */ "itertools.tee_iterator", /* tp_name */
sizeof(iiobject), /* tp_basicsize */ sizeof(iiobject), /* tp_basicsize */
0, /* tp_itemsize */ 0, /* tp_itemsize */
/* methods */ /* methods */
@ -173,7 +173,7 @@ tee_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
outbasket = PyList_New(0); outbasket = PyList_New(0);
if (outbasket == NULL) goto fail; if (outbasket == NULL) goto fail;
to = (teeobject *)type->tp_alloc(type, 0); to = PyObject_GC_New(teeobject, &tee_type);
if (to == NULL) goto fail; if (to == NULL) goto fail;
to->it = it; to->it = it;
@ -181,6 +181,7 @@ tee_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
to->outbasket = outbasket; to->outbasket = outbasket;
to->save_mode = 1; to->save_mode = 1;
to->num_seen = 0; to->num_seen = 0;
PyObject_GC_Track(to);
/* create independent iterators */ /* create independent iterators */
result = PyTuple_New(2); result = PyTuple_New(2);
@ -212,7 +213,7 @@ tee_dealloc(teeobject *to)
Py_XDECREF(to->inbasket); Py_XDECREF(to->inbasket);
Py_XDECREF(to->outbasket); Py_XDECREF(to->outbasket);
Py_XDECREF(to->it); Py_XDECREF(to->it);
to->ob_type->tp_free(to); PyObject_GC_Del(to);
} }
static int static int
@ -241,7 +242,7 @@ tee_traverse(teeobject *to, visitproc visit, void *arg)
PyDoc_STRVAR(tee_doc, PyDoc_STRVAR(tee_doc,
"tee(iterable) --> (it1, it2)\n\ "tee(iterable) --> (it1, it2)\n\
\n\ \n\
Split the iterable into to independent iterables."); Split the iterable into two independent iterables.");
static PyTypeObject tee_type = { static PyTypeObject tee_type = {
PyObject_HEAD_INIT(NULL) PyObject_HEAD_INIT(NULL)
@ -262,11 +263,10 @@ static PyTypeObject tee_type = {
0, /* tp_hash */ 0, /* tp_hash */
0, /* tp_call */ 0, /* tp_call */
0, /* tp_str */ 0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */ 0, /* tp_getattro */
0, /* tp_setattro */ 0, /* tp_setattro */
0, /* tp_as_buffer */ 0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
Py_TPFLAGS_BASETYPE, /* tp_flags */
tee_doc, /* tp_doc */ tee_doc, /* tp_doc */
(traverseproc)tee_traverse, /* tp_traverse */ (traverseproc)tee_traverse, /* tp_traverse */
0, /* tp_clear */ 0, /* tp_clear */
@ -285,7 +285,6 @@ static PyTypeObject tee_type = {
0, /* tp_init */ 0, /* tp_init */
0, /* tp_alloc */ 0, /* tp_alloc */
tee_new, /* tp_new */ tee_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
}; };
/* cycle object **********************************************************/ /* cycle object **********************************************************/
@ -2092,6 +2091,7 @@ islice(seq, [start,] stop [, step]) --> elements from\n\
seq[start:stop:step]\n\ seq[start:stop:step]\n\
imap(fun, p, q, ...) --> fun(p0, q0), fun(p1, q1), ...\n\ imap(fun, p, q, ...) --> fun(p0, q0), fun(p1, q1), ...\n\
starmap(fun, seq) --> fun(*seq[0]), fun(*seq[1]), ...\n\ starmap(fun, seq) --> fun(*seq[0]), fun(*seq[1]), ...\n\
tee(it) --> (it1, it2) splits one iterator into two \n\
chain(p, q, ...) --> p0, p1, ... plast, q0, q1, ... \n\ chain(p, q, ...) --> p0, p1, ... plast, q0, q1, ... \n\
takewhile(pred, seq) --> seq[0], seq[1], until pred fails\n\ takewhile(pred, seq) --> seq[0], seq[1], until pred fails\n\
dropwhile(pred, seq) --> seq[n], seq[n+1], starting when pred fails\n\ dropwhile(pred, seq) --> seq[n], seq[n+1], starting when pred fails\n\