Multi-arg form for set.difference() and set.difference_update().
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 758ee7b..64d3c32 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -1583,10 +1583,13 @@
.. versionchanged:: 2.6
Accepts multiple input iterables.
- .. method:: difference(other)
- set - other
+ .. method:: difference(other, ...)
+ set - other - ...
- Return a new set with elements in the set that are not in *other*.
+ Return a new set with elements in the set that are not in the others.
+
+ .. versionchanged:: 2.6
+ Accepts multiple input iterables.
.. method:: symmetric_difference(other)
set ^ other
@@ -1650,10 +1653,13 @@
.. versionchanged:: 2.6
Accepts multiple input iterables.
- .. method:: difference_update(other)
- set -= other
+ .. method:: difference_update(other, ...)
+ set -= other | ...
- Update the set, removing elements found in *other*.
+ Update the set, removing elements found in others.
+
+ .. versionchanged:: 2.6
+ Accepts multiple input iterables.
.. method:: symmetric_difference_update(other)
set ^= other
diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
index b32d953..1b01954 100644
--- a/Lib/test/test_set.py
+++ b/Lib/test/test_set.py
@@ -149,6 +149,8 @@
self.assertEqual(self.thetype('abcba').difference(C('efgfe')), set('abc'))
self.assertEqual(self.thetype('abcba').difference(C('ccb')), set('a'))
self.assertEqual(self.thetype('abcba').difference(C('ef')), set('abc'))
+ self.assertEqual(self.thetype('abcba').difference(), set('abc'))
+ self.assertEqual(self.thetype('abcba').difference(C('a'), C('b')), set('c'))
def test_sub(self):
i = self.s.difference(self.otherword)
@@ -467,6 +469,18 @@
self.assertEqual(s.difference_update(C(p)), None)
self.assertEqual(s, set(q))
+ s = self.thetype('abcdefghih')
+ s.difference_update()
+ self.assertEqual(s, self.thetype('abcdefghih'))
+
+ s = self.thetype('abcdefghih')
+ s.difference_update(C('aba'))
+ self.assertEqual(s, self.thetype('cdefghih'))
+
+ s = self.thetype('abcdefghih')
+ s.difference_update(C('cdc'), C('aba'))
+ self.assertEqual(s, self.thetype('efghih'))
+
def test_isub(self):
self.s -= set(self.otherword)
for c in (self.word + self.otherword):
diff --git a/Misc/NEWS b/Misc/NEWS
index f721122..afaf05b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,7 +13,7 @@
-----------------
- Several set methods now accept multiple arguments: update(), union(),
- intersection() and intersection_update().
+ intersection(), intersection_update(), difference(), and difference_update().
- Issue #2898: Added sys.getsizeof() to retrieve size of objects in bytes.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 1127680..f3eea21 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1495,11 +1495,16 @@
}
static PyObject *
-set_difference_update(PySetObject *so, PyObject *other)
+set_difference_update(PySetObject *so, PyObject *args)
{
- if (set_difference_update_internal(so, other) != -1)
- Py_RETURN_NONE;
- return NULL;
+ Py_ssize_t i;
+
+ for (i=0 ; i<PyTuple_GET_SIZE(args) ; i++) {
+ PyObject *other = PyTuple_GET_ITEM(args, i);
+ if (set_difference_update_internal(so, other) == -1)
+ return NULL;
+ }
+ Py_RETURN_NONE;
}
PyDoc_STRVAR(difference_update_doc,
@@ -1557,10 +1562,34 @@
return result;
}
+static PyObject *
+set_difference_multi(PySetObject *so, PyObject *args)
+{
+ Py_ssize_t i;
+ PyObject *result, *other;
+
+ if (PyTuple_GET_SIZE(args) == 0)
+ return set_copy(so);
+
+ other = PyTuple_GET_ITEM(args, 0);
+ result = set_difference(so, other);
+ if (result == NULL)
+ return NULL;
+
+ for (i=1 ; i<PyTuple_GET_SIZE(args) ; i++) {
+ other = PyTuple_GET_ITEM(args, i);
+ if (set_difference_update_internal((PySetObject *)result, other) == -1) {
+ Py_DECREF(result);
+ return NULL;
+ }
+ }
+ return result;
+}
+
PyDoc_STRVAR(difference_doc,
-"Return the difference of two sets as a new set.\n\
+"Return the difference of two or more sets as a new set.\n\
\n\
-(i.e. all elements that are in this set but not the other.)");
+(i.e. all elements that are in this set but not the others.)");
static PyObject *
set_sub(PySetObject *so, PyObject *other)
{
@@ -1574,16 +1603,12 @@
static PyObject *
set_isub(PySetObject *so, PyObject *other)
{
- PyObject *result;
-
if (!PyAnySet_Check(other)) {
Py_INCREF(Py_NotImplemented);
return Py_NotImplemented;
}
- result = set_difference_update(so, other);
- if (result == NULL)
+ if (set_difference_update_internal(so, other) == -1)
return NULL;
- Py_DECREF(result);
Py_INCREF(so);
return (PyObject *)so;
}
@@ -1978,9 +2003,9 @@
copy_doc},
{"discard", (PyCFunction)set_discard, METH_O,
discard_doc},
- {"difference", (PyCFunction)set_difference, METH_O,
+ {"difference", (PyCFunction)set_difference_multi, METH_VARARGS,
difference_doc},
- {"difference_update", (PyCFunction)set_difference_update, METH_O,
+ {"difference_update", (PyCFunction)set_difference_update, METH_VARARGS,
difference_update_doc},
{"intersection",(PyCFunction)set_intersection_multi, METH_VARARGS,
intersection_doc},
@@ -2107,7 +2132,7 @@
contains_doc},
{"copy", (PyCFunction)frozenset_copy, METH_NOARGS,
copy_doc},
- {"difference", (PyCFunction)set_difference, METH_O,
+ {"difference", (PyCFunction)set_difference_multi, METH_VARARGS,
difference_doc},
{"intersection",(PyCFunction)set_intersection_multi, METH_VARARGS,
intersection_doc},