SF #754014: list.index() should accept optional start, end arguments

Also, modified UserList.index() to match and expanded the related tests.

Lib/UserList.py

@@ -75,7 +75,7 @@ class UserList:
     def pop(self, i=-1): return self.data.pop(i)
     def remove(self, item): self.data.remove(item)
     def count(self, item): return self.data.count(item)
-    def index(self, item): return self.data.index(item)
+    def index(self, item, *args): return self.data.index(item, *args)
     def reverse(self): self.data.reverse()
     def sort(self, *args): self.data.sort(*args)
     def extend(self, other):

Lib/test/test_types.py

@@ -366,7 +366,23 @@ b.insert(200, "right")
 if b != ["left",-2,-1,0,0,"foo",1,2,"right"]: raise TestFailed, 'list insert2'
 if a.count(0) != 2: raise TestFailed, ' list count'
 if a.index(0) != 2: raise TestFailed, 'list index'
+if a.index(0,2) != 2: raise TestFailed, 'list index, start argument'
+if a.index(-2,-10) != 0: raise TestFailed, 'list index, negative start argument'
+if a.index(0,3) != 3: raise TestFailed, 'list index, start argument'
+if a.index(0,3,4) != 3: raise TestFailed, 'list index, stop argument'
+try:
+    a.index(2,0,-10)
+except ValueError:
+    pass
+else:
+    raise TestFailed, 'list index, negative stop argument'
 a.remove(0)
+try:
+    a.index(2,0,4)
+except ValueError:
+    pass
+else:
+    raise TestFailed, 'list index, stop argument.'
 if a != [-2,-1,0,1,2]: raise TestFailed, 'list remove'
 a.reverse()
 if a != [2,1,0,-1,-2]: raise TestFailed, 'list reverse'

Lib/test/test_userlist.py

@@ -206,6 +206,15 @@ class UserListTest(unittest.TestCase):
         self.assertEqual(u.index(1), 1)
         self.assertRaises(ValueError, u.index, 2)
 
+        u = UserList([-2,-1,0,0,1,2])
+        self.assertEqual(u.count(0), 2)
+        self.assertEqual(u.index(0), 2)
+        self.assertEqual(u.index(0,2), 2)
+        self.assertEqual(u.index(-2,-10), 0)
+        self.assertEqual(u.index(0,3), 3)
+        self.assertEqual(u.index(0,3,4), 3)
+        self.assertRaises(ValueError, u.index, 2,0,-10)
+
     def test_reverse(self):
         u = UserList((0, 1))
         u2 = u[:]

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 2.3 beta 2?
 Core and builtins
 -----------------
 
+- list.index() now accepts optional start and stop arguments.  Similar
+  changes were made to UserList.index(). SF feature request 754014.
+
 - SF patch 751998 fixes an unwanted side effect of the previous fix
   for SF bug 742860 (the next item).
 

Objects/listobject.c

@@ -1827,11 +1827,16 @@ PyList_AsTuple(PyObject *v)
 }
 
 static PyObject *
-listindex(PyListObject *self, PyObject *v)
+listindex(PyListObject *self, PyObject *args)
 {
-	int i;
+	int i, start=0, stop=self->ob_size;
+	PyObject *v;
 
-	for (i = 0; i < self->ob_size; i++) {
+	if (!PyArg_ParseTuple(args, "O|ii:index", &v, &start, &stop))
+		return NULL;
+	start = max(0, start);
+	stop = max(0, min(self->ob_size, stop));
+	for (i = start; i < stop; i++) {
 		int cmp = PyObject_RichCompareBool(self->ob_item[i], v, Py_EQ);
 		if (cmp > 0)
 			return PyInt_FromLong((long)i);
@@ -2088,7 +2093,7 @@ PyDoc_STRVAR(pop_doc,
 PyDoc_STRVAR(remove_doc,
 "L.remove(value) -- remove first occurrence of value");
 PyDoc_STRVAR(index_doc,
-"L.index(value) -> integer -- return index of first occurrence of value");
+"L.index(value, [start, [stop]]) -> integer -- return first index of value");
 PyDoc_STRVAR(count_doc,
 "L.count(value) -> integer -- return number of occurrences of value");
 PyDoc_STRVAR(reverse_doc,
@@ -2102,7 +2107,7 @@ static PyMethodDef list_methods[] = {
 	{"extend",      (PyCFunction)listextend,  METH_O, extend_doc},
 	{"pop",		(PyCFunction)listpop, 	  METH_VARARGS, pop_doc},
 	{"remove",	(PyCFunction)listremove,  METH_O, remove_doc},
-	{"index",	(PyCFunction)listindex,   METH_O, index_doc},
+	{"index",	(PyCFunction)listindex,   METH_VARARGS, index_doc},
 	{"count",	(PyCFunction)listcount,   METH_O, count_doc},
 	{"reverse",	(PyCFunction)listreverse, METH_NOARGS, reverse_doc},
 	{"sort",	(PyCFunction)listsort, 	  METH_VARARGS, sort_doc},