Issue 2025: Add tuple.count() and tuple.index() to follow the ABC in collections.Sequence.

Lib/test/seq_tests.py

@@ -4,6 +4,7 @@ Tests common to tuple, list and UserList.UserList
 
 import unittest
 from test import test_support
+import sys
 
 # Various iterables
 # This is used for checking the constructor (here and in test_deque.py)
@@ -328,3 +329,64 @@ class CommonTest(unittest.TestCase):
         self.assertEqual(a.__getitem__(slice(3,5)), self.type2test([]))
         self.assertRaises(ValueError, a.__getitem__, slice(0, 10, 0))
         self.assertRaises(TypeError, a.__getitem__, 'x')
+
+    def test_count(self):
+        a = self.type2test([0, 1, 2])*3
+        self.assertEqual(a.count(0), 3)
+        self.assertEqual(a.count(1), 3)
+        self.assertEqual(a.count(3), 0)
+
+        self.assertRaises(TypeError, a.count)
+
+        class BadExc(Exception):
+            pass
+
+        class BadCmp:
+            def __eq__(self, other):
+                if other == 2:
+                    raise BadExc()
+                return False
+
+        self.assertRaises(BadExc, a.count, BadCmp())
+
+    def test_index(self):
+        u = self.type2test([0, 1])
+        self.assertEqual(u.index(0), 0)
+        self.assertEqual(u.index(1), 1)
+        self.assertRaises(ValueError, u.index, 2)
+
+        u = self.type2test([-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)
+
+        self.assertRaises(TypeError, u.index)
+
+        class BadExc(Exception):
+            pass
+
+        class BadCmp:
+            def __eq__(self, other):
+                if other == 2:
+                    raise BadExc()
+                return False
+
+        a = self.type2test([0, 1, 2, 3])
+        self.assertRaises(BadExc, a.index, BadCmp())
+
+        a = self.type2test([-2, -1, 0, 0, 1, 2])
+        self.assertEqual(a.index(0), 2)
+        self.assertEqual(a.index(0, 2), 2)
+        self.assertEqual(a.index(0, -4), 2)
+        self.assertEqual(a.index(-2, -10), 0)
+        self.assertEqual(a.index(0, 3), 3)
+        self.assertEqual(a.index(0, -3), 3)
+        self.assertEqual(a.index(0, 3, 4), 3)
+        self.assertEqual(a.index(0, -3, -2), 3)
+        self.assertEqual(a.index(0, -4*sys.maxint, 4*sys.maxint), 2)
+        self.assertRaises(ValueError, a.index, 0, 4*sys.maxint,-4*sys.maxint)
+        self.assertRaises(ValueError, a.index, 2, 0, -10)

Misc/NEWS

@@ -25,6 +25,9 @@ Core and builtins
 - Issue #1678380: Fix a bug that identifies 0j and -0j when they appear
   in the same code unit.
 
+- Issue #2025 :  Add tuple.count() and tuple.index() methods to comply with
+  the collections.Sequence API.
+
 - Patch #1970 by Antoine Pitrou: Speedup unicode whitespace and linebreak
   detection
 

Objects/tupleobject.c

@@ -455,6 +455,53 @@ tuplerepeat(PyTupleObject *a, Py_ssize_t n)
 	return (PyObject *) np;
 }
 
+static PyObject *
+tupleindex(PyTupleObject *self, PyObject *args)
+{
+	Py_ssize_t i, start=0, stop=Py_SIZE(self);
+	PyObject *v;
+
+	if (!PyArg_ParseTuple(args, "O|O&O&:index", &v,
+	                            _PyEval_SliceIndex, &start,
+	                            _PyEval_SliceIndex, &stop))
+		return NULL;
+	if (start < 0) {
+		start += Py_SIZE(self);
+		if (start < 0)
+			start = 0;
+	}
+	if (stop < 0) {
+		stop += Py_SIZE(self);
+		if (stop < 0)
+			stop = 0;
+	}
+	for (i = start; i < stop && i < Py_SIZE(self); i++) {
+		int cmp = PyObject_RichCompareBool(self->ob_item[i], v, Py_EQ);
+		if (cmp > 0)
+			return PyLong_FromSsize_t(i);
+		else if (cmp < 0)
+			return NULL;
+	}
+	PyErr_SetString(PyExc_ValueError, "tuple.index(x): x not in list");
+	return NULL;
+}
+
+static PyObject *
+tuplecount(PyTupleObject *self, PyObject *v)
+{
+	Py_ssize_t count = 0;
+	Py_ssize_t i;
+
+	for (i = 0; i < Py_SIZE(self); i++) {
+		int cmp = PyObject_RichCompareBool(self->ob_item[i], v, Py_EQ);
+		if (cmp > 0)
+			count++;
+		else if (cmp < 0)
+			return NULL;
+	}
+	return PyLong_FromSsize_t(count);
+}
+
 static int
 tupletraverse(PyTupleObject *o, visitproc visit, void *arg)
 {
@@ -661,8 +708,15 @@ tuple_getnewargs(PyTupleObject *v)
 	
 }
 
+PyDoc_STRVAR(index_doc,
+"T.index(value, [start, [stop]]) -> integer -- return first index of value");
+PyDoc_STRVAR(count_doc,
+"T.count(value) -> integer -- return number of occurrences of value");
+
 static PyMethodDef tuple_methods[] = {
 	{"__getnewargs__",	(PyCFunction)tuple_getnewargs,	METH_NOARGS},
+	{"index",	(PyCFunction)tupleindex,  METH_VARARGS, index_doc},
+	{"count",	(PyCFunction)tuplecount,  METH_O, count_doc},
 	{NULL,		NULL}		/* sentinel */
 };