Issue #27506: Support bytes/bytearray.translate() delete as keyword argument

Patch by Xiang Zhang.

Doc/library/stdtypes.rst

@@ -2631,8 +2631,8 @@ arbitrary binary data.
    The prefix(es) to search for may be any :term:`bytes-like object`.
 
 
-.. method:: bytes.translate(table[, delete])
+.. method:: bytes.translate(table, delete=b'')
-            bytearray.translate(table[, delete])
+            bytearray.translate(table, delete=b'')
 
    Return a copy of the bytes or bytearray object where all bytes occurring in
    the optional argument *delete* are removed, and the remaining bytes have
@@ -2648,6 +2648,9 @@ arbitrary binary data.
       >>> b'read this short text'.translate(None, b'aeiou')
       b'rd ths shrt txt'
 
+   .. versionchanged:: 3.6
+      *delete* is now supported as a keyword argument.
+
 
 The following methods on bytes and bytearray objects have default behaviours
 that assume the use of ASCII compatible binary formats, but can still be used

Lib/test/test_bytes.py

@@ -689,6 +689,37 @@ class BaseBytesTest:
         test.support.check_free_after_iterating(self, iter, self.type2test)
         test.support.check_free_after_iterating(self, reversed, self.type2test)
 
+    def test_translate(self):
+        b = self.type2test(b'hello')
+        rosetta = bytearray(range(256))
+        rosetta[ord('o')] = ord('e')
+
+        self.assertRaises(TypeError, b.translate)
+        self.assertRaises(TypeError, b.translate, None, None)
+        self.assertRaises(ValueError, b.translate, bytes(range(255)))
+
+        c = b.translate(rosetta, b'hello')
+        self.assertEqual(b, b'hello')
+        self.assertIsInstance(c, self.type2test)
+
+        c = b.translate(rosetta)
+        d = b.translate(rosetta, b'')
+        self.assertEqual(c, d)
+        self.assertEqual(c, b'helle')
+
+        c = b.translate(rosetta, b'l')
+        self.assertEqual(c, b'hee')
+        c = b.translate(None, b'e')
+        self.assertEqual(c, b'hllo')
+
+        # test delete as a keyword argument
+        c = b.translate(rosetta, delete=b'')
+        self.assertEqual(c, b'helle')
+        c = b.translate(rosetta, delete=b'l')
+        self.assertEqual(c, b'hee')
+        c = b.translate(None, delete=b'e')
+        self.assertEqual(c, b'hllo')
+
 
 class BytesTest(BaseBytesTest, unittest.TestCase):
     type2test = bytes
@@ -1449,24 +1480,6 @@ class AssortedBytesTest(unittest.TestCase):
             self.assertRaises(SyntaxError, eval,
                               'b"%s"' % chr(c))
 
-    def test_translate(self):
-        b = b'hello'
-        ba = bytearray(b)
-        rosetta = bytearray(range(0, 256))
-        rosetta[ord('o')] = ord('e')
-        c = b.translate(rosetta, b'l')
-        self.assertEqual(b, b'hello')
-        self.assertEqual(c, b'hee')
-        c = ba.translate(rosetta, b'l')
-        self.assertEqual(ba, b'hello')
-        self.assertEqual(c, b'hee')
-        c = b.translate(None, b'e')
-        self.assertEqual(c, b'hllo')
-        c = ba.translate(None, b'e')
-        self.assertEqual(c, b'hllo')
-        self.assertRaises(TypeError, b.translate, None, None)
-        self.assertRaises(TypeError, ba.translate, None, None)
-
     def test_split_bytearray(self):
         self.assertEqual(b'a b'.split(memoryview(b' ')), [b'a', b'b'])
 

Misc/NEWS

@@ -10,6 +10,9 @@ What's New in Python 3.6.0 beta 1
 Core and Builtins
 -----------------
 
+- Issue #27506: Support passing the bytes/bytearray.translate() "delete"
+  argument by keyword.
+
 - Issue #27587: Fix another issue found by PVS-Studio: Null pointer check
   after use of 'def' in _PyState_AddModule().
   Initial patch by Christian Heimes.

Objects/bytearrayobject.c

@@ -1175,21 +1175,19 @@ bytearray.translate
 
     table: object
         Translation table, which must be a bytes object of length 256.
-    [
-    deletechars: object
-    ]
     /
+    delete as deletechars: object(c_default="NULL") = b''
 
 Return a copy with each character mapped by the given translation table.
 
-All characters occurring in the optional argument deletechars are removed.
+All characters occurring in the optional argument delete are removed.
 The remaining characters are mapped through the given translation table.
 [clinic start generated code]*/
 
 static PyObject *
 bytearray_translate_impl(PyByteArrayObject *self, PyObject *table,
-                         int group_right_1, PyObject *deletechars)
+                         PyObject *deletechars)
-/*[clinic end generated code: output=2bebc86a9a1ff083 input=846a01671bccc1c5]*/
+/*[clinic end generated code: output=b6a8f01c2a74e446 input=cfff956d4d127a9b]*/
 {
     char *input, *output;
     const char *table_chars;
@@ -1258,8 +1256,7 @@ bytearray_translate_impl(PyByteArrayObject *self, PyObject *table,
     for (i = inlen; --i >= 0; ) {
         c = Py_CHARMASK(*input++);
         if (trans_table[c] != -1)
-            if (Py_CHARMASK(*output++ = (char)trans_table[c]) == c)
+            *output++ = (char)trans_table[c];
-                    continue;
     }
     /* Fix the size of the resulting string */
     if (inlen > 0)

Objects/bytesobject.c

@@ -2045,21 +2045,19 @@ bytes.translate
 
     table: object
         Translation table, which must be a bytes object of length 256.
-    [
-    deletechars: object
-    ]
     /
+    delete as deletechars: object(c_default="NULL") = b''
 
 Return a copy with each character mapped by the given translation table.
 
-All characters occurring in the optional argument deletechars are removed.
+All characters occurring in the optional argument delete are removed.
 The remaining characters are mapped through the given translation table.
 [clinic start generated code]*/
 
 static PyObject *
-bytes_translate_impl(PyBytesObject *self, PyObject *table, int group_right_1,
+bytes_translate_impl(PyBytesObject *self, PyObject *table,
                      PyObject *deletechars)
-/*[clinic end generated code: output=233df850eb50bf8d input=ca20edf39d780d49]*/
+/*[clinic end generated code: output=43be3437f1956211 input=0ecdf159f654233c]*/
 {
     char *input, *output;
     Py_buffer table_view = {NULL, NULL};

Objects/clinic/bytearrayobject.c.h

@@ -39,47 +39,38 @@ bytearray_copy(PyByteArrayObject *self, PyObject *Py_UNUSED(ignored))
 }
 
 PyDoc_STRVAR(bytearray_translate__doc__,
-"translate(table, [deletechars])\n"
+"translate($self, table, /, delete=b\'\')\n"
+"--\n"
+"\n"
 "Return a copy with each character mapped by the given translation table.\n"
 "\n"
 "  table\n"
 "    Translation table, which must be a bytes object of length 256.\n"
 "\n"
-"All characters occurring in the optional argument deletechars are removed.\n"
+"All characters occurring in the optional argument delete are removed.\n"
 "The remaining characters are mapped through the given translation table.");
 
 #define BYTEARRAY_TRANSLATE_METHODDEF    \
-    {"translate", (PyCFunction)bytearray_translate, METH_VARARGS, bytearray_translate__doc__},
+    {"translate", (PyCFunction)bytearray_translate, METH_VARARGS|METH_KEYWORDS, bytearray_translate__doc__},
 
 static PyObject *
 bytearray_translate_impl(PyByteArrayObject *self, PyObject *table,
-                         int group_right_1, PyObject *deletechars);
+                         PyObject *deletechars);
 
 static PyObject *
-bytearray_translate(PyByteArrayObject *self, PyObject *args)
+bytearray_translate(PyByteArrayObject *self, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "delete", NULL};
+    static _PyArg_Parser _parser = {"O|O:translate", _keywords, 0};
     PyObject *table;
-    int group_right_1 = 0;
     PyObject *deletechars = NULL;
 
-    switch (PyTuple_GET_SIZE(args)) {
+    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        case 1:
+        &table, &deletechars)) {
-            if (!PyArg_ParseTuple(args, "O:translate", &table)) {
         goto exit;
     }
-            break;
+    return_value = bytearray_translate_impl(self, table, deletechars);
-        case 2:
-            if (!PyArg_ParseTuple(args, "OO:translate", &table, &deletechars)) {
-                goto exit;
-            }
-            group_right_1 = 1;
-            break;
-        default:
-            PyErr_SetString(PyExc_TypeError, "bytearray.translate requires 1 to 2 arguments");
-            goto exit;
-    }
-    return_value = bytearray_translate_impl(self, table, group_right_1, deletechars);
 
 exit:
     return return_value;
@@ -720,4 +711,4 @@ bytearray_sizeof(PyByteArrayObject *self, PyObject *Py_UNUSED(ignored))
 {
     return bytearray_sizeof_impl(self);
 }
-/*[clinic end generated code: output=0af30f8c0b1ecd76 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=59a0c86b29ff06d1 input=a9049054013a1b77]*/

Objects/clinic/bytesobject.c.h

@@ -269,47 +269,38 @@ exit:
 }
 
 PyDoc_STRVAR(bytes_translate__doc__,
-"translate(table, [deletechars])\n"
+"translate($self, table, /, delete=b\'\')\n"
+"--\n"
+"\n"
 "Return a copy with each character mapped by the given translation table.\n"
 "\n"
 "  table\n"
 "    Translation table, which must be a bytes object of length 256.\n"
 "\n"
-"All characters occurring in the optional argument deletechars are removed.\n"
+"All characters occurring in the optional argument delete are removed.\n"
 "The remaining characters are mapped through the given translation table.");
 
 #define BYTES_TRANSLATE_METHODDEF    \
-    {"translate", (PyCFunction)bytes_translate, METH_VARARGS, bytes_translate__doc__},
+    {"translate", (PyCFunction)bytes_translate, METH_VARARGS|METH_KEYWORDS, bytes_translate__doc__},
 
 static PyObject *
-bytes_translate_impl(PyBytesObject *self, PyObject *table, int group_right_1,
+bytes_translate_impl(PyBytesObject *self, PyObject *table,
                      PyObject *deletechars);
 
 static PyObject *
-bytes_translate(PyBytesObject *self, PyObject *args)
+bytes_translate(PyBytesObject *self, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "delete", NULL};
+    static _PyArg_Parser _parser = {"O|O:translate", _keywords, 0};
     PyObject *table;
-    int group_right_1 = 0;
     PyObject *deletechars = NULL;
 
-    switch (PyTuple_GET_SIZE(args)) {
+    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        case 1:
+        &table, &deletechars)) {
-            if (!PyArg_ParseTuple(args, "O:translate", &table)) {
         goto exit;
     }
-            break;
+    return_value = bytes_translate_impl(self, table, deletechars);
-        case 2:
-            if (!PyArg_ParseTuple(args, "OO:translate", &table, &deletechars)) {
-                goto exit;
-            }
-            group_right_1 = 1;
-            break;
-        default:
-            PyErr_SetString(PyExc_TypeError, "bytes.translate requires 1 to 2 arguments");
-            goto exit;
-    }
-    return_value = bytes_translate_impl(self, table, group_right_1, deletechars);
 
 exit:
     return return_value;
@@ -508,4 +499,4 @@ bytes_fromhex(PyTypeObject *type, PyObject *arg)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=637c2c14610d3c8d input=a9049054013a1b77]*/
+/*[clinic end generated code: output=5618c05c24c1e617 input=a9049054013a1b77]*/