diff options
| -rw-r--r-- | Doc/lib/libstdtypes.tex | 7 | ||||
| -rw-r--r-- | Doc/lib/libstring.tex | 3 | ||||
| -rw-r--r-- | Lib/string.py | 2 | ||||
| -rw-r--r-- | Lib/test/string_tests.py | 3 | ||||
| -rw-r--r-- | Misc/NEWS | 4 | ||||
| -rw-r--r-- | Objects/stringobject.c | 24 |
6 files changed, 33 insertions, 10 deletions
diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex index 0ad2ebc..c9fd272 100644 --- a/Doc/lib/libstdtypes.tex +++ b/Doc/lib/libstdtypes.tex @@ -878,6 +878,13 @@ must be a string of length 256. You can use the \function{maketrans()} helper function in the \refmodule{string} module to create a translation table. +For string objects, set the \var{table} argument to \code{None} +for translations that only delete characters: +\begin{verbatim} + >>> 'read this short text'.translate(None, 'aeiou') + 'rd ths shrt txt' +\end{verbatim} +\versionadded[Support for a \code{None} \var{table} argument]{2.6} For Unicode objects, the \method{translate()} method does not accept the optional \var{deletechars} argument. Instead, it diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex index bc1649f..055ac0c 100644 --- a/Doc/lib/libstring.tex +++ b/Doc/lib/libstring.tex @@ -419,7 +419,8 @@ parameter cannot be passed in earlier 2.2 versions]{2.2.3} Delete all characters from \var{s} that are in \var{deletechars} (if present), and then translate the characters using \var{table}, which must be a 256-character string giving the translation for each - character value, indexed by its ordinal. + character value, indexed by its ordinal. If \var{table} is \code{None}, + then only the character deletion step is performed. \end{funcdesc} \begin{funcdesc}{upper}{s} diff --git a/Lib/string.py b/Lib/string.py index 921bd8b..9e3cc41 100644 --- a/Lib/string.py +++ b/Lib/string.py @@ -487,7 +487,7 @@ def translate(s, table, deletions=""): deletions argument is not allowed for Unicode strings. """ - if deletions: + if deletions or table is None: return s.translate(table, deletions) else: # Add s[:0] so that if s is Unicode and table is an 8-bit string, diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py index 1aa68de..16161f3 100644 --- a/Lib/test/string_tests.py +++ b/Lib/test/string_tests.py @@ -1096,6 +1096,9 @@ class MixinStrStringUserStringTest: self.checkequal('Abc', 'abc', 'translate', table) self.checkequal('xyz', 'xyz', 'translate', table) self.checkequal('yz', 'xyz', 'translate', table, 'x') + self.checkequal('yx', 'zyzzx', 'translate', None, 'z') + self.checkequal('zyzzx', 'zyzzx', 'translate', None, '') + self.checkequal('zyzzx', 'zyzzx', 'translate', None) self.checkraises(ValueError, 'xyz', 'translate', 'too short', 'strip') self.checkraises(ValueError, 'xyz', 'translate', 'too short') @@ -14,6 +14,10 @@ Core and builtins - Request #1191699: Slices can now be pickled. +- Request #1193128: str.translate() now allows a None argument for + translations that only remove characters without re-mapping the + remaining characters. + - Patch #1682205: a TypeError while unpacking an iterable is no longer masked by a generic one with the message "unpack non-sequence". diff --git a/Objects/stringobject.c b/Objects/stringobject.c index 64be0de..63e1381 100644 --- a/Objects/stringobject.c +++ b/Objects/stringobject.c @@ -2344,10 +2344,10 @@ static PyObject * string_translate(PyStringObject *self, PyObject *args) { register char *input, *output; - register const char *table; + const char *table; register Py_ssize_t i, c, changed = 0; PyObject *input_obj = (PyObject*)self; - const char *table1, *output_start, *del_table=NULL; + const char *output_start, *del_table=NULL; Py_ssize_t inlen, tablen, dellen = 0; PyObject *result; int trans_table[256]; @@ -2358,9 +2358,13 @@ string_translate(PyStringObject *self, PyObject *args) return NULL; if (PyString_Check(tableobj)) { - table1 = PyString_AS_STRING(tableobj); + table = PyString_AS_STRING(tableobj); tablen = PyString_GET_SIZE(tableobj); } + else if (tableobj == Py_None) { + table = NULL; + tablen = 256; + } #ifdef Py_USING_UNICODE else if (PyUnicode_Check(tableobj)) { /* Unicode .translate() does not support the deletechars @@ -2374,7 +2378,7 @@ string_translate(PyStringObject *self, PyObject *args) return PyUnicode_Translate((PyObject *)self, tableobj, NULL); } #endif - else if (PyObject_AsCharBuffer(tableobj, &table1, &tablen)) + else if (PyObject_AsCharBuffer(tableobj, &table, &tablen)) return NULL; if (tablen != 256) { @@ -2403,7 +2407,6 @@ string_translate(PyStringObject *self, PyObject *args) dellen = 0; } - table = table1; inlen = PyString_GET_SIZE(input_obj); result = PyString_FromStringAndSize((char *)NULL, inlen); if (result == NULL) @@ -2411,7 +2414,7 @@ string_translate(PyStringObject *self, PyObject *args) output_start = output = PyString_AsString(result); input = PyString_AS_STRING(input_obj); - if (dellen == 0) { + if (dellen == 0 && table != NULL) { /* If no deletions are required, use faster code */ for (i = inlen; --i >= 0; ) { c = Py_CHARMASK(*input++); @@ -2425,8 +2428,13 @@ string_translate(PyStringObject *self, PyObject *args) return input_obj; } - for (i = 0; i < 256; i++) - trans_table[i] = Py_CHARMASK(table[i]); + if (table == NULL) { + for (i = 0; i < 256; i++) + trans_table[i] = Py_CHARMASK(i); + } else { + for (i = 0; i < 256; i++) + trans_table[i] = Py_CHARMASK(table[i]); + } for (i = 0; i < dellen; i++) trans_table[(int) Py_CHARMASK(del_table[i])] = -1; |