Added 3rd optional argument to translate(), a string of characters to delete.
Added maketrans(), a utility to create a translation table.
diff --git a/Lib/string.py b/Lib/string.py
index edf24a4..afa0787 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -254,23 +254,37 @@
return res + line
# Character translation through look-up table.
-def translate(s, table):
- if type(table) != type('') or len(table) != 256:
- raise TypeError, "translation table must be 256-char string"
- res = ""
- for c in s:
- res = res + table[ord(c)]
- return res
+def translate(s, table, deletions=""):
+ if type(table) != type('') or len(table) != 256:
+ raise TypeError, "translation table must be 256 characters long"
+ res = ""
+ for c in s:
+ if c not in deletions:
+ res = res + table[ord(c)]
+ return res
# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
def capitalize(s):
- return upper(s[:1]) + lower(s[1:])
+ return upper(s[:1]) + lower(s[1:])
# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
# See also regsub.capwords().
def capwords(s):
- return join(map(capitalize, split(s)))
+ return join(map(capitalize, split(s)))
+# Construct a translation string
+_idmapL = None
+def maketrans(fromstr, tostr):
+ if len(fromstr) != len(tostr):
+ raise ValueError, "maketrans arguments must have same length"
+ global _idmapL
+ if not _idmapL:
+ _idmapL = map(None, _idmap)
+ L = _idmapL[:]
+ fromstr = map(ord, fromstr)
+ for i in range(len(fromstr)):
+ L[fromstr[i]] = tostr[i]
+ return joinfields(L, "")
# Try importing optional built-in module "strop" -- if it exists,
# it redefines some string operations that are 100-1000 times faster.
diff --git a/Lib/stringold.py b/Lib/stringold.py
index edf24a4..afa0787 100644
--- a/Lib/stringold.py
+++ b/Lib/stringold.py
@@ -254,23 +254,37 @@
return res + line
# Character translation through look-up table.
-def translate(s, table):
- if type(table) != type('') or len(table) != 256:
- raise TypeError, "translation table must be 256-char string"
- res = ""
- for c in s:
- res = res + table[ord(c)]
- return res
+def translate(s, table, deletions=""):
+ if type(table) != type('') or len(table) != 256:
+ raise TypeError, "translation table must be 256 characters long"
+ res = ""
+ for c in s:
+ if c not in deletions:
+ res = res + table[ord(c)]
+ return res
# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
def capitalize(s):
- return upper(s[:1]) + lower(s[1:])
+ return upper(s[:1]) + lower(s[1:])
# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
# See also regsub.capwords().
def capwords(s):
- return join(map(capitalize, split(s)))
+ return join(map(capitalize, split(s)))
+# Construct a translation string
+_idmapL = None
+def maketrans(fromstr, tostr):
+ if len(fromstr) != len(tostr):
+ raise ValueError, "maketrans arguments must have same length"
+ global _idmapL
+ if not _idmapL:
+ _idmapL = map(None, _idmap)
+ L = _idmapL[:]
+ fromstr = map(ord, fromstr)
+ for i in range(len(fromstr)):
+ L[fromstr[i]] = tostr[i]
+ return joinfields(L, "")
# Try importing optional built-in module "strop" -- if it exists,
# it redefines some string operations that are 100-1000 times faster.
diff --git a/Modules/stropmodule.c b/Modules/stropmodule.c
index 069d5f4..7e44e0e 100644
--- a/Modules/stropmodule.c
+++ b/Modules/stropmodule.c
@@ -547,30 +547,78 @@
}
+static PyObject *
+strop_maketrans(self, args)
+ PyObject *self; /* Not used */
+ PyObject *args;
+{
+ unsigned char c[256], *from=NULL, *to=NULL;
+ int i, fromlen=0, tolen=0;
+
+ if (PyTuple_Size(args)!=0) {
+ if (!PyArg_ParseTuple(args, "s#s#", &from, &fromlen,
+ &to, &tolen))
+ return NULL;
+ }
+
+ if (fromlen!=tolen) {
+ PyErr_SetString(ValueError,
+ "maketrans arguments must have same length");
+ return NULL;
+ }
+ for(i=0; i<256; i++)
+ c[i]=(unsigned char)i;
+ for(i=0; i<fromlen; i++) {
+ c[from[i]]=to[i];
+ }
+ return PyString_FromStringAndSize((char *)c, 256);
+}
+
+
static object *
strop_translate(self, args)
object *self;
object *args;
{
- char *input, *table, *output;
- int inlen, tablen;
- object *result;
- int i;
+ char *input, *table, *output, *output_start, *delete=NULL;
+ int inlen, tablen, dellen;
+ PyObject *result;
+ int i, trans_table[256];
- if (!newgetargs(args, "s#s#", &input, &inlen, &table, &tablen))
+ if (!PyArg_ParseTuple(args, "s#s#|s#", &input, &inlen,
+ &table, &tablen, &delete, &dellen))
return NULL;
if (tablen != 256) {
- err_setstr(ValueError,
+ PyErr_SetString(ValueError,
"translation table must be 256 characters long");
return NULL;
}
- result = newsizedstringobject((char *)NULL, inlen);
+ for(i=0; i<256; i++)
+ trans_table[i]=Py_CHARMASK(table[i]);
+ if (delete!=NULL) {
+ for(i=0; i<dellen; i++)
+ trans_table[delete[i]]=-1;
+ }
+
+ result = PyString_FromStringAndSize((char *)NULL, inlen);
if (result == NULL)
return NULL;
- output = getstringvalue(result);
- for (i = 0; i < inlen; i++) {
- int c = Py_CHARMASK(*input++);
- *output++ = table[c];
+ output_start = output = PyString_AsString(result);
+ if (delete!=NULL && dellen!=0) {
+ for (i = 0; i < inlen; i++) {
+ int c = Py_CHARMASK(*input++);
+ if (trans_table[c]!=-1)
+ *output++ = (char)trans_table[c];
+ }
+ /* Fix the size of the resulting string */
+ if (inlen > 0 &&_PyString_Resize(&result, output-output_start))
+ return NULL;
+ } else {
+ /* If no deletions are required, use a faster loop */
+ for (i = 0; i < inlen; i++) {
+ int c = Py_CHARMASK(*input++);
+ *output++ = (char)trans_table[c];
+ }
}
return result;
}
@@ -592,6 +640,7 @@
{"splitfields", strop_splitfields, 1},
{"strip", strop_strip},
{"swapcase", strop_swapcase},
+ {"maketrans", strop_maketrans, 1},
{"translate", strop_translate, 1},
{"upper", strop_upper},
{NULL, NULL} /* sentinel */