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 edf24a4e2f621ff49f8c7e42cb364331b1afbdec..afa0787eca6ffb32ec1c7fd540b4eebcd1abc7a3 100644 (file)
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -254,23 +254,37 @@ def expandtabs(s, tabsize=8):
        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 edf24a4e2f621ff49f8c7e42cb364331b1afbdec..afa0787eca6ffb32ec1c7fd540b4eebcd1abc7a3 100644 (file)
--- a/Lib/stringold.py
+++ b/Lib/stringold.py
@@ -254,23 +254,37 @@ def expandtabs(s, tabsize=8):
        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 069d5f444799a800cab488ecfbf500ee7dffc734..7e44e0ee6320e364f32abcfb5dd7dfc698fb5b95 100644 (file)
--- a/Modules/stropmodule.c
+++ b/Modules/stropmodule.c
@@ -547,30 +547,78 @@ strop_atof(self, args)
 }
 
 
+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 @@ static struct methodlist strop_methods[] = {
        {"splitfields", strop_splitfields, 1},
        {"strip",       strop_strip},
        {"swapcase",    strop_swapcase},
+       {"maketrans",   strop_maketrans, 1},
        {"translate",   strop_translate, 1},
        {"upper",       strop_upper},
        {NULL,          NULL}   /* sentinel */