Strip control codes and extended characters from a string
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to strip control codes and extended characters from a string. The solution should demonstrate how to achieve each of the following results:
- a string with control codes stripped (but extended characters not stripped)
- a string with control codes and extended characters stripped
In ASCII, the control codes have decimal codes 0 through to 31 and 127. On an ASCII based system, if the control codes are stripped, the resultant string would have all of its characters within the range of 32 to 126 decimal on the ASCII table.
On a non-ASCII based system, we consider characters that do not have a corresponding glyph on the ASCII table (within the ASCII range of 32 to 126 decimal) to be an extended character for the purpose of this task.
Ada
<lang Ada>with Ada.Text_IO;
procedure Strip_ASCII is
Full: String := 'a' & Character'Val(11) & 'b' & Character'Val(166) & 'c' & Character'Val(127) & Character'Val(203) & Character'Val(202) & "de"; -- 5 ordinary characters ('a' .. 'e') -- 2 control characters (11, 127); note that 11 is the "vertical tab" -- 3 extended characters (166, 203, 202)
function Filter(S: String; From: Character := ' '; To: Character := Character'Val(126); Above: Character := Character'Val(127)) return String is begin if S'Length = 0 then return ""; elsif (S(S'First) >= From and then S(S'First) <= To) or else S(S'First) > Above then return S(S'First) & Filter(S(S'First+1 .. S'Last), From, To, Above); else return Filter(S(S'First+1 .. S'Last), From, To, Above); end if; end Filter;
procedure Put_Line(Text, S: String) is begin Ada.Text_IO.Put_Line(Text & " """ & S & """, Length:" & Integer'Image(S'Length)); end Put_Line;
begin
Put_Line("The full string :", Full); Put_Line("No Control Chars:", Filter(Full)); -- default values for From, To, and Above Put_Line("Neither_Extended:", Filter(Full, Above => Character'Last)); -- defaults for From and To
end Strip_ASCII; </lang>
Output:
The full string : "a b�c��de", Length: 10 No Control Chars: "ab�c��de", Length: 8 Neither_Extended: "abcde", Length: 5
ALGOL 68
<lang algol68># remove control characters and optionally extended characters from the string text #
- assums ASCII is the character set #
PROC strip characters = ( STRING text, BOOL strip extended )STRING:
BEGIN # we build the result in a []CHAR and convert back to a string at the end # INT text start = LWB text; INT text max = UPB text; [ text start : text max ]CHAR result; INT result pos := text start; FOR text pos FROM text start TO text max DO INT ch := ABS text[ text pos ]; IF ( ch >= 0 AND ch <= 31 ) OR ch = 127 THEN # control character # SKIP ELIF strip extended AND ( ch > 126 OR ch < 0 ) THEN # extened character and we don't want them # SKIP ELSE # include this character # result[ result pos ] := REPR ch; result pos +:= 1 FI OD; result[ text start : result pos - 1 ] END # strip characters # ;
- test the control/extended character stripping procedure #
STRING t = REPR 2 + "abc" + REPR 10 + REPR 160 + "def~" + REPR 127 + REPR 10 + REPR 150 + REPR 152 + "!"; print( ( "<<" + t + ">> - without control characters: <<" + strip characters( t, FALSE ) + ">>", newline ) ); print( ( "<<" + t + ">> - without control or extended characters: <<" + strip characters( t, TRUE ) + ">>", newline ) )</lang>
- Output:
<<�abc ádef~� ûÿ!>> - without control characters: <<abcádef~ûÿ!>> <<�abc ádef~� ûÿ!>> - without control or extended characters: <<abcdef~!>>
AutoHotkey
<lang AHK>Stripped(x){ Loop Parse, x if Asc(A_LoopField) > 31 and Asc(A_LoopField) < 128 r .= A_LoopField return r } MsgBox % stripped("`ba" Chr(00) "b`n`rc`fd" Chr(0xc3))</lang>
AWK
<lang AWK>
- syntax: GAWK -f STRIP_CONTROL_CODES_AND_EXTENDED_CHARACTERS.AWK
BEGIN {
s = "ab\xA2\x09z" # a b cent tab z printf("original string: %s (length %d)\n",s,length(s)) gsub(/[\x00-\x1F\x7F]/,"",s); printf("control characters stripped: %s (length %d)\n",s,length(s)) gsub(/[\x80-\xFF]/,"",s); printf("control and extended stripped: %s (length %d)\n",s,length(s)) exit(0)
} </lang>
output:
original string: ab¢ z (length 5) control characters stripped: ab¢z (length 4) control and extended stripped: abz (length 3)
BASIC
While DOS does support some extended characters, they aren't entirely standardized, and shouldn't be relied upon.
<lang qbasic>DECLARE FUNCTION strip$ (what AS STRING) DECLARE FUNCTION strip2$ (what AS STRING)
DIM x AS STRING, y AS STRING, z AS STRING
' tab c+cedilla eof x = CHR$(9) + "Fran" + CHR$(135) + "ais" + CHR$(26) y = strip(x) z = strip2(x)
PRINT "x:"; x PRINT "y:"; y PRINT "z:"; z
FUNCTION strip$ (what AS STRING)
DIM outP AS STRING, L0 AS INTEGER, tmp AS STRING FOR L0 = 1 TO LEN(what) tmp = MID$(what, L0, 1) SELECT CASE ASC(tmp) CASE 32 TO 126 outP = outP + tmp END SELECT NEXT strip$ = outP
END FUNCTION
FUNCTION strip2$ (what AS STRING)
DIM outP AS STRING, L1 AS INTEGER, tmp AS STRING FOR L1 = 1 TO LEN(what) tmp = MID$(what, L1, 1) SELECT CASE ASC(tmp) 'normal accented various greek, math, etc. CASE 32 TO 126, 128 TO 168, 171 TO 175, 224 TO 253 outP = outP + tmp END SELECT NEXT strip2$ = outP
END FUNCTION</lang>
Output:
x: Français→ y:Franais z:Français
See also: Liberty BASIC, PureBasic, Run BASIC
BBC BASIC
<lang bbcbasic> test$ = CHR$(9) + "Fran" + CHR$(231) + "ais." + CHR$(127)
PRINT "Original ISO-8859-1 string: " test$ " (length " ; LEN(test$) ")" test$ = FNstripcontrol(test$) PRINT "Control characters stripped: " test$ " (length " ; LEN(test$) ")" test$ = FNstripextended(test$) PRINT "Control & extended stripped: " test$ " (length " ; LEN(test$) ")" END DEF FNstripcontrol(A$) : REM CHR$(127) is a 'control' code LOCAL I% WHILE I%<LEN(A$) I% += 1 IF ASCMID$(A$,I%)<32 OR ASCMID$(A$,I%)=127 THEN A$ = LEFT$(A$,I%-1) + MID$(A$,I%+1) ENDIF ENDWHILE = A$ DEF FNstripextended(A$) LOCAL I% WHILE I%<LEN(A$) I% += 1 IF ASCMID$(A$,I%)>127 THEN A$ = LEFT$(A$,I%-1) + MID$(A$,I%+1) ENDIF ENDWHILE = A$</lang>
Output:
Original ISO-8859-1 string: Français (length 11) Control characters stripped: Français. (length 9) Control & extended stripped: Franais. (length 8)
Bracmat
<lang bracmat>( "string of ☺☻♥♦⌂, may include control characters and other ilk.\L\D§►↔◄ Rødgrød med fløde"
: ?string1 : ?string2
& :?newString & whl
' ( @(!string1:?clean (%@:<" ") ?string1) & !newString !clean:?newString )
& !newString !string1:?newString & out$(str$("Control characters stripped: " str$!newString)) & :?newString & whl
' ( @(!string2:?clean (%@:(<" "|>"~")) ?string2) & !newString !clean:?newString )
& !newString !string2:?newString & out
$ ( str $ ( "
Control characters and extended characters stripped: "
str$!newString ) )
& );</lang> Output:
Control characters stripped: string of ⌂, may include controlcharacters and other ilk.§Rødgrød med fløde Control characters and extended characters stripped: string of , may include controlcharacters and other ilk.Rdgrd med flde
C
filtered copy and swap
Take advantage of the the fact that char is an 8-bit integer in C.
Unsigned char is used throughout to enablethe extended ASCII set.
A random function is called to generate a mix of good and bad values.
A temp buffer is created with only valid characters, and swapped for the original.
A true/false function checks if the character is in the valid range.
<lang C>#include <stdlib.h>
- include <stdio.h>
- include <string.h>
- define MAXBUF 256 /* limit */
- define STR_SZ 100 /* string size */
/* function prototypes */
int ascii (const unsigned char c);
int ascii_ext (const unsigned char c);
unsigned char* strip(unsigned char* str, const size_t n, int ext );
/* check a character
return 1 for true 0 for false
- /
int ascii (const unsigned char c) {
unsigned char min = 32; /* <space> */ unsigned char max = 126; /* ~ tilde */
if ( c>=min && c<=max ) return 1;
return 0;
}
/* check if extended character
return 1 for true 0 for false
- /
int ascii_ext (const unsigned char c) {
unsigned char min_ext = 128; unsigned char max_ext = 255;
if ( c>=min_ext && c<=max_ext ) return 1;
return 0;
}
/* fill buffer with only ASCII valid characters
then rewrite string from buffer limit to n < MAX chars
- /
unsigned char* strip( unsigned char* str, const size_t n, int ext) {
unsigned char buffer[MAXBUF] = {'\0'};
size_t i = 0; // source index size_t j = 0; // dest index
size_t max = (n<MAXBUF)? n : MAXBUF -1; // limit size
while (i < max ) { if ( (ext && ascii_ext(str[i]) ) || (ascii(str[i]) ) ) // check
{ buffer[j++] = str[i]; // assign }
i++; }
memset(str, '\0', max); // wipe string
i = 0; // reset count
while( i < j) { str[i] = buffer[i]; // copy back i++; }
str[j] = '\0'; // terminate properly
return str;
}
/* try it out */ int main( int argc, char** argv) {
enum {ASCII=0, EXT=1}; /* enumeration makes easier reading */
unsigned int seed = 134529; // RNG seed value
/* variables and storage */ unsigned char badstring[STR_SZ] = {'\0'}; unsigned char bs_2[STR_SZ] = {'\0'}; unsigned char* goodstring = NULL; unsigned char* goodstring_ext = NULL;
size_t i = 0;
srand(seed); /* seed RNG */
fprintf(stdout, "Original:\t" );
/* generate a random string */ for (i = 0; i < STR_SZ; i++) { badstring[i] = (unsigned char) ( rand () & (unsigned char)0xFF ); fprintf(stdout, "%c", badstring[i] ); } fprintf(stdout, "\n");
memcpy(bs_2, badstring, STR_SZ * sizeof(unsigned char) ); /* copy string */
goodstring_ext = strip( badstring, STR_SZ, EXT); /* remove non-extended and non-ascii */
fprintf(stdout, "\nEXT:\t%s\n" , goodstring_ext );
goodstring = strip( bs_2, STR_SZ, ASCII); /* remove all non-ascii */ fprintf(stdout, "\nASCII:\t%s\n" , goodstring );
return 0; }</lang>
- Output:
Original: ƒ˜v�ý8Ç…Ø×�B„…â¤Ê8ln9V¢DèÝz�@ÅTÃ]ÊÙZ� ßÚwo�ûôÿ ¾8 ,qcζK¬0aìõ¶¯R€ˆƒ(Œ]Ÿüz›ðz;¯²GÛ#ªªÙöV z WñQŽyþ�¡
EXT: ƒ˜vý8Ç…Ø×�B„…â¤Ê8ln9V¢DèÝz@ÅTÃ]ÊÙZ ßÚwoûôÿ ¾8,qcζK¬0aìõ¶¯R€ˆƒ(Œ]Ÿüz›ðz;¯²GÛ#ªªÙöVWBþñQŽyþ¡
ASCII: v8B8ln9VDz@T]Zwo8,qcK0aR(]zz;G#VWBQy
apply mask from a table
<lang C>#include <stdio.h>
- include <stdlib.h>
- define IS_CTRL (1 << 0)
- define IS_EXT (1 << 1)
- define IS_ALPHA (1 << 2)
- define IS_DIGIT (1 << 3) /* not used, just give you an idea */
unsigned int char_tbl[256] = {0};
/* could use ctypes, but then they pretty much do the same thing */ void init_table() { int i;
for (i = 0; i < 32; i++) char_tbl[i] |= IS_CTRL; char_tbl[127] |= IS_CTRL;
for (i = 'A'; i <= 'Z'; i++) { char_tbl[i] |= IS_ALPHA; char_tbl[i + 0x20] |= IS_ALPHA; /* lower case */ }
for (i = 128; i < 256; i++) char_tbl[i] |= IS_EXT; }
/* depends on what "stripped" means; we do it in place.
* "what" is a combination of the IS_* macros, meaning strip if * a char IS_ any of them */
void strip(char * str, int what) { unsigned char *ptr, *s = (void*)str; ptr = s; while (*s != '\0') { if ((char_tbl[(int)*s] & what) == 0) *(ptr++) = *s; s++; } *ptr = '\0'; }
int main() { char a[256]; int i;
init_table();
/* populate string with one of each char */ for (i = 1; i < 255; i++) a[i - 1] = i; a[255] = '\0'; strip(a, IS_CTRL); printf("%s\n", a);
for (i = 1; i < 255; i++) a[i - 1] = i; a[255] = '\0'; strip(a, IS_CTRL | IS_EXT); printf("%s\n", a);
for (i = 1; i < 255; i++) a[i - 1] = i; a[255] = '\0'; strip(a, IS_CTRL | IS_EXT | IS_ALPHA); printf("%s\n", a);
return 0; }</lang>output:<lang> !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ <odd stuff my xterm thinks are bad unicode hence can't be properly shown>
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ !"#$%&'()*+,-./0123456789:;<=>?@[\]^_`{|}~</lang>
C#
Uses the test string from REXX. <lang csharp> using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;
namespace RosettaCode {
class Program { static void Main(string[] args) { string test = "string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄"; Console.WriteLine("Original: {0}", test); Console.WriteLine("Stripped of control codes: {0}", StripControlChars(test)); Console.WriteLine("Stripped of extended: {0}", StripExtended(test)); }
static string StripControlChars(string arg) { char[] arrForm = arg.ToCharArray(); StringBuilder buffer = new StringBuilder(arg.Length);//This many chars at most foreach(char ch in arrForm) if (!Char.IsControl(ch)) buffer.Append(ch);//Only add to buffer if not a control char
return buffer.ToString(); }
static string StripExtended(string arg) { StringBuilder buffer = new StringBuilder(arg.Length); //Max length foreach(char ch in arg) { UInt16 num = Convert.ToUInt16(ch);//In .NET, chars are UTF-16 //The basic characters have the same code points as ASCII, and the extended characters are bigger if((num >= 32u) && (num <= 126u)) buffer.Append(ch); } return buffer.ToString(); } }
} </lang> Output:
Original: string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄ Stripped of control codes: string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄ Stripped of extended: string of , may include control characters and other ilk.
C++
<lang Cpp>#include <string>
- include <iostream>
- include <algorithm>
- include <boost/lambda/lambda.hpp>
- include <boost/lambda/casts.hpp>
- include <ctime>
- include <cstdlib>
using namespace boost::lambda ;
struct MyRandomizer {
char operator( )( ) { return static_cast<char>( rand( ) % 256 ) ; }
} ;
std::string deleteControls ( std::string startstring ) {
std::string noControls( " " ) ;//creating space for //the standard algorithm remove_copy_if std::remove_copy_if( startstring.begin( ) , startstring.end( ) , noControls.begin( ) ,
ll_static_cast<int>( _1 ) < 32 && ll_static_cast<int>( _1 ) == 127 ) ;
return noControls ;
}
std::string deleteExtended( std::string startstring ) {
std::string noExtended ( " " ) ;//same as above std::remove_copy_if( startstring.begin( ) , startstring.end( ) , noExtended.begin( ) ,
ll_static_cast<int>( _1 ) > 127 || ll_static_cast<int>( _1 ) < 32 ) ;
return noExtended ;
}
int main( ) {
std::string my_extended_string ; for ( int i = 0 ; i < 40 ; i++ ) //we want the extended string to be 40 characters long my_extended_string.append( " " ) ; srand( time( 0 ) ) ; std::generate_n( my_extended_string.begin( ) , 40 , MyRandomizer( ) ) ; std::string no_controls( deleteControls( my_extended_string ) ) ; std::string no_extended ( deleteExtended( my_extended_string ) ) ; std::cout << "string with all characters: " << my_extended_string << std::endl ; std::cout << "string without control characters: " << no_controls << std::endl ; std::cout << "string without extended characters: " << no_extended << std::endl ; return 0 ;
}</lang> Output:
string with all characters: K�O:~���7�5���� ���W��@>��ȓ�q�Q@���W- string without control characters: K�O:~���7�5���� ���W��@>��ȓ�q�Q@���W- string without extended characters: KO:~75W@>qQ@W-
Clojure
<lang clojure>; generate our test string of characters with control and extended characters (def range-of-chars (apply str (map char (range 256))))
- filter out the control characters
(apply str (filter #(not (Character/isISOControl %)) range-of-chars))
- filter to return String of characters that are between 32 - 126
(apply str (filter #(<= 32 (int %) 126) range-of-chars))</lang>
Common Lisp
(defun control-char-p (ch) (or (< (char-code ch) 32) (= (char-code ch) 127))) (defun extended-char-p (ch) (> (char-code ch) 127)) (defun strip-special-chars (string &key strip-extended) (let ((needs-removing-p (if strip-extended (lambda (ch) (or (control-char-p ch) (extended-char-p ch))) #'control-char-p))) (remove-if needs-removing-p string)))
D
<lang d>import std.traits;
S stripChars(S)(S s, bool function(dchar) pure nothrow mustStrip)
pure nothrow if (isSomeString!S) { S result; foreach (c; s) { if (!mustStrip(c)) result ~= c; } return result;
}
void main() {
import std.stdio, std.uni; auto s = "\u0000\u000A abc\u00E9def\u007F"; writeln(s.stripChars( &isControl )); writeln(s.stripChars( c => isControl(c) || c == '\u007F' )); writeln(s.stripChars( c => isControl(c) || c >= '\u007F' ));
}</lang>
- Output:
abcédef� abcédef abcdef
Erlang
Exported functions to be used by Update_a_configuration_file <lang Erlang> -module( strip_control_codes ).
-export( [is_not_control_code/1, is_not_control_code_nor_extended_character/1, task/0] ).
is_not_control_code( C ) when C > 127 -> true; is_not_control_code( C ) when C < 32; C =:= 127 -> false; is_not_control_code( _C ) -> true.
is_not_control_code_nor_extended_character( C ) when C > 127 -> false; is_not_control_code_nor_extended_character( C ) -> is_not_control_code( C ).
task() ->
String = lists:seq( 0, 255 ), io:fwrite( "String (~p characters): ~s~n", [erlang:length(String), String] ), String_without_cc = lists:filter( fun is_not_control_code/1, String ), io:fwrite( "String without control codes (~p characters): ~s~n", [erlang:length(String_without_cc), String_without_cc] ), String_without_cc_nor_ec = lists:filter( fun is_not_control_code_nor_extended_character/1, String ), io:fwrite( "String without control codes nor extended characters (~p characters): ~s~n", [erlang:length(String_without_cc_nor_ec), String_without_cc_nor_ec] ).
</lang>
- Output:
41> strip_control_codes:task(). String (256 characters): ^@^A^B^C^D^E^F^G^H ^N^O^P^Q^R^S^T^U^V^W^X^Y^Z^[^\^]^^^_ !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~^�������������������������������� ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ String without control codes (223 characters): !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~�������������������������������� ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ String without control codes nor extended characters (95 characters): !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
F#
Uses test string from REXX. <lang fsharp> open System
let stripControl (arg:string) =
String(Array.filter (fun x -> not (Char.IsControl(x))) (arg.ToCharArray()))
//end stripControl
let stripExtended (arg:string) =
let numArr = Array.map (fun (x:char) -> Convert.ToUInt16(x)) (arg.ToCharArray()) in String([|for num in numArr do if num >= 32us && num <= 126us then yield Convert.ToChar(num) |])
//end stripExtended
[<EntryPoint>] let main args =
let test = "string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄" printfn "Original: %s" test printfn "Stripped of controls: %s" (stripControl test) printfn "Stripped of extended: %s" (stripExtended test) 0//main must return integer, much like in C/C++
</lang> Output:
Original: string of ☺☻♥♦�, may include control characters and other ilk.♫☼§►↔◄ Stripped of controls: string of ☺☻♥♦�, may include control characters and other ilk.♫☼§►↔◄ Stripped of extended: string of , may include control characters and other ilk.
Factor
<lang>USING: ascii kernel sequences ;
- strip-control-codes ( str -- str' ) [ control? not ] filter ;
- strip-control-codes-and-extended ( str -- str' )
strip-control-codes [ ascii? ] filter ;</lang>
Forth
<lang forth>: strip ( buf len -- buf len' ) \ repacks buffer, so len' <= len
over + over swap over ( buf dst limit src ) do i c@ 32 127 within if i c@ over c! char+ then loop over - ;</lang>
Fortran
<lang fortran>module stripcharacters implicit none
contains
pure logical function not_control(ch) character, intent(in) :: ch not_control = iachar(ch) >= 32 .and. iachar(ch) /= 127 end function not_control
pure logical function not_extended(ch) character, intent(in) :: ch not_extended = iachar(ch) >= 32 .and. iachar(ch) < 127 end function not_extended
pure function strip(string,accept) result(str) character(len=*), intent(in) :: string character(len=len(string)) :: str interface pure logical function accept(ch) character, intent(in) :: ch end function except end interface integer :: i,n str = repeat(' ',len(string)) n = 0 do i=1,len(string) if ( accept(string(i:i)) ) then n = n+1 str(n:n) = string(i:i) end if end do end function strip
end module stripcharacters
program test
use stripcharacters character(len=256) :: string, str integer :: ascii(256), i forall (i=0:255) ascii(i) = i forall (i=1:len(string)) string(i:i) = achar(ascii(i)) write (*,*) string write (*,*) 'Control characters deleted:' str = strip(string,not_control) write (*,*) str
forall (i=1:len(string)) string(i:i) = achar(ascii(i)) write (*,*) 'Extended characters deleted:' write (*,*) strip(string,not_extended)
end program test </lang>
FreeBASIC
<lang freebasic>' FB 1.05.0 Win64
Function stripControlChars(s As Const String) As String
If s = "" Then Return "" Dim count As Integer = 0 Dim strip(0 To Len(s) - 1) As Boolean For i As Integer = 0 To Len(s) - 1 For j As Integer = 0 To 31 If s[i] = j OrElse s[i] = 127 Then count += 1 strip(i) = True Exit For End If Next j Next i
Dim buffer As String = Space(Len(s) - count) count = 0 For i As Integer = 0 To Len(s) - 1 If Not Strip(i) Then buffer[count] = s[i] count += 1 End If Next Return buffer
End Function
Function stripExtendedChars(s As Const String) As String
If s = "" Then Return "" Dim count As Integer = 0 Dim strip(0 To Len(s) - 1) As Boolean For i As Integer = 0 To Len(s) - 1 For j As Integer = 128 To 255 If s[i] = j Then count += 1 strip(i) = True Exit For End If Next j Next i
Dim buffer As String = Space(Len(s) - count) count = 0 For i As Integer = 0 To Len(s) - 1 If Not Strip(i) Then buffer[count] = s[i] count += 1 End If Next Return buffer
End Function
Dim s As String = !"\v\001The\t quick\255 \vbrown\127\f fox\156" Dim s1 As String = stripControlChars(s) Dim s2 As String = stripExtendedChars(s) Dim s3 As String = stripExtendedChars(s1)
' Under Windows console, code page 850 : ' "vertical tab" displays as ♂ ' "form feed" displays as ♀ ' Chr(1) displays as ☺ ' Chr(127) displays as ⌂ ' the other control characters do what it says on the tin ' Chr(156) displays as £ ' Chr(255) displays as space
Print "Before stripping :" , s Print "Ctl chars stripped :" , s1 Print "Ext chars stripped :" , s2 Print "Both sets stripped :" , s3 Print Print "Before stripping" , "Length => " ; Len(s) Print "Ctl chars stripped" , "Length => " ; Len(s1) Print "Ext chars stripped" , "Length => " ; Len(s2) Print "Both sets stripped" , "Length => " ; Len(s3) Print Print "Press any key to quit" Sleep</lang>
- Output:
Before stripping : ♂☺The quick ♂brown⌂♀ fox£ Ctl chars stripped : The quick brown fox£ Ext chars stripped : ♂☺The quick ♂brown⌂♀ fox Both sets stripped : The quick brown fox Before stripping Length => 27 Ctl chars stripped Length => 21 Ext chars stripped Length => 25 Both sets stripped Length => 19
Gambas
Click this link to run this code <lang gambas>Public Sub Main() Dim sString As String = "The\t \equick\n \fbrownfox \vcost £125.00 or €145.00 or $160.00 \bto \ncapture ©®" Dim sStd, sExtend As String Dim siCount As Short
For siCount = 32 To 126
sStd &= Chr(siCount)
Next
For siCount = 128 To 255
sExtend &= Chr(siCount)
Next
Print "Original string: -\t" & sString & gb.NewLine Print "No extended characters: -\t" & Check(sString, sStd) sStd &= sExtend Print "With extended characters: -\t" & Check(sString, sStd)
End '________________________________________________________________ Public Sub Check(sString As String, sCheck As String) As String Dim siCount As Short Dim sResult As String
For siCount = 1 To Len(sString)
If InStr(sCheck, Mid(sString, siCount, 1)) Then sResult &= Mid(sString, siCount, 1)
Next
Return sResult
End</lang> Output:
Original string: - The uick brownfox ^Kcost £125.00 or €145.00 or $160.00to capture ©® No extended characters: - The quick brownfox cost 125.00 or 145.00 or $160.00 to capture With extended characters: - The quick brownfox cost £125.00 or €145.00 or $160.00 to capture ©®
Go
Go works for ASCII and non-ASCII systems. The first pair of functions below interpret strings as byte strings, presumably useful for strings consisting of ASCII and 8-bit extended ASCII data. The second pair of functions interpret strings as UTF-8. <lang go>package main
import ( "golang.org/x/text/transform" "golang.org/x/text/unicode/norm" "fmt" "strings" )
// two byte-oriented functions identical except for operator comparing c to 127. func stripCtlFromBytes(str string) string { b := make([]byte, len(str)) var bl int for i := 0; i < len(str); i++ { c := str[i] if c >= 32 && c != 127 { b[bl] = c bl++ } } return string(b[:bl]) }
func stripCtlAndExtFromBytes(str string) string { b := make([]byte, len(str)) var bl int for i := 0; i < len(str); i++ { c := str[i] if c >= 32 && c < 127 { b[bl] = c bl++ } } return string(b[:bl]) }
// two UTF-8 functions identical except for operator comparing c to 127 func stripCtlFromUTF8(str string) string { return strings.Map(func(r rune) rune { if r >= 32 && r != 127 { return r } return -1 }, str) }
func stripCtlAndExtFromUTF8(str string) string { return strings.Map(func(r rune) rune { if r >= 32 && r < 127 { return r } return -1 }, str) }
// Advanced Unicode normalization and filtering, // see http://blog.golang.org/normalization and // http://godoc.org/golang.org/x/text/unicode/norm for more // details. func stripCtlAndExtFromUnicode(str string) string { isOk := func(r rune) bool { return r < 32 || r >= 127 } // The isOk filter is such that there is no need to chain to norm.NFC t := transform.Chain(norm.NFKD, transform.RemoveFunc(isOk)) // This Transformer could also trivially be applied as an io.Reader // or io.Writer filter to automatically do such filtering when reading // or writing data anywhere. str, _, _ = transform.String(t, str) return str }
const src = "déjà vu" + // precomposed unicode "\n\000\037 \041\176\177\200\377\n" + // various boundary cases "as⃝df̅" // unicode combining characters
func main() { fmt.Println("source text:") fmt.Println(src) fmt.Println("\nas bytes, stripped of control codes:") fmt.Println(stripCtlFromBytes(src)) fmt.Println("\nas bytes, stripped of control codes and extended characters:") fmt.Println(stripCtlAndExtFromBytes(src)) fmt.Println("\nas UTF-8, stripped of control codes:") fmt.Println(stripCtlFromUTF8(src)) fmt.Println("\nas UTF-8, stripped of control codes and extended characters:") fmt.Println(stripCtlAndExtFromUTF8(src)) fmt.Println("\nas decomposed and stripped Unicode:") fmt.Println(stripCtlAndExtFromUnicode(src)) }</lang> Output: (varies with display configuration)
source text: déjà vu � !~��� as⃝df̅ as bytes, stripped of control codes: déjà vu !~��as⃝df̅ as bytes, stripped of control codes and extended characters: dj vu !~asdf as UTF-8, stripped of control codes: déjà vu !~��as⃝df̅ as UTF-8, stripped of control codes and extended characters: dj vu !~asdf as decomposed and stripped Unicode: deja vu !~asdf
Groovy
<lang Groovy>def stripControl = { it.replaceAll(/\p{Cntrl}/, ) } def stripControlAndExtended = { it.replaceAll(/[^\p{Print}]/, ) }</lang> Test: <lang Groovy>def text = (0..255).collect { (char) it }.join() def textMinusControl = text.findAll { int v = (char)it; v > 31 && v != 127 }.join() def textMinusControlAndExtended = textMinusControl.findAll {((char)it) < 128 }.join()
assert stripControl(text) == textMinusControl assert stripControlAndExtended(text) == textMinusControlAndExtended</lang>
Haskell
<lang Haskell>import Control.Applicative (liftA2)
strip, strip2 :: String -> String strip = filter (liftA2 (&&) (> 31) (< 126) . fromEnum)
-- or strip2 = filter (((&&) <$> (> 31) <*> (< 126)) . fromEnum)
main :: IO () main =
(putStrLn . unlines) $ [strip, strip2] <*> ["alphabetic 字母 with some less parochial parts"]</lang>
- Output:
alphabetic with some less parochial parts alphabetic with some less parochial parts
Icon and Unicon
We'll use deletec to remove unwanted characters (2nd argument) from a string (1st argument). The procedure below coerces types back and forth between string and cset. The character set of unwanted characters is the difference of all ASCII characters and the ASCII characters from 33 to 126. <lang Icon>procedure main(A) write(image(deletec(&ascii,&ascii--(&ascii)[33:127]))) end link strings </lang>
The IPL procedure deletec is equivalent to this: <lang Icon>procedure deletec(s, c) #: delete characters
result := "" s ? { while result ||:= tab(upto(c)) do tab(many(c)) return result ||:= tab(0) }
end</lang>
Output:
" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}"
J
Solution: <lang j>stripControlCodes=: -.&(DEL,32{.a.) stripControlExtCodes=: ([ -. -.)&(32}.127{.a.)</lang> Usage: <lang j> mystring=: a. {~ ?~256 NB. ascii chars 0-255 in random order
#mystring NB. length of string
256
#stripControlCodes mystring NB. length of string without control codes
223
#stripControlExtCodes mystring NB. length of string without control codes or extended chars
95
#myunicodestring=: u: ?~1000 NB. unicode characters 0-999 in random order
1000
#stripControlCodes myunicodestring
967
#stripControlExtCodes myunicodestring
95
stripControlExtCodes myunicodestring
k}w:]U3xEh9"GZdr/#^B.Sn%\uFOo[(`t2-J6*IA=Vf&N;lQ8,${XLz5?D0~s)'Y7Kq|ip4<WRCaM!b@cgv_T +mH>1ejPy</lang>
Java
<lang java>import java.util.function.IntPredicate;
public class StripControlCodes {
public static void main(String[] args) { String s = "\u0000\n abc\u00E9def\u007F"; System.out.println(stripChars(s, c -> c > '\u001F' && c != '\u007F')); System.out.println(stripChars(s, c -> c > '\u001F' && c < '\u007F')); }
static String stripChars(String s, IntPredicate include) { return s.codePoints().filter(include::test).collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString(); }
}</lang>
abcédef abcdef
JavaScript
ES 5
<lang JavaScript>(function (strTest) {
// s -> s function strip(s) { return s.split().filter(function (x) { var n = x.charCodeAt(0); return 31 < n && 127 > n; }).join(); }
return strip(strTest);
})("\ba\x00b\n\rc\fd\xc3");</lang>
- Output:
<lang JavaScript>"abcd"</lang>
jq
<lang jq>def strip_control_codes:
explode | map(select(. > 31 and . != 127)) | implode;
def strip_extended_characters:
explode | map(select(31 < . and . < 127)) | implode;</lang>
Example: <lang jq>def string: "string of ☺☻♥♦⌂, may include control characters such as null(\u0000) and other ilk.\n§►↔◄\nRødgrød med fløde";
"string | strip_control_codes\n => \(string | strip_control_codes)", "string | strip_extended_characters\n => \(string | strip_extended_characters)"</lang>
- Output:
<lang sh>$ jq -n -r -f Strip_control_codes_and_extended_characters.jq string | strip_control_codes
=> string of ☺☻♥♦⌂, may include control characters such as null() and other ilk.§►↔◄Rødgrød med fløde
string | strip_extended_characters
=> string of , may include control characters such as null() and other ilk.Rdgrd med flde</lang>
Julia
<lang Julia> stripc0{T<:String}(a::T) = replace(a, r"[\x00-\x1f\x7f]", "") stripc0x{T<:String}(a::T) = replace(a, r"[^\x20-\x7e]", "")
a = "a\n\tb\u2102d\u2147f"
println("Original String:\n ", a) println("\nWith C0 control characters removed:\n ", stripc0(a)) println("\nWith C0 and extended characters removed:\n ", stripc0x(a)) </lang>
- Output:
Original String: a bℂdⅇf With C0 control characters removed: abℂdⅇf With C0 and extended characters removed: abdf
Kotlin
<lang scala>// version 1.1.2
fun String.strip(extendedChars: Boolean = false): String {
val sb = StringBuilder() for (c in this) { val i = c.toInt() if (i in 32..126 || (!extendedChars && i >= 128)) sb.append(c) } return sb.toString()
}
fun main(args: Array<String>) {
println("Originally:") val s = "123\tabc\u0007DEF\u007F+-*/€æŧðłþ" println("String = $s Length = ${s.length}") println("\nAfter stripping control characters:") val t = s.strip() println("String = $t Length = ${t.length}") println("\nAfter stripping control and extended characters:") val u = s.strip(true) println("String = $u Length = ${u.length}")
}</lang>
- Output:
Originally: String = 123 abcDEF�+-*/€æŧðłþ Length = 22 After stripping control characters: String = 123abcDEF+-*/€æŧðłþ Length = 19 After stripping control and extended characters: String = 123abcDEF+-*/ Length = 13
langur
<lang langur>val .str = "()\x15abcd\uFFFF123\uBBBB!@#$%^&*\x01"
writeln "original : ", .str writeln "without ctrl chars: ", replace(.str, RE/\p{Cc}/, ZLS) writeln "print ASCII only : ", replace(.str, re/[^ -~]/, ZLS)</lang>
- Output:
original : ()�abcd�123뮻!@#$%^&*� without ctrl chars: ()abcd�123뮻!@#$%^&* print ASCII only : ()abcd123!@#$%^&*
Liberty BASIC
<lang lb>
all$ ="" for i =0 to 255 all$ =all$ +chr$( i) next i
print "Original string of bytes. ( chr$( 10) causes a CRLF.)" print all$ print
lessControl$ =controlStripped$( all$) print "With control codes stripped out." print lessControl$ print
lessExtendedAndControl$ =extendedStripped$( lessControl$) print "With extended codes stripped out too." print lessExtendedAndControl$
end
function controlStripped$( i$) r$ ="" for j =1 to len( i$) ch$ =mid$( i$, j, 1) if asc( ch$) >=32 then r$ =r$ +ch$ next j controlStripped$ =r$ end function
function extendedStripped$( i$) r$ ="" for j =1 to len( i$) ch$ =mid$( i$, j, 1) if asc( ch$) <=128 then r$ =r$ +ch$ next j extendedStripped$ =r$ end function
</lang>
Lua
<lang lua>function Strip_Control_Codes( str )
local s = "" for i in str:gmatch( "%C+" ) do s = s .. i end return s
end
function Strip_Control_and_Extended_Codes( str )
local s = "" for i = 1, str:len() do
if str:byte(i) >= 32 and str:byte(i) <= 126 then
s = s .. str:sub(i,i)
end
end return s
end
q = "" for i = 0, 255 do q = q .. string.char(i) end
print( Strip_Control_Codes(q) ) print( Strip_Control_and_Extended_Codes(q) )</lang>
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~€�‚ƒ„…†‡ˆ‰Š‹Œ�Ž��‘’“”•–—˜™š›œ�žŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
Mathematica
<lang Mathematica>stripCtrl[x_]:=StringJoin[Select[Characters[x], MemberQ[CharacterRange["!","~"]~Join~Characters[FromCharacterCode[Range[128,255]]],#]&]]
stripCtrlExt[x_]:=StringJoin[Select[Characters[x], MemberQ[CharacterRange["!","~"],#]&]]</lang>
Test:
CompleteSet=FromCharacterCode[Range[0,255]] ->\.00\.02\.03\.04\.05\.06\.07\.08\.0b\.0e\.0f\.10\.11\.12\.13\.14 \.15\.16\.17\.18\.19\.1a\[RawEscape]\.1c\.1d\.1e\.1f !"#$%&'()*+,-./ 0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\] ^_`abcdefghijklmnopqrstuvwxyz{|}~��������������������������������� ¡¢£¤¥¦§¨©ª«\[Not]®¯\[Degree] \[PlusMinus]\.b2\.b3\.b4\[Micro]\[Paragraph]\[CenterDot]¸¹º»¼½¾¿ ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ*ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö/øùúûüýþÿ stripCtrl[CompleteSet] ->!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\] ^_`abcdefghijklmnopqrstuvwxyz{|}~�������������������������������� ¡¢£¤¥¦§¨©ª«\[Not]®¯\[Degree] \[PlusMinus]\.b2\.b3\.b4\[Micro]\[Paragraph]\[CenterDot] ¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ*ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö /øùúûüýþÿ stripCtrlExt[CompleteSet] ->!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\] ^_`abcdefghijklmnopqrstuvwxyz{|}~
MATLAB / Octave
<lang MATLAB> function str = stripped(str)
str = str(31<str & str<127); end; </lang>
Nim
<lang nim>proc stripped(str: string): string =
result = "" for c in str: if ord(c) in 32..126: result.add c
proc strippedControl(str: string): string =
result = "" for c in str: if ord(c) in {32..126, 128..255}: result.add c
echo strippedControl "\ba\x00b\n\rc\fdÄ" echo stripped "\ba\x00b\n\rc\fd\xc3"</lang> Output:
abcdÄ abcd
OCaml
<lang ocaml>let is_control_code c =
let d = int_of_char c in d < 32 || d = 127
let is_extended_char c =
let d = int_of_char c in d > 127
let strip f str =
let len = String.length str in let res = Bytes.create len in let rec aux i j = if i >= len then Bytes.to_string (Bytes.sub res 0 j) else if f str.[i] then aux (succ i) j else begin Bytes.set res j str.[i]; aux (succ i) (succ j) end in aux 0 0
let () =
Random.self_init (); let len = 32 in let s = String.init len (fun _ -> char_of_int (Random.int 256)) in print_endline (strip is_control_code s); print_endline (strip (fun c -> (is_control_code c) || (is_extended_char c)) s);
- </lang>
Pascal
<lang pascal>program StripCharacters(output);
function Strip (s: string; control, extended: boolean): string;
var index: integer; begin Strip := ; for index:= 1 to length(s) do if not ((control and (ord(s[index]) <= 32)) or (extended and (ord(s[index]) > 127))) then Strip := Strip + s[index]; end;
var
test: string; i: integer;
begin
setlength(test, 40); randomize; for i := 1 to length(test) do test[i] := char(1 + random(255)); writeln ('Original: ', test); writeln ('No CNTL: ', Strip(test, true, false)); writeln ('No extnd: ', Strip(test, false, true)); writeln ('ASCII: ', Strip(test, true, true));
end.</lang> Output:
% ./StripCharacters Original: )?z8i9?a?K??N?s?F˪w?a??s #?b?B}PT?ٜ No CNTL: )?z8i9?a?K??N?s?F˪w?a??s#?b?B}PT?ٜ No extnd: )z8i9aKNsFwas #bB}PT ASCII: )z8i9aKNsFwas#bB}PT
Peloton
Peloton has a native instruction for removing control codes from a string, SAL, the Low ASCII Strip. From the manual: <lang sgml>Create variable with control characters: <@ SAYLETVARLIT>i|This string has control characters - - - - - -
in it</@> Strip control characters <@ SAYSALVAR>i</@> Assign infix <@ LETVARSALVAR>j|i</@> <@ SAYVAR>j</@> Assign prepend <@ LETSALVARVAR>k|i</@> <@ SAYVAR>k</@> Reflexive assign <@ ACTSALVAR>i</@> <@ SAYVAR>i</@></lang>
Peloton also has SAH, High ASCII Strip. Again, from the manual: <lang sgml>Create variable with high and low ANSI: <@ SAYLETVARLIT>i|This string has both low ansi and high ansi characters - il doit d'être prévenu</@> Strip high ANSI <@ SAYSAHVAR>i</@> Assign infix <@ LETVARSAHVAR>j|i</@> <@ SAYVAR>j</@> Assign prepend <@ LETSAHVARVAR>k|i</@> <@ SAYVAR>k</@> Reflexive assign <@ ACTSAHVAR>i</@> <@ SAYVAR>i</@></lang>
Perl
<lang Perl>#!/usr/bin/perl -w use strict ;
my @letters ; my @nocontrols ; my @noextended ; for ( 1..40 ) {
push @letters , int( rand( 256 ) ) ;
} print "before sanitation : " ; print join( , map { chr( $_ ) } @letters ) ; print "\n" ; @nocontrols = grep { $_ > 32 && $_ != 127 } @letters ; print "Without controls: " ; print join( , map { chr( $_ ) } @nocontrols ) ; @noextended = grep { $_ < 127 } @nocontrols ; print "\nWithout extended: " ; print join( , map { chr( $_ ) } @noextended ) ; print "\n" ;</lang> Output:
before sanitation : �L08&YH�O��n)�:���O�G$���.���"zO���Q�?�� Without controls: �L08&YH�O��n)�:�O�G$���.���"zO��Q�?�� Without extended: L08&YHOn):OG$."zOQ?
Phix
While you can delete a character from a string using say s[i..i] = "", the fastest and easiest way is always just
to build a new one character-by-character.
I've credited Ada solely for the sensible fromch/toch/abovech idea.
<lang Phix>function filter(string s, integer fromch=' ', toch=#7E, abovech=#7F)
string res = ""
for i=1 to length(s) do integer ch = s[i] if ch>=fromch and (ch<=toch or ch>abovech) then res &= ch end if end for return res
end function
procedure put_line(string text, s)
printf(1,"%s \"%s\", Length:%d\n",{text,s,length(s)})
end procedure
string full = "\u0000 abc\u00E9def\u007F"
put_line("The full string:", full) put_line("No Control Chars:", filter(full)) -- default values for fromch, toch, and abovech put_line("\" and no Extended:", filter(full, abovech:=#FF)) -- defaults for fromch and toch</lang>
- Output:
The full string: " abc+®def�", Length:11 No Control Chars: " abc+®def", Length:9 " and no Extended: " abcdef", Length:7
PicoLisp
Control characters in strings are written with a hat (^) in PicoLisp. ^? is the DEL character. <lang PicoLisp>(de stripCtrl (Str)
(pack (filter '((C) (nor (= "^?" C) (> " " C "^A")) ) (chop Str) ) ) )
(de stripCtrlExt (Str)
(pack (filter '((C) (> "^?" C "^_")) (chop Str) ) ) )</lang>
Test:
: (char "^?") -> 127 : (char "^_") -> 31 : (stripCtrl "^I^M a b c^? d äöüß") -> " a b c d äöüß" : (stripCtrlExt "^I^M a b c^? d äöüß") -> " a b c d "
Pike
<lang Pike>> string input = random_string(100); > (string)((array)input-enumerate(32)-enumerate(255-126,1,127)); Result: "p_xx08M]cK<FHgR3\\I.x>)Tm<VgakYddy&P7"</lang>
PL/I
<lang PL/I> stripper: proc options (main);
declare s character (100) varying; declare i fixed binary;
s = 'the quick brown fox jumped'; /* A loop to replace blanks with control characters */ do i = 1 to length(s); if substr(s, i, 1) = ' ' then substr(s, i, 1) = '01'x; end; put skip list (s);
call stripcc (s); put skip list (s);
s = 'now is the time for all good men'; /* A loop to replace blanks with control characters */ do i = 1 to length(s); if substr(s, i, 1) = ' ' then substr(s, i, 1) = 'A1'x; end; put skip list (s);
call stripex (s); put skip list (s);
/* Strip control codes. */ stripcc: procedure (s);
declare s character (*) varying; declare w character (length(s)); declare c character (1); declare (i, j) fixed binary;
j = 0; do i = 1 to length (s); c = substr(s, i, 1); if unspec(c) >= '00100000'b | unspec(c) = '01111111'b then do; j = j + 1; substr(w, j, 1) = c; end; end; s = substr(w, 1, j);
end stripcc;
/* Strips control codes and extended characters. */ stripex: procedure (s);
declare s character (*) varying; declare w character (length(s)); declare c character (1); declare (i, j) fixed binary;
j = 0; do i = 1 to length (s); c = substr(s, i, 1); if unspec(c) >= '00100000'b & unspec(c) < '01111111'b then do; j = j + 1; substr(w, j, 1) = c; end; end; s = substr(w, 1, j);
end stripex;
end stripper; </lang> Output:
the�quick�brown�fox�jumped thequickbrownfoxjumped now¡is¡the¡time¡for¡all¡good¡men nowisthetimeforallgoodmen
PowerShell
<lang PowerShell> function Remove-Character {
[CmdletBinding(DefaultParameterSetName="Control and Extended")] [OutputType([string])] Param ( [Parameter(Mandatory=$true, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true, Position=0)] [string] $String,
[Parameter(ParameterSetName="Control")] [switch] $Control,
[Parameter(ParameterSetName="Extended")] [switch] $Extended )
Begin { filter Remove-ControlCharacter { $_.ToCharArray() | ForEach-Object -Begin {$out = ""} -Process {if (-not [Char]::IsControl($_)) {$out += $_ }} -End {$out} }
filter Remove-ExtendedCharacter { $_.ToCharArray() | ForEach-Object -Begin {$out = ""} -Process {if ([int]$_ -lt 127) {$out += $_ }} -End {$out} } } Process { foreach ($s in $String) { switch ($PSCmdlet.ParameterSetName) { "Control" {$s | Remove-ControlCharacter} "Extended" {$s | Remove-ExtendedCharacter} Default {$s | Remove-ExtendedCharacter | Remove-ControlCharacter} } } }
} </lang>
<lang PowerShell> $test = "$([char]9)Français."
"Original string : `"$test`"" "Control characters stripped : `"$($test | Remove-Character -Control)`"" "Extended characters stripped : `"$($test | Remove-Character -Extended)`"" "Control & extended stripped : `"$($test | Remove-Character)`"" </lang>
- Output:
Original string : " Français." Control characters stripped : "Français." Extended characters stripped : " Franais." Control & extended stripped : "Franais."
<lang PowerShell> "Français", "Čeština" | Remove-Character -Extended </lang>
- Output:
Franais etina
PureBasic
<lang PureBasic>Procedure.s stripControlCodes(source.s)
Protected i, *ptrChar.Character, length = Len(source), result.s *ptrChar = @source For i = 1 To length If *ptrChar\c > 31 result + Chr(*ptrChar\c) EndIf *ptrChar + SizeOf(Character) Next ProcedureReturn result
EndProcedure
Procedure.s stripControlExtCodes(source.s)
Protected i, *ptrChar.Character, length = Len(source), result.s *ptrChar = @source For i = 1 To length If *ptrChar\c > 31 And *ptrChar\c < 128 result + Chr(*ptrChar\c) EndIf *ptrChar + SizeOf(Character) Next ProcedureReturn result
EndProcedure
If OpenConsole()
;create sample string Define i, s.s For i = 1 To 80 s + Chr(Random(254) + 1) ;include character values from 1 to 255 Next
PrintN(stripControlCodes(s)) ;string without control codes PrintN("---------") PrintN(stripControlExtCodes(s)) ;string without control codes or extended chars Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole()
EndIf</lang> Sample output:
»╫=┐C─≡G(═ç╤â√╝÷╔¬ÿ▌x è4∞|)ï└⌐ƒ9²òτ┌ºáj)▓<~-vPÿφQ╨ù¿╖îFh"[ü╗dÉ₧q#óé├p╫■ --------- =CG(x 4|)9j)<~-vPQFh"[dq#p
Python
<lang Python>stripped = lambda s: "".join(i for i in s if 31 < ord(i) < 127)
print(stripped("\ba\x00b\n\rc\fd\xc3"))</lang>Output:<lang>abcd</lang>
Racket
<lang Racket>
- lang racket
- Works on both strings (Unicode) and byte strings (raw/ASCII)
(define (strip-controls str)
(regexp-replace* #rx"[\0-\037\177]+" str ""))
(define (strip-controls-and-extended str)
(regexp-replace* #rx"[^\040-\176]+" str ""))
</lang>
Raku
(formerly Perl 6)
<lang perl6>my $str = (0..400).roll(80)».chr.join;
say $str; say $str.subst(/<:Cc>/, , :g); # unicode property: control character say $str.subst(/<-[\ ..~]>/, , :g);</lang>
kşaNĹĭŗ�|Ęw���"ÄlĄWł8iCƁę��Ż�¬�5ĎĶ'óü¸'ÍŸ;ŢƐ¦�´ŷQċűÒŴ$ÃŅ�Đįð+=ĥƂ+Ōĭħ¼ŕc¤H~ìïēÕ kşaNĹĭŗ|Ęw"ÄlĄWł8iCƁ꯬5ĎĶ'óü¸'ÍŸ;ŢƐ¦´ŷQċűÒŴ$ÃŅĐįð+=ĥƂ+Ōĭħ¼ŕc¤H~ìïēÕ kaN|w"lW8iC5'';Q$+=+cH~
REXX
Note that guillemets were used as fences in presenting/displaying the «««before»»» and «««after»»» text strings.
idiomatic version
This REXX version processes each character in an idiomatic way (if it's a wanted character, then keep it). <lang rexx>/*REXX program strips all "control codes" from a character string (ASCII or EBCDIC). */ z= 'string of ☺☻♥♦⌂, may include control characters and other ♫☼§►↔◄░▒▓█┌┴┐±÷²¬└┬┘ilk.' @=' !"#$%&()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~' $=
do j=1 for length(z); _=substr(z, j, 1) /*get a char from X one at a time. */ if verify(_, @)==0 then $=$ || _ /*Is char in the @ list? Then use it.*/ end /*j*/ /*stick a fork in it, we're all done. */
say 'old = »»»'z"«««" /*add ««fence»» before & after old text*/ say 'new = »»»'$"«««" /* " " " " " new " */</lang>
- output:
old = »»»string of ☺☻♥♦⌂, may include control characters and other ♫☼§►↔◄░▒▓█┌┴┐±÷²¬└┬┘ilk.««« new = »»»string of , may include control characters and other ilk.«««
faster version
This REXX version only deletes unwanted characters.
It also shows a different way of performing concatenations (without using abutments, and a way to split a long literal (character) string.
Because there are (or should be) fewer unwanted characters than wanted characters, this version is faster. <lang rexx>/*REXX program strips all "control codes" from a character string (ASCII or EBCDIC). */ x= 'string of ☺☻♥♦⌂, may include control characters and other ♫☼§►↔◄░▒▓█┌┴┐±÷²¬└┬┘ilk.' @=' !"#$%&()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghij' || ,
'klmnopqrstuvwxyz{|}~'
$=x /*set "new" string to same as the old. */
do until _=0; _=verify($, @) /*check if any character isn't in @.*/ if _\==0 then $=delstr($, _, 1) /*Is this a bad char? Then delete it.*/ end /*until*/ /*stick a fork in it, we're all done. */
say 'old = »»»' || x || "«««" /*add ««fence»» before & after old text*/ say 'new = »»»' || $ || "«««" /* " " " " " new " */</lang>
- output is identical to the 1st REXX version.
Ring
<lang ring> s = char(31) + "abc" + char(13) + "def" + char(11) + "ghi" + char(10) see strip(s) + nl
func strip str strip = "" for i = 1 to len(str)
nr = substr(str,i,1) a = ascii(nr) if a > 31 and a < 123 and nr != "'" and nr != """" strip = strip + nr ok
next return strip </lang>
Ruby
<lang ruby>class String
def strip_control_characters() chars.each_with_object("") do |char, str| str << char unless char.ascii_only? and (char.ord < 32 or char.ord == 127) end end def strip_control_and_extended_characters() chars.each_with_object("") do |char, str| str << char if char.ascii_only? and char.ord.between?(32,126) end end
end
p s = "\ba\x00b\n\rc\fd\xc3\x7ffoo" p s.strip_control_characters p s.strip_control_and_extended_characters</lang>
- Output:
"\ba\u0000b\n\rc\fd\xC3\u007Ffoo" "abcd\xC3foo" "abcdfoo"
Run BASIC
<lang runbasic>s$ = chr$(31) + "abc" + chr$(13) + "def" + chr$(11) + "ghi" + chr$(10) print strip$(s$)
' ----------------------------------------- ' strip junk ' ----------------------------------------- FUNCTION strip$(str$) for i = 1 to len(str$)
a$ = MID$(str$,i,1) a = ASC(a$) if a > 31 then if a < 123 then if a$ <> "'" then if a$ <> """" then strip$ = strip$ + a$ end if end if end if end if
next i END FUNCTION</lang>
input : chr$(31)+"abc"+chr$(13)+"def"+chr$(11)+"ghi"+chr$(10) output : abcdefghi
Scala
ASCII: Using StringOps Class
<lang Scala>val controlCode : (Char) => Boolean = (c:Char) => (c <= 32 || c == 127) val extendedCode : (Char) => Boolean = (c:Char) => (c <= 32 || c > 127)
// ASCII test...
val teststring = scala.util.Random.shuffle( (1.toChar to 254.toChar).toList ).mkString
println( "ctrl filtered out: \n\n" +
teststring.filterNot(controlCode) + "\n" )
println( "ctrl and extended filtered out: \n\n" +
teststring.filterNot(controlCode).filterNot(extendedCode) + "\n" )</lang>
- Output:
ctrl filtered out: ?d2??6ú╖)ⁿ┼gEhW3RS⌠!a?┬╘├╢-ß?·▄╔B,_?╟│┤'C║j«?ΩcqJ╣²▀÷±?0s∩░uτ8Φ½&Σ¬y▓H?*?AL?═eDX??≥╚╧ 4σ+r=Ѽ╙U▌"?.⌐?≡K?k╥áF\?╕QΘ?╪Z?▐√╠?`M?7▒°G^≈@xz?>t:╦╨íw¿─┐]Io(V╡?P¡┴?º┌ΓO┘φ└╓~|#⌡π?}µ ╗l???$ó{n/╫mi╤<9f≤?∙»Nª;?1??εT?■╩%╒╛[╜p∞α╬vñ╞bYδ╝5█ ctrl and extended filtered out: ?d26)gEhW3RS!a-B,_'CjcqJ0su8&yH*ALeDX4+r=U".KkF \QZ`M7G^@xz>t:w]Io(VPO~|#}l${n/mi<9fN;1T%[pvbY5
Unicode: Using Regular Expressions
<lang Scala>// // A Unicode test string // val ulist = 0x8232.toChar :: 0xFFF9.toChar :: 0x200E.toChar :: (1.toChar to 2000.toChar).toList val ustring = scala.util.Random.shuffle( ulist ).mkString
// Remove control codes including private codes val sNoCtrlCode = ustring.replaceAll("[\\p{C}]","")
val htmlNoCtrlCode = for( i <- sNoCtrlCode.indices ) yield
"&#" + sNoCtrlCode(i).toInt + ";" + (if( (i+1) % 10 == 0 ) "\n" else "")
println( "ctrl filtered out:
\n\n" + htmlNoCtrlCode.mkString + "
\n" )
// Keep 0x00-0x7f and remove control codes
val sNoExtCode = ustring.replaceAll("[^\\p{InBasicLatin}]","").replaceAll("[\\p{C}]","")
val htmlNoExtCode = for( i <- sNoExtCode.indices ) yield
"&#" + sNoExtCode(i).toInt + ";" + (if( (i+1) % 10 == 0 ) "\n" else "")
println( "ctrl and extended filtered out:
\n\n" + htmlNoExtCode.mkString + "
\n" )</lang>
- Output:
ctrl filtered out: Қ۳ҹؽݠČǗ ɄخȿѻȺ·˖ҎDװѩԸץ˶٤ǞĽۭԑϣʱƁΫیոϐۛؕƟͱӄצ ݞÄҺϤΪq͆ݶȲֆ֫՞ѡ٘ٺ݅ݦϠ۸ܞЕ²ɋډҒӂȏϘʚΧ˾ܡȳևՋƖדȇހڷ ӣ؊ՙ̨۟ۀĦ¬ς݇؛ĿΟՕƜ1ԵۣݬͮDŽ̪عڔЊڳœӟѺ՜ʬΚ݀͗̾ʊáLJѪ ٹȭםޮɅ֜ʼݥޤڎۊŭЁ˹īʶñۼ[ӽه:3ŜSԛģó͑؝Јי̅ݏˬˮіۍ PԅMѯԶɔܺ֘ݷԾڽˎΞn̏ŗۧ˒ޥϷDžŀ˳Ѡ̮ݕũۃɹƾފѼܚٍڢŽܛńի ߀CžʾʹքӭξҖҢǘZ<ɼÐՅ̔ݧئ٫ʖѬ̩ߌǿɇݻ÷ђΤǀёՓJѦϻΥ¨̦ڥ ˍ͖٭зݡѧס̶̵¯ȐƌޭԮϙҦ+ڦÇ֍ɽƥЦ۩ǦҠêʧɮð̣̯ޘƭƠͺޠݩγ ѳ֊НۜÚӺϭ̃ݵƬŇЎٛԪճɟЩЋֱϜޒfޓʨܮɱղŬέǏu։Ҹ˅رɾʘͅ ߃¾ª"ɖȾύƔýՈԉգȨڼۮ͍õŘ]àߊܱЫҴٗԞۢ ˂ہƞɺƚ۞ҤڻƸǵǯ ܄ʠƲťïܠmТϋɥΈώͶ٢ؖټ\Ŵˣé֔ڤÿϛσ߂Λøʞӿăմ؉ϪЗպƓ҆܀ݰ ѹΏɨғڲƀɞԗ26Ĕŵ³ѥ͛ǨՄǓĻڊʝӹʍ̠ϰʄՍə܅лġޏnj˴ʃ۵Ϻdž ՟Ҽ̈۹ԺߎМރѵ͋ؾЇѐ|ԨةݝɕǕڴljȩþؐ؆j˿ق۽ɳОѷęijٯÂěȴ ˓חګ٠ޅךćءɉӢɗчЉő͜Ѐ֨ےϸܽԀ»эјۇޣ֤Ґ͊ȫއɒۓ۷́ضӖΙَБ ×ʳҧЅȗUƅŷÈɸȕ܆ĵޖȁɢӼԒѢխǖ@ǡȰўҍГӛº۾ף˔ъͣʏ«ћڏ حǟΖԕƑǼթٸe֦ʗސڍƙКԻ̿ιü̧´փϱʤܭηƷѨЮԭѿ¢ßݚؒ٪ҩʢں` ۠μưɍӉØN̬ވƘȈ֎ǝٙӷΨи¥еοݫ̷Ɨ?ͰĹ֝ݸ_؇Àׁ̌ûʥĭȶǍԔ үơ̕ג˗ϑӤӰ'άܶѮĀشڱӻǻܼƿ܉ͪѰܑ̓K~Ұ֮πҬʷ˫ۯٿpВ̥ տؓЍܒ˲ӥɰާڜԫ͎ϿűӈϦƤڣʓƎѱޛяâޱƻЄÃ̸ـ̂֕Ӛ̗֣ͬӦ݄ۑƦܖ ߄ɷۉڨȑձІȖƯٵۡуħۦِ̱ԢɑФ١̺دʂsչ.ۋҾėè˭ٷbϮݱݔǩʈ ȻiͫϯԦĚػţ܍եֿχ݂ت܁լɀгޙȥʼnˈՇݣ̰ӊɩɲȢәNJȬ֙׀ݼŏكЭ ʒױ̼љфȃHՖ؟҂̢ʕʲƼްӀŁڄ˼ȅԙÙ7ّſۘ٩ȱ֟ƕ͕ʆŚͼօ°؈>ݺ ... ctrl and extended filtered out: Dq1[:3SPMnCZ<J+fu"]m\26|jU@e`N?_'K~ps.biH7>zAXVF5 =OgBhYGc-4)E/*a,%wTLoR&W{kd}8l^;0#(!trvIx$Qy9
Seed7
Seed7 strings are UTF-32 encoded, therefore no destinction between BYTE and Unicode strings is necessary. The example below uses STD_UTF8_OUT from the library utf8.s7i, to write Unicode characters with UTF-8 encoding to the console.
<lang seed7>$ include "seed7_05.s7i";
include "utf8.s7i";
const func string: stripControl (in string: stri) is func
result var string: stripped is ""; local var integer: old_pos is 1; var integer: index is 0; var char: ch is ' '; begin for ch key index range stri do if ch < ' ' or ch = '\127;' then stripped &:= stri[old_pos .. pred(index)]; old_pos := succ(index); end if; end for; stripped &:= stri[old_pos ..]; end func;
const func string: stripControlAndExtended (in string: stri) is func
result var string: stripped is ""; local var integer: old_pos is 1; var integer: index is 0; var char: ch is ' '; begin for ch key index range stri do if ch < ' ' or ch >= '\127;' then stripped &:= stri[old_pos .. pred(index)]; old_pos := succ(index); end if; end for; stripped &:= stri[old_pos ..]; end func;
const string: src is "déjà vu\ # Unicode
\\n\0;\31; \33;\126;\127;\128;\255;\n\ # Various boundary cases \as⃝df̅"; # Unicode combining characters
const proc: main is func
begin OUT := STD_UTF8_OUT; writeln("source text:"); writeln(src); writeln("Stripped of control codes:"); writeln(stripControl(src)); writeln("Stripped of control codes and extended characters:"); writeln(stripControlAndExtended(src)); end func;</lang>
Output:
source text: déjà vu � !~��ÿ as⃝df̅ Stripped of control codes: déjà vu !~�ÿas⃝df̅ Stripped of control codes and extended characters: dj vu !~asdf
Sidef
<lang ruby>var str = "\ba\x00b\n\rc\fd\xc3\x7ffoo"
var letters = str.chars.map{.ord} say letters.map{.chr}.join.dump
var nocontrols = letters.grep{ (_ > 32) && (_ != 127) } say nocontrols.map{.chr}.join.dump
var noextended = nocontrols.grep{ _ < 127 } say noextended.map{.chr}.join.dump</lang>
- Output:
"\ba\0b\n\rc\fd\xC3\x7Ffoo" "abcd\xC3foo" "abcdfoo"
Tcl
<lang tcl>proc stripAsciiCC str {
regsub -all {[\u0000-\u001f\u007f]+} $str ""
} proc stripCC str {
regsub -all {[^\u0020-\u007e]+} $str ""
}</lang>
TI-83 BASIC
TI-83 BASIC doesn't support ASCII or Unicode, so the following program just strips every character that doesn't have a corresponding glyph from 32 to 126 decimal in a real ASCII table.
The following "normal characters" do exist, but can't be typed on the calculator and a hex editor must be used to enter them:
<lang ti83b>#$&@;_`abcdefghijklmnopqrstuvwxyz|~</lang>
The double quote character (ASCII decimal 34) can be entered, but cannot be escaped and thus cannot be stored to strings without the use of hex editors. The following program will remove double quotes from the input string if they were hacked in simply because having one stored to the "check" string is syntactically invalid.
So, in sum, you have to hack the calculator to enter in this program, but once it's entered you can transfer it to unhacked calculators and it will work.
<lang ti83b>:" !#$%&'()*+,-./0123456789:;<=>?ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~"→Str0
- Input ">",Str1
- ":"+Str1+":"→Str1
- For(I,2,length(Str1)-2)
- If not(inString(Str0,sub(Str1,I,1)))
- sub(Str1,1,I-1)+sub(Str1,I+1,length(Str1)-(I+1))→Str1
- End
- sub(Str1,2,length(Str1)-1)→Str1
- Pause Str1</lang>
TXR
<lang txrlisp>(defun strip-controls (str)
(regsub #/[\x0-\x1F\x7F]+/ "" str))
(defun strip-controls-and-extended (str)
(regsub #/[^\x20-\x7F]+/ "" str))</lang>
VBScript
Derived from the BASIC version. <lang vb> Function StripCtrlCodes(s) tmp = "" For i = 1 To Len(s) n = Asc(Mid(s,i,1)) If (n >= 32 And n <= 126) Or n >=128 Then tmp = tmp & Mid(s,i,1) End If Next StripCtrlCodes = tmp End Function
Function StripCtrlCodesExtChrs(s) tmp = "" For i = 1 To Len(s) n = Asc(Mid(s,i,1)) If n >= 32 And n <= 126 Then tmp = tmp & Mid(s,i,1) End If Next StripCtrlCodesExtChrs = tmp End Function
WScript.StdOut.Write "ab�cd�ef�gh�€" & " = " & StripCtrlCodes("ab�cd�ef�gh�€") WScript.StdOut.WriteLine WScript.StdOut.Write "ab�cd�ef�gh�ij†klð€" & " = " & StripCtrlCodesExtChrs("ab�cd�ef�gh�ij†klð€") WScript.StdOut.WriteLine </lang>
- Output:
ab�cd�ef�gh�€ = abcdefgh€ ab�cd�ef�gh�ij†klð€ = abcdefghijkl
Wren
<lang ecmascript>import "/pattern" for Pattern
var s = "\t\n\r\x01\0\fabc\v\v\b\a\x1f\x7f🌇Páez😃É"
// strip control codes only var p = Pattern.new("+1/c") var r = p.replaceAll(s, "") System.print("%(r) -> length %(r.count)")
// strip extended characters as well p = Pattern.new("[+1/c|/R]") r = p.replaceAll(s, "") System.print("%(r) -> length %(r.count)") </lang>
- Output:
abc🌇Páez😃É -> length 10 abcPez -> length 6
XPL0
<lang XPL0>include c:\cxpl\codes; \intrinsic 'code' declarations string 0; \use zero-terminated string convention
proc Strip(Str, Both); \Strip out control and optionally extended chars char Str; int Both; int I, J, C; [I:= 0; while Str(I) do
[C:= Str(I); if Both then C:= extend(C); \if stripping extended chars too, extend sign if C<$20 or C=$7F then [J:= I; \eliminate char by shifting string down over it repeat C:= Str(J+1); Str(J):= C; J:= J+1; until C=0; ] else I:= I+1; ];
];
char String; [String:= "Hello^M^J World àáâã"; Text(0, String); CrLf(0); Strip(String, false); Text(0, String); CrLf(0); Strip(String, true); Text(0, String); CrLf(0); ]</lang>
Output:
Hello World àáâã Hello World àáâã Hello World
zkl
ASCII <lang zkl>var ctlCodes=([1..31].pump(String,"toChar") +(127).toChar()); var extdChars=[127..255].pump(String,"toChar");
var test = "string of ☺☻♥♦⌂, control characters(\t\b\e) and other ilk.♫☼§►↔◄"; test.println("<< test string"); (test-ctlCodes).println("<< no control chars"); (test-extdChars).println("<< no extended chars"); (test-extdChars-ctlCodes).println("<< text"); </lang>
- Output:
string of ☺☻♥♦⌂, control characters( and other ilk.♫☼§►↔◄<< test string string of ☺☻♥♦⌂, control characters() and other ilk.♫☼§►↔◄<< no control chars string of , control characters(and other ilk.<< no extended chars string of , control characters() and other ilk.<< text
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