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Strip control codes and extended characters from a string

From Rosetta Code
Task
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[edit]

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;
 

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[edit]

# 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 ) )
Output:
<<�abc
ádef~?
ûÿ!>> - without control characters:             <<abcádef~ûÿ!>>
<<�abc
ádef~?
ûÿ!>> - without control or extended characters: <<abcdef~!>>

AutoHotkey[edit]

Translation of: Python
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))

AWK[edit]

 
# 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)
}
 

output:

original string: ab¢    z (length 5)
control characters stripped: ab¢z (length 4)
control and extended stripped: abz (length 3)

BASIC[edit]

Works with: QBasic

While DOS does support some extended characters, they aren't entirely standardized, and shouldn't be relied upon.

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

Output:

x:      Français→
y:Franais
z:Français

See also: Liberty BASIC, PureBasic, Run BASIC

BBC BASIC[edit]

      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$

Output:

Original ISO-8859-1 string:  Français (length 11)
Control characters stripped: Français. (length 9)
Control & extended stripped: Franais. (length 8)

Bracmat[edit]

(  "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
)
)
& );

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[edit]

#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;
}
output:
 !"#$%&'()*+,-./0123456789:;<=>[email protected][\]^_`abcdefghijklmnopqrstuvwxyz{|}~ <odd stuff my xterm thinks are bad unicode hence can't be properly shown>
 !"#$%&'()*+,-./0123456789:;<=>[email protected][\]^_`abcdefghijklmnopqrstuvwxyz{|}~
 !"#$%&'()*+,-./0123456789:;<=>?@[\]^_`{|}~

C++[edit]

#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 ;
}

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-    

C#[edit]

Uses the test string from REXX.

 
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();
}
}
}
 

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.

Clojure[edit]

; 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))

Common Lisp[edit]

> (defparameter *extended-ascii* (coerce (loop for i from 0 to 255 collect (code-char i)) 'string))

*EXTENDED-ASCII*
> (defparameter *control-codes-stripped* 
    (remove-if #'(lambda (c) 
                   (let ((x (char-code c)))
                     (or (< x 32) (= x 127))))
               *extended-ascii*))

*CONTROL-CODES-STRIPPED*
> *control-codes-stripped*

" !\"#$%&'()*+,-./0123456789:;<=>[email protected][\\][email protected][email protected]ùúûüýþÿ"
> (defparameter *control-codes-and-extended-stripped* 
    (remove-if-not #'(lambda (c) (and (standard-char-p c) (graphic-char-p c)))
                   *extended-ascii*))

*CONTROL-CODES-AND-EXTENDED-STRIPPED*
> *control-codes-and-extended-stripped*

" !\"#$%&'()*+,-./0123456789:;<=>[email protected][\\]^_`abcdefghijklmnopqrstuvwxyz{|}~"

D[edit]

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' ));
}
Output:
 abcédef?
 abcédef
 abcdef

Erlang[edit]

Exported functions to be used by Update_a_configuration_file

 
-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] ).
 
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:;<=>[email protected][\][email protected][email protected][email protected][email protected]óôõö÷øùúûüýþÿ
String without control codes (223 characters):  !"#$%&'()*+,-./0123456789:;<=>[email protected][\][email protected][email protected][email protected][email protected]óôõö÷øùúûüýþÿ
String without control codes nor extended characters (95 characters):  !"#$%&'()*+,-./0123456789:;<=>[email protected][\]^_`abcdefghijklmnopqrstuvwxyz{|}~

F#[edit]

Uses test string from REXX.

 
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++
 

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.

Forth[edit]

: 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 - ;

Fortran[edit]

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
 

FreeBASIC[edit]

' 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
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

Go[edit]

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.

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))
}

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[edit]

def stripControl = { it.replaceAll(/\p{Cntrl}/, '') }
def stripControlAndExtended = { it.replaceAll(/[^\p{Print}]/, '') }

Test:

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

Haskell[edit]

strip :: String -> String
strip =
filter
(\x -- Though use of Data.Char functions like isAlpha, isDigit etc
-- seems more probable.
->
let o = fromEnum x
in o > 31 && o < 126)
 
main :: IO ()
main = print $ strip "alphabetic 字母 with some less parochial parts"
Output:
"alphabetic  with some less parochial parts"

Icon and Unicon[edit]

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.

procedure main(A)
write(image(deletec(&ascii,&ascii--(&ascii)[33:127])))
end
link strings
 

strings.icn provides deletec

The IPL procedure deletec is equivalent to this:

procedure deletec(s, c)			#: delete characters
result := ""
s ? {
while result ||:= tab(upto(c)) do tab(many(c))
return result ||:= tab(0)
}
end


Output:
" !\"#$%&'()*+,-./0123456789:;<=>[email protected][\\]^_`abcdefghijklmnopqrstuvwxyz{|}"

J[edit]

Solution:

stripControlCodes=: -.&(DEL,32{.a.)
stripControlExtCodes=: ([ -. -.)&(32}.127{.a.)

Usage:

   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<[email protected]_T +mH>1ejPy

JavaScript[edit]

ES 5[edit]

(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");
Output:
"abcd"

Java[edit]

Works with: Java version 8+
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();
}
}
 abcédef
 abcdef

jq[edit]

Works with: jq version 1.4
def strip_control_codes:
explode | map(select(. > 31 and . != 127)) | implode;
 
def strip_extended_characters:
explode | map(select(31 < . and . < 127)) | implode;

Example:

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)"
Output:
$ 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

Julia[edit]

 
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))
 
Output:
Original String:
    a
        bℂdⅇf

With C0 control characters removed:
    abℂdⅇf

With C0 and extended characters removed:
    abdf

Liberty BASIC[edit]

 
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
 

Lua[edit]

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) )
 !"#$%&'()*+,-./0123456789:;<=>[email protected][\][email protected][email protected][email protected][email protected]êëìíîïðñòóôõö÷øùúûüýþÿ
 !"#$%&'()*+,-./0123456789:;<=>[email protected][\]^_`abcdefghijklmnopqrstuvwxyz{|}~

Mathematica[edit]

stripCtrl[x_]:=StringJoin[Select[Characters[x],
MemberQ[CharacterRange["!","~"]~Join~Characters[FromCharacterCode[Range[128,255]]],#]&]]
 
stripCtrlExt[x_]:=StringJoin[Select[Characters[x],
MemberQ[CharacterRange["!","~"],#]&]]

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\[RawEscape]\.1c\.1d\.1e\.1f !"#$%&'()*+,-./
0123456789:;<=>[email protected][\]
[email protected]‘’“”•–—˜™š›œžŸ ¡¢£¤¥¦§¨©ª«\[Not]­®¯\[Degree]
\[PlusMinus]\.b2\.b3\.b4\[Micro]\[Paragraph]\[CenterDot]¸¹º»¼½¾¿
ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ*ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö/øùúûüýþÿ

stripCtrl[CompleteSet]
->!"#$%&'()*+,-./0123456789:;<=>[email protected][\]
[email protected]‘’“”•–—˜™š›œžŸ ¡¢£¤¥¦§¨©ª«\[Not]­®¯\[Degree]
\[PlusMinus]\.b2\.b3\.b4\[Micro]\[Paragraph]\[CenterDot]
¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ*ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö
/øùúûüýþÿ

stripCtrlExt[CompleteSet]
->!"#$%&'()*+,-./0123456789:;<=>[email protected][\]
^_`abcdefghijklmnopqrstuvwxyz{|}~


MATLAB / Octave[edit]

 function str = stripped(str)
str = str(31<str & str<127);
end;

Nim[edit]

proc stripped(str): string =
result = ""
for c in str:
if ord(c) in 32..126:
result.add c
 
echo stripped "\ba\x00b\n\rc\fd\xc3"

Output:

abcd

OCaml[edit]

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 = String.create len in
let rec aux i j =
if i >= len then String.sub res 0 j else
if f str.[i]
then aux (succ i) j
else begin
res.[j] <- str.[i];
aux (succ i) (succ j)
end
in
aux 0 0
 
let () =
let len = 32 in
let s = String.create len in
Random.self_init();
for i = 0 to pred len do
s.[i] <- char_of_int (Random.int 256)
done;
print_endline (strip is_control_code s);
print_endline (strip (fun c -> (is_control_code c) || (is_extended_char c)) s);
;;

Pascal[edit]

Works with: Free_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.

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[edit]

Peloton has a native instruction for removing control codes from a string, SAL, the Low ASCII Strip. From the manual:

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</@>

Peloton also has SAH, High ASCII Strip. Again, from the manual:

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</@>

Perl[edit]

#!/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" ;

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?

Perl 6[edit]

my $str = (0..400).roll(80)».chr.join;
 
say $str;
say $str.subst(/<[ ^@..^_ ]>/, '', :g);
say $str.subst(/<-[ \ ..~ ]>/, '', :g);
�¶ØèúđkƌĘ�r­=êıƏÄÙÍy1SGa%TÑ�ęMŒRŅ�EŧİÌŬ–ńĩµ9ŒďĔÜÉĈĬz‰ijdś5FúŨƏźƅíýÛÃņGÏ
                                                                      ö~šƀ‹RÑú›
¶ØèúđkƌĘr­=êıƏÄÙÍy1SGa%TÑęMŒRŅEŧİÌŬ–ńĩµ9ŒďĔÜÉĈĬz‰ijdś5FúŨƏźƅíýÛÃņGÏö~šƀ‹RÑú›
kr=y1SGa%TMRE9zd5FG~R

PicoLisp[edit]

Control characters in strings are written with a hat (^) in PicoLisp. ^? is the DEL character.

(de stripCtrl (Str)
(pack
(filter
'((C)
(nor (= "^?" C) (> " " C "^A")) )
(chop Str) ) ) )
 
(de stripCtrlExt (Str)
(pack
(filter
'((C) (> "^?" C "^_"))
(chop Str) ) ) )

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[edit]

> 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"

PL/I[edit]

 
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;
 

Output:

the�quick�brown�fox�jumped 
thequickbrownfoxjumped 
now¡is¡the¡time¡for¡all¡good¡men 
nowisthetimeforallgoodmen 

PowerShell[edit]

 
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}
}
}
}
}
 
 
$test = "$([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)`""
 
Output:
Original string              : "	Français."
Control characters stripped  : "Français."
Extended characters stripped : "	Franais."
Control & extended stripped  : "Franais."
 
"Français", "Čeština" | Remove-Character -Extended
 
Output:
Franais
etina

PureBasic[edit]

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

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[edit]

stripped = lambda s: "".join(i for i in s if 31 < ord(i) < 127)
 
print(stripped("\ba\x00b\n\rc\fd\xc3"))
Output:
abcd

Racket[edit]

 
#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 ""))
 

REXX[edit]

using translate[edit]

(Both versions support ASCII and EBCDIC.)

This version is much faster, but it's much harder to understand what's happening.

/*REXX program strips all  "control codes"  from a character string  (ASCII or EBCDIC). */
xxx= 'string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄'
/*in EBCDIC, the digit 1 is 'f1'x, */
/* " ASCII, " " " " 31'x. */
ebcdic= (1=='f1'x) /*is this an EBCDIC computer ? */
/*generate a string of characters from */
/*'00'x ──► [1 just before the blank].*/
ccChars = xrange(,d2c(c2d(' ') -1)) /*generate a range of characters. */
if \ebcdic then ccChars=ccChars'7f'x /*add the ASCII '7f'X character. */
say 'hex ccChars =' c2x(ccChars) /*might as well do a display of ccChars*/
ccCharsX = ccChars'ff'x /*add a "stop" character for ccCharsX*/
 
_stop= substr(ccCharsX,verify(ccCharsX, xxx), 1) /*find a "stop" character. */
yyy = translate(space(translate(xxx, _stop, " "ccChars), 0), , _stop)
 
say 'old = »»»'xxx"«««" /*add ««fence»» before & after old text*/
say 'new = »»»'yyy"«««" /* " " " " " new " */
/*stick a fork in it, we're all done. */

output   when run on an ASCII machine:

hex ccChars = 000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F7F
old = »»»string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄«««
new = »»»string of , may include control characters and other ilk.«««

using DO loop[edit]

(Both versions support ASCII and EBCDIC.)

A slower version, but it's much easier to understand the process.

/*REXX program strips all  "control codes"  from a character string  (ASCII or EBCDIC). */
xxx= 'string of ☺☻♥♦⌂, may include control characters and other ilk.♫☼§►↔◄'
/*in EBCDIC, the digit 1 is 'f1'x, */
/* " ASCII, " " " " 31'x. */
ascii= ('31'x==1) /*is this an ASCII computer? */
/*generate a string of characters from */
/*'00'x ──► [1 just before the blank].*/
ccChars = xrange(, d2c(c2d(' ') -1) ) /*generate a range of characters. */
if ascii then ccChars=ccChars'7f'x /*add the ASCII '7f'X character. */
say 'hex ccChars =' c2x(ccChars) /*might as well do a display of ccChars*/
yyy= /*start with a clean slate. */
do j=1 for length(xxx) /*build a new string, 1 byte at a time.*/
_=substr(xxx, j, 1) /*get next character in the old string.*/
if pos(_, ccChars)\==0 then iterate /*skip this character, it's a no-no. */
yyy = yyy || _ /*we found a good and decent character.*/
end
 
say 'old = »»»'xxx"«««" /*add ««fence»» before & after old text*/
say 'new = »»»'yyy"«««" /* " " " " " new " */
/*stick a fork in it, we're all done. */

output   is identical to the 1st REXX version when run on an ASCII machine.

Ring[edit]

 
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
 

Ruby[edit]

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
Output:
"\ba\u0000b\n\rc\fd\xC3\u007Ffoo"
"abcd\xC3foo"
"abcdfoo"

Run BASIC[edit]

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
input  : chr$(31)+"abc"+chr$(13)+"def"+chr$(11)+"ghi"+chr$(10)
output : abcdefghi


Scala[edit]

ASCII: Using StringOps Class[edit]

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" )
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\[email protected]?>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
\[email protected]>t:w]Io(VPO~|#}l${n/mi<9fN;1T%[pvbY5

Unicode: Using Regular Expressions[edit]

//
// 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: <br/><br/>\n\n" + htmlNoCtrlCode.mkString + "<br/><br/>\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: <br/><br/>\n\n" + htmlNoExtCode.mkString + "<br/><br/>\n" )
Output:
ctrl filtered out:

Қ۳ҹؽݠČǗ ɄخȿѻȺ·˖ҎDװѩԸץ˶٤ǞĽۭԑϣʱƁΫیոϐۛؕƟͱӄצ
ݞÄҺϤΪq͆ݶȲֆ֫՞ѡ٘ٺ݅ݦϠ۸ܞЕ²ɋډҒӂȏϘʚΧ˾ܡȳևՋƖדȇހڷ
ӣ؊ՙ̨۟ۀĦ¬ς݇؛ĿΟՕƜ1ԵۣݬͮDŽ̪عڔЊڳœӟѺ՜ʬΚ݀͗׵̾ʊáLJѪ
ٹȭםޮɅ֜ʼݥޤڎۊ΂ŭЁ˹īʶñۼ[׈ӽه:3ŜSԛģó͑؝Јי̅ݏˬˮіۍ
PԅM׷ѯԶɔܺ֘ݷԾڽˎΞn̏ŗۧ˒ޥϷDžŀ˳Ѡ̮ݕũۃɹƾފѼܚٍڢŽܛńի
߀CžʾʹքӭξҖҢǘZ<ɼÐՅ̔ݧئ٫ʖѬ̩ߌǿɇݻ÷ђΤǀёՓJѦϻΥ¨̦ڥ
ˍ͖٭зݡѧס̶̵¯ȐƌޭԮϙҦ+ڦÇ֍ɽƥЦ۩ǦҠêʧɮð̣̯ޘƭƠͺޠ׺ݩγ
ѳ֊НۜÚӺϭ̃ݵƬŇЎٛԪճɟЩЋֱϜޒfޓʨ؄ܮɱղŬέǏu։Ҹ˅رɾʘ׶ͅ
߃¾ª"ɖȾύƔýՈԉգȨڼۮ͍õŘ]àߊܱЫҴٗԞۢ ˂ہƞ׻ɺƚ۞ҤڻƸǵǯ
܄ʠƲťïܠmТϋɥΈώͶ٢ؖټ\Ŵˣé֔ڤÿϛσ߂Λøʞӿăմ؉ϪЗպƓ҆܀ݰ
ѹΏɨғڲƀɞԗ26Ĕŵ³ѥ͛ǨՄǓĻ֌ڊʝӹʍ̠ϰ͸ʄՍə܅лġޏnj˴ʃ۵Ϻdž
՟Ҽ̈۹ԺߎМރѵ͋ؾЇѐ|ԨةݝɕǕڴljȩþؐ؆׉j˿ق۽ɳОѷęijٯÂě޳ȴ
˓חګ٠ޅךćءɉӢɗчЉő͜Ѐ֨ےϸܽԀ»эјۇޣ֤Ґ͊ȫއɒۓ۷́ضӖΙَБ
×ʳҧЅȗUƅŷÈɸȕ܆ĵޖȁɢӼԒѢխǖ@ǡȰ՘޵ўҍГӛº۾ף˔ъͣʏ«ћڏ
حǟΖԕƑǼթٸe֦ʗސڍƙКԻ̿ιü̧´փϱʤܭηƷѨЮԭѿ¢ßݚؒ٪ҩʢں`
۠μưɍӉØN̬ވƘȈ֎ǝٙӷΨи¥՗еοݫ̷Ɨ?ͰĹ֝ݸ_؇Àׁ̌ûʥĭȶǍԔ
үơ̕ג׸˗ϑӤ׼Ӱ'άܶѮĀشڱӻǻܼƿ܉ͪ޽Ѱܑ̓K~Ұ֮πҬʷ˫ۯٿpВ̥
տؓЍܒ˲ӥɰާڜԫ͎ϿűӈϦƤڣʓƎѱޛяâޱƻЄÃ̸ـ̂֕Ӛ̗֣ͬӦ݄ۑƦܖ
߄ɷۉڨȑձІȖƯٵۡуħۦِ̱ԢɑФ׾١̺دʂsչ.ۋҾėè˭ٷbϮݱݔǩʈ
ȻiͫϯԦĚػţ܍׭եֿχ޺݂ت܁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[edit]

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.

$ 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;

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[edit]

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
Output:
"\ba\0b\n\rc\fd\xC3\x7Ffoo"
"abcd\xC3foo"
"abcdfoo"

Tcl[edit]

proc stripAsciiCC str {
regsub -all {[\u0000-\u001f\u007f]+} $str ""
}
proc stripCC str {
regsub -all {[^\u0020-\u007e]+} $str ""
}

TI-83 BASIC[edit]

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:

#$&@;_`abcdefghijklmnopqrstuvwxyz|~

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.

:" !#$%&'()*+,-./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

TXR[edit]

Translation of: Racket
(defun strip-controls (str)
(regsub #/[\x0-\x1F\x7F]+/ "" str))
 
(defun strip-controls-and-extended (str)
(regsub #/[^\x20-\x7F]+/ "" str))

VBScript[edit]

Derived from the BASIC version.

 
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
 
Output:
ab�cd�ef�gh?€ = abcdefgh€
ab�cd�ef�gh?ij†klð€ = abcdefghijkl

XPL0[edit]

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);
]

Output:

Hello
 World àáâã
Hello World àáâã
Hello World 

zkl[edit]

ASCII

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");
 
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