chr

Note that if the number is higher than 256, it will return the number mod 256.For example :chr(321)=A because A=65(256)

Another quick and short function to get unicode char by its code.<?php/** * Return unicode char by its code * * @param int $u * @return char */function unichr($u) {    return mb_convert_encoding('&#' . intval($u) . ';', 'UTF-8', 'HTML-ENTITIES');}?>

I spent hours looking for a function which would take a numeric HTML entity value and output the appropriate UTF-8 bytes.  I found this at another site and only had to modify it slightly; so I don't take credit for this.<?php function unichr($dec) {   if ($dec < 128) {     $utf = chr($dec);   } else if ($dec < 2048) {     $utf = chr(192 + (($dec - ($dec % 64)) / 64));     $utf .= chr(128 + ($dec % 64));   } else {     $utf = chr(224 + (($dec - ($dec % 4096)) / 4096));     $utf .= chr(128 + ((($dec % 4096) - ($dec % 64)) / 64));     $utf .= chr(128 + ($dec % 64));   }   return $utf;} ?>So for example:<?php  $str = "Chinese: &#20013;&#25991;";  $str = preg_replace("/&#(\d{2,5});/e", "unichr($1);", $str);?>

Here is a sample of encoding and decoding using "chr" and "ord".<?php    function Encode($txtData,$Level){        for ($j = 0;$j<$Level;$j++){            $tmpStr = '';            for ($i = 0;$i<strlen($txtData);$i++)                $tmpStr .= ord(substr(strtoupper($txtData), $i, 1));            $txtData = $tmpStr;        }        return (strlen($Level)).$Level.$txtData;    }    function Decode($txtData){        $intLevel = substr($txtData, 1, substr($txtData, 0, 1));        $startStr = substr($txtData, substr($txtData, 0, 1)+1, strlen($txtData));        for ($j = 0;$j<$intLevel;$j++){            for ($i = 0;$i<strlen($startStr);$i+=2)                $tmpStr .= chr(intval(substr($startStr, $i, 2)));            $startStr = $tmpStr;                    $tmpStr = "";        }        return $startStr;    }echo Encode('123',4).'<br>';echo Decode(Encode('123',5));?>

<?phpfor ($i = 128; $i <= 191; $i++) {    $str = chr(240) . chr(159) . chr(144) . chr($i);    echo $str;}?>

// rivencodec 1.0// encode riverse ascii 1 simple function can encode/decode // can use it for secure source with speed encode text<?php    function rivencodec($ch,$a=0) {        while((@$b = $ch[$a++])) { $ch[$a-1] = chr(255-ord($b)); }        return $ch;    }            $zz = rivencodec("abcdefghijklmn");echo 'encode: ',$zz,'<br/>',PHP_EOL;$yy = rivencodec($zz);echo 'decode: ',$yy,'<br/>',PHP_EOL;?>

Want terminal colors in command line php scripts?

This should take care of that.
<?

$_colors = array(
        'LIGHT_RED'      => "[1;31m",
        'LIGHT_GREEN'     => "[1;32m",
        'YELLOW'     => "[1;33m",
        'LIGHT_BLUE'     => "[1;34m",
        'MAGENTA'     => "[1;35m",
        'LIGHT_CYAN'     => "[1;36m",
        'WHITE'     => "[1;37m",
        'NORMAL'     => "[0m",
        'BLACK'     => "[0;30m",
        'RED'         => "[0;31m",
        'GREEN'     => "[0;32m",
        'BROWN'     => "[0;33m",
        'BLUE'         => "[0;34m",
        'CYAN'         => "[0;36m",
        'BOLD'         => "[1m",
        'UNDERSCORE'     => "[4m",
        'REVERSE'     => "[7m",

);

function termcolored($text, $color="NORMAL", $back=1){
    global $_colors;
    $out = $_colors["$color"];
    if($out == ""){ $out = "[0m"; }
    if($back){
        return chr(27)."$out$text".chr(27).chr(27)."[0m".chr(27);
    }else{
        echo chr(27)."$out$text".chr(27).chr(27)."[0m".chr(27);
    }//fi
}// end function

echo termcolored("test\n", "BLUE");
?>

to remove the ASCII control characters (except "line feed" and "tab") :$tab_chr = array() ;for($control = 0; $control < 32; $control++) {    if ($control != 9 && $control != 10) {        $tab_chr[]= chr($control) ;    }}$tab_chr[]= chr(127) ;    $string = str_replace($tab_chr, '', $string);

When having to deal with parsing an IIS4 or IIS5 metabase dump I wrote a simple function for converting those MS hexidecimal values into their ascii counter parts. Hopefully someone will find use for it.

<?php
function hex_decode($string)  {
        for ($i=0; $i < strlen($string); $i)  {
        $decoded .= chr(hexdec(substr($string,$i,2)));
        $i = (float)($i)+2;
        }
return $decoded;
}
?>

In addition to replacing Microsoft Windows smart quotes, as sgaston demonstrated on 2006-02-13, I replace all other Microsoft Windows characters using suggestions[1] published by character code specialist[2] Jukka Korpela.<?php$str = str_replace(chr(130), ',', $str);    // baseline single quote$str = str_replace(chr(131), 'NLG', $str);  // florin$str = str_replace(chr(132), '"', $str);    // baseline double quote$str = str_replace(chr(133), '...', $str);  // ellipsis$str = str_replace(chr(134), '**', $str);   // dagger (a second footnote)$str = str_replace(chr(135), '***', $str);  // double dagger (a third footnote)$str = str_replace(chr(136), '^', $str);    // circumflex accent$str = str_replace(chr(137), 'o/oo', $str); // permile$str = str_replace(chr(138), 'Sh', $str);   // S Hacek$str = str_replace(chr(139), '<', $str);    // left single guillemet$str = str_replace(chr(140), 'OE', $str);   // OE ligature$str = str_replace(chr(145), "'", $str);    // left single quote$str = str_replace(chr(146), "'", $str);    // right single quote$str = str_replace(chr(147), '"', $str);    // left double quote$str = str_replace(chr(148), '"', $str);    // right double quote$str = str_replace(chr(149), '-', $str);    // bullet$str = str_replace(chr(150), '-', $str);    // endash$str = str_replace(chr(151), '--', $str);   // emdash$str = str_replace(chr(152), '~', $str);    // tilde accent$str = str_replace(chr(153), '(TM)', $str); // trademark ligature$str = str_replace(chr(154), 'sh', $str);   // s Hacek$str = str_replace(chr(155), '>', $str);    // right single guillemet$str = str_replace(chr(156), 'oe', $str);   // oe ligature$str = str_replace(chr(159), 'Y', $str);    // Y Dieresis?>[1] On the use of some MS Windows characters in HTMLhttp://www.cs.tut.fi/~jkorpela/www/windows-chars.html[2] Unicode Explained by Jukka Korpela http://www.amazon.com/dp/059610121X/

Secure password generator with a variable maximum amount of symbols.<?phpfunction passwdGen($minLength = 8, $maxLength = 12, $maxSymbols = 2){    $symbolCount = 0;    srand((double)microtime() * 1000003);    for ($i = 0; $i < rand($minLength, $maxLength); $i++)    {        do        {            $char = rand(33, 126);            $symbolCount += $isSymbol = (!in_array($char, range(48, 57)) && !in_array($char, range(65, 90)) && !in_array($char, range(97, 122)));            if ($symbolCount <= $maxSymbols || !$isSymbol)            {                break;            }        }        while (true);        $passwd = sprintf('%s%c', isset($passwd) ? $passwd : NULL, $char);    }    return $passwd;}?>

Here is a function that's help me find what chr(number) outputs what character quicker than typing out 256 echo tags.

<?php
 function listChr(){
  for ($i = 0; $i < 256; ++$i) {
  static $genNum;
  $genNum++;
  echo "chr($genNum) will output '";
  echo (chr($genNum));
  echo "'< br>\n";
  }
}
listChr();
?>

Another helpful chr is #9, being a tab.  Quite using when making error logs.

 $tab = (chr(9));
 echo "<pre>error{$tab}date{$tab}time</pre>";

 -- HappyEvil

I needed to generate an invalid UTF-8 character for testing with JSON.  This did the trick:<?phpecho 'Bogus UTF-8 character at end' . chr(0xC6) ;

Another quick function to get unicode char by its code.<?phpfunction unichr($dec){  if ($dec < 0x80)  {    $utf = chr($dec);  }  else if ($dec < 0x0800)  {    $utf = chr(0xC0 + ($dec >> 6));    $utf .= chr(0x80 + ($dec & 0x3f));  }  else if ($dec < 0x010000)  {    $utf = chr(0xE0 + ($dec >> 12));    $utf .= chr(0x80 + (($dec >> 6) & 0x3f));    $utf .= chr(0x80 + ($dec & 0x3f));  }  else if ($dec < 0x200000)  {    $utf = chr(0xF0 + ($dec >> 18));    $utf .= chr(0x80 + (($dec >> 12) & 0x3f));    $utf .= chr(0x80 + (($dec >> 6) & 0x3f));    $utf .= chr(0x80 + ($dec & 0x3f));  }  else  {    die("UTF-8 character size is more than 4 bytes");  }  return $utf;}echo unichr(0x263A);?>

Simple password generation function using sprintf and the %c type specifier; which is the same as chr().function genPass($len = 8) {    for ($i=0;$i<=$len;$i++) {        $passwd = sprintf('%s%c', isset($passwd) ? $passwd : NULL, rand(48, 122));    }    return $passwd;}

[Editor's note:

%c is defined as: "Print the character belonging to the ascii code given"

chr() just gives a string, so you need to use %s, even if the string consists of only one character. This is consistent with other languages.
--Jeroen@php.net]


Learn from my mistake:
Do not expect this to work!

<?php
$c_question = chr(63);
$v_out = sprintf("<%cphp\n", $c_question);
//... more stuff being sprintf'd into v_out here ...
$v_out = sprintf("%s%c>\n", $v_out, $c_question);
$v_fp = fopen("foofile", "w");
if ($v_fp)
{
     fwrite($v_fp, $v_out, strlen($v_out));
     fclose($v_fp);
}
?>

When I did this, foofile contained <NUL NUL NUL NUL NUL>.
I spun my wheels quite awhile looking at fputs, fwrite to verify I was calling those functions correctly.
My mistake was using $c_question = chr(63) instead of
$c_question = 63 (correct).  Then everything worked fine.

Note that chr(10) is a 'line feed' and chr(13) is a 'carriage return' and they are not the same thing! I found this out while attempting to parse text from forms and text files for inclusion as HTML by replacing all the carriage returns with <BR>'s only to find after many head-scratchings that I should have been looking for line feeds. If anyone can shed some light on what the difference is, please do.

If you're planning on saving text from a form into a database for later display, you'll need to apply the following function so that it gets saved with the proper HTML tags.

<?php
$text = str_replace ( chr(10), "<BR>", $text );
?>

When you want to plug it back into that form for editing you need to convert it back.

<?php
$text = str_replace ( "<BR>", chr(10), $text)
?>

Hope this saves somebody some trouble. :)

argument is automatically converted to integer, so chr('65') and chr(65) would both output the letter A

string mb_chr ( int $cp [, string $encoding ] )Parameter List:cp - character code (in decimal notation)encoding - encoding (UTF-8, ASCII and so on)We get the letter 'Ж'  from the encoding UTF-8:$sim = mb_chr(0x0416, 'UTF-8');echo $sim; // ЖGet the character '}' from the encoding ASCII:$sim = mb_chr(125, 'ASCII');echo $sim ; // }

It seems that php uses the table from here: http://ascii-code.com/ (and not from here: http://www.asciitable.com/ as suggested in the documentation) for codes from 128 to 255.<?phpfor ($i = 32; $i <= 255; $i++) {    echo chr($i);}?>

chr() with unicode support<?phpfunction uchr ($codes) {    if (is_scalar($codes)) $codes= func_get_args();    $str= '';    foreach ($codes as $code) $str.= html_entity_decode('&#'.$code.';',ENT_NOQUOTES,'UTF-8');    return $str;}echo uchr(23383); echo '<br/>';echo uchr(23383,215,23383); echo '<br/>';echo uchr(array(23383,215,23383,215,23383)); echo '<br/>';?>

I was looking for a simple method to construct excel like column identifiers e.g: A B .... AA AB AC etc, using chr() and modulo, but there is magic...https://www.php.net/manual/en/language.operators.increment.phpSo, this also works<?php$p = chr(65);      // or simply $p = 'A';for ($i = 1; $i < 53; $i++){    echo $p++ . " - ";    if ($i % 10 == 0) echo '</br>';}?>GivesA - B - C - D - E - F - G - H - I - J -K - L - M - N - O - P - Q - R - S - T -U - V - W - X - Y - Z - AA - AB - AC - AD -AE - AF - AG - AH - AI - AJ - AK - AL - AM - AN -AO - AP - AQ - AR - AS - AT - AU - AV - AW - AX -AY - AZ -

The function chr() also accepts negative numbers as an ascii code, so chr(-number) is equal to chr((number%256)+256).
And for ascii code higher than 255 is chr(number%256)

We can test with a little script
<?php
    for($i=-300; $i<300; $i++){
        echo "Ascii $i\t" . ord(chr($i)) . "\n";
    }
?>