字符串函数
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chr

(PHP 4, PHP 5)

chr — 返回指定的字符

说明

string chr ( int $ascii )

返回相对应于 ascii 所指定的单个字符。

Example #1 chr() 例子

<?php
$str = "The string ends in escape: ";
$str .= chr(27); /* 在 $str 后边增加换码符 */

/* 通常这样更有用 */

$str = sprintf("The string ends in escape: %c", 27);
?>

可以在此处找到 ASCII 码表：» http://www.asciitable.com。

此函数与 ord() 是互补的。参见 sprintf() 如何使用格式字符串 %c。

参数

ascii

The ascii code.

返回值

Returns the specified character.

范例

Example #2 chr() example

<?php
$str = "The string ends in escape: ";
$str .= chr(27); /* add an escape character at the end of $str */

/* Often this is more useful */

$str = sprintf("The string ends in escape: %c", 27);
?>

参见

字符串函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 返回指定的字符

用户评论:

gjarrige at six-axe dot fr (01-Mar-2012 05:47)

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);

stanislav at nechutny dot net (01-Oct-2011 02:26)

There is simple function for converting number to chars. If you want make table like excel where colums are indetified by chars A,B,C...AA,AB.. you can easyli iterate on integer and call this function.
<?php
function numtochars($num,$start=65,$end=90)
{
    $sig = ($num < 0);
    $num = abs($num);
    $str = "";
    $cache = ($end-$start);
    while($num != 0)
    {
        $str = chr(($num%$cache)+$start-1).$str;
        $num = ($num-($num%$cache))/$cache;
    }
    if($sig)
    {
        $str = "-".$str;
    }
    return $str;
}
?>

robin leffmann (24-Sep-2011 04:46)

While the documentation appears to imply ASCII character operation only, chr() can actually be used to convert arbitrary byte values into binary content:

<?php

while( @$i++ < 32 )
    $a = chr( mt_rand(0, 255) );

file_put_contents( 'filename', $a );

?>

mailderemi at gmail dot com (04-Feb-2011 04:17)

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));
?>

Icar (11-Mar-2010 04:31)

Here is code for generation Russian alphabet:
<?php
for ($i=176;$i<=207;++$i) {
    echo $i.'='.iconv('ISO-8859-5', 'UTF-8', chr($i)).'<br>';
}
?>
This simple code generates all Russian capital letters, but without 'Ё'.

Emprivo.com (01-Sep-2009 03:36)

Replaces special characters with non-special equivalents

<?php
function normalize_special_characters( $str )
{
    # Quotes cleanup
    $str = ereg_replace( chr(ord("`")), "'", $str );        # `
    $str = ereg_replace( chr(ord("?")), "'", $str );        # ?
    $str = ereg_replace( chr(ord("?")), ",", $str );        # ?
    $str = ereg_replace( chr(ord("`")), "'", $str );        # `
    $str = ereg_replace( chr(ord("?")), "'", $str );        # ?
    $str = ereg_replace( chr(ord("“")), "\"", $str );        # “
    $str = ereg_replace( chr(ord("”")), "\"", $str );        # ”
    $str = ereg_replace( chr(ord("?")), "'", $str );        # ?

    $unwanted_array = array(    '?'=>'S', '?'=>'s', '?'=>'Z', '?'=>'z', '?'=>'A', '?'=>'A', '?'=>'A', '?'=>'A', '?'=>'A', '?'=>'A', '?'=>'A', '?'=>'C', '?'=>'E', '?'=>'E',
                                '?'=>'E', '?'=>'E', '?'=>'I', '?'=>'I', '?'=>'I', '?'=>'I', '?'=>'N', '?'=>'O', '?'=>'O', '?'=>'O', '?'=>'O', '?'=>'O', '?'=>'O', '?'=>'U',
                                '?'=>'U', '?'=>'U', '?'=>'U', '?'=>'Y', '?'=>'B', '?'=>'Ss', 'à'=>'a', 'á'=>'a', '?'=>'a', '?'=>'a', '?'=>'a', '?'=>'a', '?'=>'a', '?'=>'c',
                                'è'=>'e', 'é'=>'e', 'ê'=>'e', '?'=>'e', 'ì'=>'i', 'í'=>'i', '?'=>'i', '?'=>'i', '?'=>'o', '?'=>'n', 'ò'=>'o', 'ó'=>'o', '?'=>'o', '?'=>'o',
                                '?'=>'o', '?'=>'o', 'ù'=>'u', 'ú'=>'u', '?'=>'u', '?'=>'y', '?'=>'y', '?'=>'b', '?'=>'y' );
    $str = strtr( $str, $unwanted_array );

    # Bullets, dashes, and trademarks
    $str = ereg_replace( chr(149), "&#8226;", $str );    # bullet ?
    $str = ereg_replace( chr(150), "&ndash;", $str );    # en dash
    $str = ereg_replace( chr(151), "&mdash;", $str );    # em dash
    $str = ereg_replace( chr(153), "&#8482;", $str );    # trademark
    $str = ereg_replace( chr(169), "&copy;", $str );    # copyright mark
    $str = ereg_replace( chr(174), "&reg;", $str );        # registration mark

    return $str;
}
?>

sinfocol at sinfocol dot org (30-Jun-2009 10:38)

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";
    }
?>

glen at glencooper dot com (10-Mar-2009 07:27)

Thank you joeldegan for your termcolored function.  I write a lot of command-line scripts using PHP and like to colorize them.  I was having a problem with the termcolored function where the next character echo'ed after calling termcolored() was being dropped.  Turns out you don't need the extra chr(27) at the end of each term color code.

Here's my modified version of your function, renamed to echocolor.

<?php
function echocolor($text,$color="normal",$back=0)
{
  $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" );
  $out = $colors["$color"];
  $ech = chr(27)."$out"."$text".chr(27)."[0m";
  if($back)
  {
    return $ech;
  }
  else
  {
    echo $ech;
  }
}
?>

voromax (31-Jan-2009 03:39)

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');
}
?>

jacob at loggy punt nl (31-Dec-2008 01:46)

This function creates a ascii table, and replaces all the ascii characters in the mail.
---
Deze functie maakt een ascii tabel, en zet alles juist om.

<?php
 function makeASCII($a){
  $find[] = "=\r\n";
  $replace[] = "";
 
  for($i=0; $i < 256; $i++){
    $find[] = "=".dechex($i)."";
    $replace[] = chr($i);
  }
  $a = str_replace($find,$replace,$a);
  return $a;
 }
?>

scott at quinlan dot co dot nz (21-Oct-2008 05:51)

Secure password generator with a variable maximum amount of symbols.

<?php

function 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;
}

?>

Josh B. (12-Aug-2008 10:06)

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 HTML
http://www.cs.tut.fi/~jkorpela/www/windows-chars.html

[2] Unicode Explained by Jukka Korpela
http://www.amazon.com/dp/059610121X/

markem at airmail dot net (09-Jul-2008 11:34)

First, the linefeed versus carriage return confusion:

When typewriters were first invented they were manually moved.  You could do a couple of things with them.  You could type on it (which would move the carriage one space to the left as you typed each character), you could hit the backspace key (which would move the carriage one space to the right), press the line feed button (which would cause the carriage to roll up one line), and return (which would move the carriage all the way to the right again).  When electric typewriters came in to being these functions were made into their electronic counterparts. When terminals appeared they were given the same functions just as word processors, text editors, and everything else that deals with the typed word handles them.

When computers first came out though, the dopey people who invented them wanted to distinguish themselves.  One of the ways they did that was to only use some of the commands.  Which is why the Macintosh originally only used the carriage return command and why Linux/Unix only used the line feed command.  This is why there is "\r" (carriage return), "\l" (Line Feed), and "\n" (OS appropriate).  One of the few things that IBM got right was that it should really be <Carriage Return><Line Feed> and not just one or the other.

So like the reason our roads are a certain width is because that was the width of two horses pulling a Roman chariot, the reason we use these terms is because of the humble non-electronic typewriter and how it worked.

Second - I believe that PHP actually generates ANSI characters and not ASCII characters.  Although there were different extended character sets for the ASCII characters (ie: 128-255), the one depicted on the http://www.asciitable.com/ website clearly shows the IBM standardized ASCII extended table.  (ie: If you ran a BASIC program on your computer you would see the set shown on the above website.)  If, however, you print out the characters via the CHR() function in PHP it prints out the ANSI character set.  (ASCII and ANSI are the same for 0-127.)  Although you can get the characters to print (via Unicode) through the CHR() function - this is still simply showing it is using ANSI and not ASCII.  (Because Unicode is an extension of the ANSI character set and not the ASCII character set.)

If this is so (and my tests show it is) - should the documentation be changed to reflect this?  :-?

darkodemon at gmail dot com (27-Apr-2007 12:33)

chr() with unicode support

<?php

function 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/>';

?>

mwgamera at gmail dot com (22-Aug-2006 04:20)

Unicode version of chr() using mbstring
<?php
  function unichr($u) {
    return mb_convert_encoding(pack("N",$u), mb_internal_encoding(), 'UCS-4BE');
  }
?>
It returns a string in internal encoding (possibly more than one byte).

JasonLauDotBiz (17-Feb-2006 03:34)

I didn't see it here, so here's simple random string generation using char.

<?php
for($i=0; $i<7; $i++){
    $random_string .= chr(rand(0,25)+65);
}
echo $random_string;
?>

sgaston at mercy corps dot ()rg (13-Feb-2006 10:52)

I found this function useful as a way to detect and to replace Microsoft Smart Quotes when desplaying info on a webpage.

The following lines seem to do the trick:

<?php
$text = "string containing Microsoft Smart Quotes...";
$chrs = array (chr(150), chr(147), chr(148), chr(146));
$repl = array ("-", "\"", "\"", "'");
$text = str_replace($chrs, $repl, $text);
?>

plugwash at p10link dot net (14-Jan-2006 08:41)

bear in mind that php doesn't really care about character sets. php strings are just arbitary byte sequences thier meaning (especailly when you go beyond code 127) depends entirely on whats interpreting the data (in the case of a browser the charset specified in the http headers).

admin at icstrategy dot midgetforhire dot com (08-Jan-2006 06:51)

I made a password generator with this function...

<?php
$passlength = 8;
$pass = "";
$i = 0;
while($i <= $passlength)
    {
    $pass .= chr(rand(33,126));
    $i++;
    }
echo $pass;
?>

Ofcourse you can change passlength.

Example of an 8-char password:
AFJ\)t'u}

I realise it isn't compatible for all sites, but most will accept :)

grey - greywyvern - com (19-Aug-2005 03:55)

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);

?>

(24-May-2005 03:15)

If you want to increment your letter, which is stored as a string, you have to convert it back to an integer first.

<?php
    $letter=strtolower($_GET['letter']);    //You wanted this originally, but not decided you want the previous letter
    $letter=ord($letter);            //Convert to an integer
    $letter=chr($letter-1);            //Convert back to a string, but the previous letter (naturally won't work with A or a)
?>

sarabas at itstudio dot pl (17-Feb-2005 12:26)

The following function helped me to generate ascii-only usernames from firstname/lastname containing iso-8859-2 characters. The convertion array was based on contents of 'man iso-8859-2'.

Example: iso2ascii("b&#322;a&#380;ej.&#378;d&#378;b&#322;o") returns "blazej.zdzblo"

<?php
function iso2ascii($str) {
 $arr=array(
  chr(161)=>'A', chr(163)=>'L', chr(165)=>'L', chr(166)=>'S', chr(169)=>'S',
  chr(170)=>'S', chr(171)=>'T', chr(172)=>'Z', chr(174)=>'Z', chr(175)=>'Z',
  chr(177)=>'a', chr(179)=>'l', chr(181)=>'l', chr(182)=>'s', chr(185)=>'s',
  chr(186)=>'s', chr(187)=>'t', chr(188)=>'z', chr(190)=>'z', chr(191)=>'z',
  chr(192)=>'R', chr(193)=>'A', chr(194)=>'A', chr(195)=>'A', chr(196)=>'A',
  chr(197)=>'L', chr(198)=>'C', chr(199)=>'C', chr(200)=>'C', chr(201)=>'E',
  chr(202)=>'E', chr(203)=>'E', chr(204)=>'E', chr(205)=>'I', chr(206)=>'I',
  chr(207)=>'D', chr(208)=>'D', chr(209)=>'N', chr(210)=>'N', chr(211)=>'O',
  chr(212)=>'O', chr(213)=>'O', chr(214)=>'O', chr(216)=>'R', chr(217)=>'U',
  chr(218)=>'U', chr(219)=>'U', chr(220)=>'U', chr(221)=>'Y', chr(222)=>'T',
  chr(223)=>'s', chr(224)=>'r', chr(225)=>'a', chr(226)=>'a', chr(227)=>'a',
  chr(228)=>'a', chr(229)=>'l', chr(230)=>'c', chr(231)=>'c', chr(232)=>'c',
  chr(233)=>'e', chr(234)=>'e', chr(235)=>'e', chr(236)=>'e', chr(237)=>'i',
  chr(238)=>'i', chr(239)=>'d', chr(240)=>'d', chr(241)=>'n', chr(242)=>'n',
  chr(243)=>'o', chr(244)=>'o', chr(245)=>'o', chr(246)=>'o', chr(248)=>'r',
  chr(249)=>'u', chr(250)=>'u', chr(251)=>'u', chr(252)=>'u', chr(253)=>'y',
  chr(254)=>'t'
 );
 return strtr($str,$arr);
}
?>

tenyou at gmail dot com (15-Jul-2004 07:05)

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;
}
?>

jmartin at prescientsoftware dot com (13-Apr-2004 10:42)

Here is a function that will convert column numbers in to a letters for use in a spreadsheet.  It is limited up to 'ZZ' but can easliy by modifed.

<?php
 function col2chr($a){
        if($a<27){
            return strtoupper(chr($a+96));   
        }else{
            while($a > 26){
                $b++;
                $a = $a-26;               
            }                  
            $b = strtoupper(chr($b+96));   
            $a = strtoupper(chr($a+96));               
            return $b.$a;
        }
    }
?>

perrodin at laposte dot net (12-Apr-2004 12:20)

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)

jgray at triangle dash solutions dot com (25-Jul-2003 06:20)

Lowercase alphabet:
<?php for($a=97;$a<(97+26);$a++){ echo chr($a); } ?>

infoserv at chollian dot net (25-Jun-2003 04:16)

Cutting Korean(2Byte)-String

<?php
function cutStr($str,$len){
    if(strlen($str) > $len){
        $str = substr($str,0,$len - 2);
        if(strlen(substr(strrchr($str," "),1)) % 2)
            $str = substr($str,0,strlen($str) - 1);
        $str .= "..";
    }
    return $str;
}
?>

jcokos (27-Mar-2003 02:12)

A quick function that I use to make strings "XML" compliant, changing every special character into their #$... equivalent.

htmlentities doesn't get all of the chars above 127, so the second part of this (which I stole from one of the comments above) finishes the process, returning a nice, xml happy string.

<?php
    function strictify ( $string ) {

        $fixed = htmlentities( $string, ENT_QUOTES );

        $trans_array = array();
        for ($i=127; $i<255; $i++) {
           $trans_array[chr($i)] = "&#" . $i . ";";
        }

        $really_fixed = strtr($fixed, $trans_array);

        return $really_fixed;

    }
?>

HTH

Kristin (07-Mar-2003 04:19)

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. :)

joeldegan AT yahoo.com (14-Dec-2002 10:53)

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");
?>

gschafer at robandger dot com (09-Nov-2002 12:17)

Here's a small function I wrote up to generate random passwords using the chr() function.

<?php
function randPass($len)
{
 $pw = ''; //intialize to be blank
 for($i=0;$i<$len;$i++)
 {
   switch(rand(1,3))
   {
     case 1: $pw.=chr(rand(48,57));  break; //0-9
     case 2: $pw.=chr(rand(65,90));  break; //A-Z
     case 3: $pw.=chr(rand(97,122)); break; //a-z
   }
 }
 return $pw;
}
?>

Example:

<?php
 $password = randPass(10); //assigns 10-character password
?>

I found this useful in my early coding days... I'm sure someone else will too :D

(29-Jun-2002 04:05)

This bit of code will convert all those lovely tilde,umlaut etc. etc. characters into safe character codes:

<?php
    $trans_array = array();
    for ($i=127; $i<255; $i++) {
        $trans_array[chr($i)] = "&#" . $i . ";";
    }
    $outtext = strtr($intext, $trans_array);
?>

webmaster at project-enigma dot net (13-Apr-2002 08:51)

\n == &#13;
Usefull if u want to display multi-line-alt-strings
e.g. <img src="/gifs/php_logo.gif" alt="Here u can see the&#13;PHPLogo&#13;3rd line">

happyevil(at)1218.org (27-Mar-2001 03:31)

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

ddawsonNOSPAM at execpc dot com (10-May-2000 12:59)

[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.