strtr

(PHP 4, PHP 5, PHP 7)

strtr — Translate characters or replace substrings

Description

string strtr ( string $str , string $from , string $to )

string strtr ( string $str , array $replace_pairs )

If given three arguments, this function returns a copy of str where all occurrences of each (single-byte) character in from have been translated to the corresponding character in to, i.e., every occurrence of $from[$n] has been replaced with $to[$n], where $n is a valid offset in both arguments.

If from and to have different lengths, the extra characters in the longer of the two are ignored. The length of str will be the same as the return value's.

If given two arguments, the second should be an array in the form array('from' => 'to', ...). The return value is a string where all the occurrences of the array keys have been replaced by the corresponding values. The longest keys will be tried first. Once a substring has been replaced, its new value will not be searched again.

In this case, the keys and the values may have any length, provided that there is no empty key; additionally, the length of the return value may differ from that of str. However, this function will be the most efficient when all the keys have the same size.

Parameters

str: The string being translated.
from: The string being translated to to.
to: The string replacing from.
replace_pairs: The replace_pairs parameter may be used instead of to and from, in which case it's an array in the form array('from' => 'to', ...).

Return Values

Returns the translated string.

If replace_pairs contains a key which is an empty string (""), FALSE will be returned. If the str is not a scalar then it is not typecasted into a string, instead a warning is raised and NULL is returned.

Examples

Example #1 strtr() example


<?php
//In this form, strtr() does byte-by-byte translation
//Therefore, we are assuming a single-byte encoding here:
$addr = strtr($addr, "äåö", "aao");
?>

The next example shows the behavior of strtr() when called with only two arguments. Note the preference of the replacements ("h" is not picked because there are longer matches) and how replaced text was not searched again.

Example #2 strtr() example with two arguments


<?php
$trans = array("h" => "-", "hello" => "hi", "hi" => "hello");
echo strtr("hi all, I said hello", $trans);
?>

The above example will output:

hello all, I said hi

The two modes of behavior are substantially different. With three arguments, strtr() will replace bytes; with two, it may replace longer substrings.

Example #3 strtr() behavior comparison


<?php
echo strtr("baab", "ab", "01"),"\n";

$trans = array("ab" => "01");
echo strtr("baab", $trans);
?>

The above example will output:

1001
ba01

User Contributed Notes

evan dot king at NOSPAM dot example dot com

1 year ago


Here's an important real-world example use-case for strtr where str_replace will not work or will introduce obscure bugs:

<?php

$strTemplate = "My name is :name, not :name2.";
$strParams = [
  ':name' => 'Dave',
  'Dave' => ':name2 or :password', // a wrench in the otherwise sensible input
  ':name2' => 'Steve',
  ':pass' => '7hf2348', // sensitive data that maybe shouldn't be here
];

echo strtr($strTemplate, $strParams);
// "My name is Dave, not Steve."

echo str_replace(array_keys($strParams), array_values($strParams), $strTemplate);
// "My name is Steve or 7hf2348word, not Steve or 7hf2348word2."

?>

Any time you're trying to template out a string and don't necessarily know what the replacement keys/values will be (or fully understand the implications of and control their content and order), str_replace will introduce the potential to incorrectly match your keys because it does not expand the longest keys first.

Further, str_replace will replace in previous replacements, introducing potential for unintended nested expansions.  Doing so can put the wrong data into the "sub-template" or even give users a chance to provide input that exposes data (if they get to define some of the replacement strings).

Don't support recursive expansion unless you need it and know it will be safe.  When you do support it, do so explicitly by repeating strtr calls until no more expansions are occurring or a sane iteration limit is reached, so that the results never implicitly depend on order of your replacement keys.  Also make certain that any user input will expanded in an isolated step after any sensitive data is already expanded into the output and no longer available as input.

Note: using some character(s) around your keys to designate them also reduces the possibility of unintended mangling of output, whether maliciously triggered or otherwise.  Thus the use of a colon prefix in these examples, which you can easily enforce when accepting replacement input to your templating/translation system.

dot dot dot dot dot alexander at gmail dot com

8 years ago


OK, I debugged the function (had some errors)
Here it is:

if(!function_exists("stritr")){
    function stritr($string, $one = NULL, $two = NULL){
/*
stritr - case insensitive version of strtr
Author: Alexander Peev
Posted in PHP.NET
*/
        if(  is_string( $one )  ){
            $two = strval( $two );
            $one = substr(  $one, 0, min( strlen($one), strlen($two) )  );
            $two = substr(  $two, 0, min( strlen($one), strlen($two) )  );
            $product = strtr(  $string, ( strtoupper($one) . strtolower($one) ), ( $two . $two )  );
            return $product;
        }
        else if(  is_array( $one )  ){
            $pos1 = 0;
            $product = $string;
            while(  count( $one ) > 0  ){
                $positions = array();
                foreach(  $one as $from => $to  ){
                    if(   (  $pos2 = stripos( $product, $from, $pos1 )  ) === FALSE   ){
                        unset(  $one[ $from ]  );
                    }
                    else{
                        $positions[ $from ] = $pos2;
                    }
                }
                if(  count( $one ) <= 0  )break;
                $winner = min( $positions );
                $key = array_search(  $winner, $positions  );
                $product = (   substr(  $product, 0, $winner  ) . $one[$key] . substr(  $product, ( $winner + strlen($key) )  )   );
                $pos1 = (  $winner + strlen( $one[$key] )  );
            }
            return $product;
        }
        else{
            return $string;
        }
    }/* endfunction stritr */
}/* endfunction exists stritr */

Hayley Watson

3 years ago


Since strtr (like PHP's other string functions) treats strings as a sequence of bytes, and since UTF-8 and other multibyte encodings use - by definition - more than one byte for at least some characters, the three-string form is likely to have problems. Use the associative array form to specify the mapping.

<?php
// Assuming UTF-8
$str = 'Äbc Äbc'; // strtr() sees this as nine bytes (including two for each Ä)
echo strtr($str, 'Ä', 'a'); // The second argument is equivalent to the string "\xc3\x84" so "\xc3" gets replaced by "a" and the "\x84" is ignored

echo strtr($str, array('Ä' => 'a')); // Works much better
?>

dcz at phpbb-seo dot com

2 years ago


strstr will issue a notice when $replace_pairs contains an array, even unused, with php 5.5.0.

It was not the case with version at least up to 5.3.2, but I'm not sure the notice was added with exactly 5.5.0.

<?php
$str = 'hi all, I said hello';
$replace_pairs = array(
      'all' => 'everybody',
    'unused' => array('somtehing', 'something else'),
     'hello' => 'hey',
);
// php 5.5.0 Notice: Array to string conversion in test.php on line 8
echo strtr($str, $replace_pairs); // hi everybody, I said hey
?>

since the result is still correct, @strstr seems a working solution.

doydoy44

2 years ago


The example of VOVA (http://www.php.net/manual/fr/function.strtr.php#111968) is good but the result is false:
His example dont replace the string.

<?php
function f1_strtr() {
  for($i=0; $i<1000000; ++$i) {
    $new_string = strtr("aboutdealers.com", array(".com" => ""));
  }
  return $new_string;
}
function f2_str_replace() {
  for($i=0; $i<1000000; ++$i) {
    $new_string = str_replace( ".com", "", "aboutdealers.com");
  }
  return $new_string;
}
$start = microtime(true);
$strtr = f1_strtr();
$stop = microtime(true);
$time_strtr = $stop - $start;
 
$start = microtime(true);
$str_replace = f2_str_replace();
$stop = microtime(true);
$time_str_replace = $stop - $start;
 
 
echo 'time strtr       : ' . $time_strtr       . "\tresult :" . $strtr       . "\n";
echo 'time str_replace : ' . $time_str_replace . "\tresult :" . $str_replace . "\n";
echo 'time strtr > time str_replace => ' . ($time_strtr > $time_str_replace);
?>
--------------------------------------
time strtr       : 3.9719619750977      result :aboutdealers
time str_replace : 2.9930369853973      result :aboutdealers
time strtr > time str_replace => 1

str_replace is faster than strtr

Tedy

3 years ago


Since strtr() is twice faster than strlwr I decided to write my own lowering function which also handles UTF-8 characters.

<?php

function strlwr($string, $utf = 1)
{
    $latin_letters = array('Ă' => 'a',
                            'Â' => 'a',
                            'Î' => 'i',
                            'Ș' => 's',
                            'Ş' => 's',
                            'Ț' => 't',
                            'Ţ' => 't');
                            
    $utf_letters = array('Ă' => 'ă',
                        'Â' => 'â',
                        'Î' => 'î',
                        'Ș' => 'ș',
                        'Ş' => 'ş',
                        'Ț' => 'ț',
                        'Ţ' => 'ţ');
                      
    $letters = array('A' => 'a',
                    'B' => 'b',
                    'C' => 'c',
                    'D' => 'd',
                    'E' => 'e',
                    'F' => 'f',
                    'G' => 'g',
                    'H' => 'h',
                    'I' => 'i',
                    'J' => 'j',
                    'K' => 'k',
                    'L' => 'l',
                    'M' => 'm',
                    'N' => 'n',
                    'O' => 'o',
                    'P' => 'p',
                    'Q' => 'q',
                    'R' => 'r',
                    'S' => 's',
                    'T' => 't',
                    'U' => 'u',
                    'V' => 'v',
                    'W' => 'w',
                    'X' => 'x',
                    'Y' => 'y',
                    'Z' => 'z');
    
    return ($utf == 1) ? strtr($string, array_merge($utf_letters, $letters)) : strtr($string, array_merge($latin_letters, $letters));
}

?>

This allows you to lower every character (even UTF-8 ones) if you don't set the second parameter, or just lower the UTF-8 ones into their specific latin characters (used when making friendly-urls for example). 

I used romanian characters but, of course, you can add your own local characters. 

Feel free to use/modify this function as you wish. Hope it helps.

patrick at p-roocks dot de

11 years ago


As Daijoubu suggested use str_replace instead of this function for large arrays/subjects. I just tried it with a array of 60 elements, a string with 8KB length, and the execution time of str_replace was faster at factor 20! 

Patrick

ktogias at math dot upatras dot gr

11 years ago


This function is usefull for 
accent insensitive regexp 
searches into greek (iso8859-7) text:
(Select View -> Character Encoding -> Greek (iso8859-7)
at your browser to see the correct greek characters)

function gr_regexp($mystring){
        $replacement=array(
                array("�","�","�","�"),
                array("�","�","�","�"),
                array("�","�","�","�"),
                array("�","�","�","�","�","�"),
                array("�","�","�","�"),
                array("�","�","�","�","�","�"),
                array("�","�","�","�")
        );
        foreach($replacement as $group){
                foreach($group as $character){
                        $exp="[";
                        foreach($group as $expcharacter){
                                $exp.=$expcharacter;
                        }
                        $exp.="]";
                        $trans[$character]=$exp;
                }
        }
        $temp=explode(" ", $mystring);
        for ($i=0;$i<sizeof($temp);$i++){
                $temp[$i]=strtr($temp[$i],$trans);
                $temp[$i]=addslashes($temp[$i]);
        }
        return implode(".*",$temp);
}

$match=gr_regexp("��������������������� ��� ��������");

//The next query string can be sent to MySQL
through mysql_query()
$query=
      "Select `column` from `table` where `column2` REGEXP   
                         '".$match."'";

Anonymous

11 years ago


If you are going to call strtr a lot, consider using str_replace instead, as it is much faster. I cut execution time in half just by doing this.

<?
// i.e. instead of:
$s=strtr($s,$replace_array);

// use: 
foreach($replace_array as $key=>$value) $s=str_replace($key,$value,$s);
?>

dot dot dot dot dot alexander at gmail dot com

8 years ago


Here is the stritr I always needed... I wrote it in 15 minutes... But only after the idea struck me. Hope you find it helpful, and enjoy...
<?php
if(!function_exists("stritr")){
    function stritr($string, $one = NULL, $two = NULL){
/*
stritr - case insensitive version of strtr
Author: Alexander Peev
Posted in PHP.NET
*/
        if(  is_string( $one )  ){
            $two = strval( $two );
            $one = substr(  $one, 0, min( strlen($one), strlen($two) )  );
            $two = substr(  $two, 0, min( strlen($one), strlen($two) )  );
            $product = strtr(  $string, ( strtoupper($one) . strtolower($one) ), ( $two . $two )  );
            return $product;
        }
        else if(  is_array( $one )  ){
            $pos1 = 0;
            $product = $string;
            while(  count( $one ) > 0  ){
                $positions = array();
                foreach(  $one as $from => $to  ){
                    if(   (  $pos2 = stripos( $product, $from, $pos1 )  ) === FALSE   ){
                        unset(  $one[ $from ]  );
                    }
                    else{
                        $positions[ $from ] = $pos2;
                    }
                }
                $winner = min( $positions );
                $key = array_search(  $winner, $positions  );
                $product = (   substr(  $product, 0, $winner  ) . $positions[$key] . substr(  $product, ( $winner + strlen($key) )  )   );
                $pos1 = (  $winner + strlen( $positions[$key] )  );
            }
            return $product;
        }
        else{
            return $string;
        }
    }/* endfunction stritr */
}/* endfunction exists stritr */
?>

elloromtz at gmail dot com

6 years ago


If you supply 3 arguments and the 2nd is an array, strtr will search the "A" from "Array" (because you're treating it as a scalar string) and replace it with the 3rd argument:

strtr('Analogy', array('x'=>'y'),  '_'); //'_nalogy'

so in reality the above code has the same affect as:

strtr('Analogy', 'A' , '_');

Michael Schuijff

4 years ago


I found that this approach is often faster than strtr() and won't change the same thing in your string twice (as opposed to str_replace(), which will overwrite things in the order of the array you feed it with):

<?php
function replace ($text, $replace) {
    $keys = array_keys($replace);
    $length = array_combine($keys, array_map('strlen', $keys));
    arsort($length);
    
    $array[] = $text;
    $count = 1;
    reset($length);
    while ($key = key($length)) {
        if (strpos($text, $key) !== false) {
            for ($i = 0; $i < $count; $i += 2) {
                if (($pos = strpos($array[$i], $key)) === false) continue;
                array_splice($array, $i, 1, array(substr($array[$i], 0, $pos), $replace[$key], substr($array[$i], $pos + strlen($key))));
                $count += 2;
            }
        }
        next($length);
    }
    return implode($array);
}
?>

ru dot dy at gmx dot net

10 years ago


Posting umlaute here resulted in a mess. Heres a version of the same function that works with preg_replace only:
<?php
  function getRewriteString($sString) {
     $string = strtolower(htmlentities($sString));
     $string = preg_replace("/&(.)(uml);/", "$1e", $string);
     $string = preg_replace("/&(.)(acute|cedil|circ|ring|tilde|uml);/", "$1", $string);
     $string = preg_replace("/([^a-z0-9]+)/", "-", html_entity_decode($string));
     $string = trim($string, "-");
     return $string;
  }
?>

gabi at unica dot edu

13 years ago


To convert special chars to their html entities strtr you can use strtr in conjunction with get_html_translation_table(HTML_ENTITIES) :

$trans = get_html_translation_table(HTML_ENTITIES);
$html_code = strtr($html_code, $trans); 

This will replace in $html_code the � by &Aacute; , etc.

allixsenos at gmail dot com

6 years ago


fixed "normaliza" functions written below to include Slavic Latin characters... also, it doesn't return lowercase any more (you can easily get that by applying strtolower yourself)...

also, renamed to normalize()

<?php

function normalize ($string) {
    $table = array(
        'Š'=>'S', 'š'=>'s', 'Đ'=>'Dj', 'đ'=>'dj', 'Ž'=>'Z', 'ž'=>'z', 'Č'=>'C', 'č'=>'c', 'Ć'=>'C', 'ć'=>'c',
        'À'=>'A', 'Á'=>'A', 'Â'=>'A', 'Ã'=>'A', 'Ä'=>'A', 'Å'=>'A', 'Æ'=>'A', 'Ç'=>'C', 'È'=>'E', 'É'=>'E',
        'Ê'=>'E', 'Ë'=>'E', 'Ì'=>'I', 'Í'=>'I', 'Î'=>'I', 'Ï'=>'I', 'Ñ'=>'N', 'Ò'=>'O', 'Ó'=>'O', 'Ô'=>'O',
        'Õ'=>'O', 'Ö'=>'O', 'Ø'=>'O', 'Ù'=>'U', 'Ú'=>'U', 'Û'=>'U', 'Ü'=>'U', 'Ý'=>'Y', 'Þ'=>'B', 'ß'=>'Ss',
        'à'=>'a', 'á'=>'a', 'â'=>'a', 'ã'=>'a', 'ä'=>'a', 'å'=>'a', 'æ'=>'a', 'ç'=>'c', 'è'=>'e', 'é'=>'e',
        'ê'=>'e', 'ë'=>'e', 'ì'=>'i', 'í'=>'i', 'î'=>'i', 'ï'=>'i', 'ð'=>'o', 'ñ'=>'n', 'ò'=>'o', 'ó'=>'o',
        'ô'=>'o', 'õ'=>'o', 'ö'=>'o', 'ø'=>'o', 'ù'=>'u', 'ú'=>'u', 'û'=>'u', 'ý'=>'y', 'ý'=>'y', 'þ'=>'b',
        'ÿ'=>'y', 'Ŕ'=>'R', 'ŕ'=>'r',
    );
    
    return strtr($string, $table);
}

?>

martin[dot]pelikan[at]gmail[dot]com

10 years ago


// if you are upset with windows' ^M characters at the end of the line,
// these two lines are for you:
$trans = array("\x0D" => "");
$text = strtr($orig_text,$trans);

// note that ctrl+M (in vim known as ^M) is hexadecimally 0x0D

Sidney Ricardo

7 years ago


This work fine to me:



<?php

function normaliza ($string){

    $a = 'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ

ßàáâãäåæçèéêëìíîïðñòóôõöøùúûýýþÿŔŕ';

    $b = 'aaaaaaaceeeeiiiidnoooooouuuuy

bsaaaaaaaceeeeiiiidnoooooouuuyybyRr'; 

    $string = utf8_decode($string);     

    $string = strtr($string, utf8_decode($a), $b);

    $string = strtolower($string);

    return utf8_encode($string);

}

?>

Romain

1 year ago


<?php
    /**
     * Clean string,
     * minimize and remove space, accent and other
     *
     * @param string $string
     * @return string
     */
    public function mb_strtoclean($string){
        // Valeur a nettoyer (conversion)
        $unwanted_array = array(    'Š'=>'S', 'š'=>'s', 'Ž'=>'Z', 'ž'=>'z', 'À'=>'A', 'Á'=>'A', 'Â'=>'A', 'Ã'=>'A', 'Ä'=>'A', 'Å'=>'A', 'Æ'=>'A', 'Ç'=>'C', 'È'=>'E', 'É'=>'E',
                                    'Ê'=>'E', 'Ë'=>'E', 'Ì'=>'I', 'Í'=>'I', 'Î'=>'I', 'Ï'=>'I', 'Ñ'=>'N', 'Ò'=>'O', 'Ó'=>'O', 'Ô'=>'O', 'Õ'=>'O', 'Ö'=>'O', 'Ø'=>'O', 'Ù'=>'U',
                                    'Ú'=>'U', 'Û'=>'U', 'Ü'=>'U', 'Ý'=>'Y', 'Þ'=>'B', 'ß'=>'Ss', 'à'=>'a', 'á'=>'a', 'â'=>'a', 'ã'=>'a', 'ä'=>'a', 'å'=>'a', 'æ'=>'a', 'ç'=>'c',
                                    'è'=>'e', 'é'=>'e', 'ê'=>'e', 'ë'=>'e', 'ì'=>'i', 'í'=>'i', 'î'=>'i', 'ï'=>'i', 'ð'=>'o', 'ñ'=>'n', 'ò'=>'o', 'ó'=>'o', 'ô'=>'o', 'õ'=>'o',
                                    'ö'=>'o', 'ø'=>'o', 'ù'=>'u', 'ú'=>'u', 'û'=>'u', 'ý'=>'y', 'ý'=>'y', 'þ'=>'b', 'ÿ'=>'y',
                                    ' ' => '', '_' => '', '-' => '', '.'=> '', ',' => '', ';' => '');

        return mb_strtolower(strtr($string, $unwanted_array ));
    }

ajitsingh4u at gmail dot com

8 years ago


/**
* Replaces special characters with single quote,double quote and comma for charset iso-8859-1
*
* replaceSpecialChars()
* @param string $str
* @return string
*/
function replaceSpecialChars($str)
{
    //`(96) ’(130) „(132) ‘(145) ’(146) “(147) ”(148) ´(180)   // equivalent ascii values of these characters.
    $str = strtr($str, "`’„‘’´", "'','''");
    $str = strtr($str, '“”', '""'); 
    return $str;
}

qeremy [atta] gmail [dotta] com

3 years ago


Weird, but strtr corrupting chars, if used like below and if file is encoded in UTF-8;

<?php
$str = 'Äbc Äbc';
echo strtr($str, 'Ä', 'a');
// output: a�bc a�bc
?>

And a simple solution;

<?php
function strtr_unicode($str, $a = null, $b = null) {
    $translate = $a;
    if (!is_array($a) && !is_array($b)) {
        $a = (array) $a;
        $b = (array) $b;
        $translate = array_combine(
            array_values($a),
            array_values($b)
        );
    }
    // again weird, but accepts an array in this case
    return strtr($str, $translate);
}

$str = 'Äbc Äbc';
echo strtr($str, 'Ä', 'a') ."\n";
echo strtr_unicode($str, 'Ä', 'a') ."\n";
echo strtr_unicode($str, array('Ä' => 'a')) ."\n";
// outputs
// a�bc a�bc
// abc abc
// abc abc
?>

j at pureftpd dot org

12 years ago


Here's a very useful function to translate Microsoft characters into Latin 15, so that people won't see any more square instead of characters in web pages .

function demicrosoftize($str) {
    return strtr($str,
"\x82\x83\x84\x85\x86\x87\x89\x8a" .
"\x8b\x8c\x8e\x91\x92\x93\x94\x95" .
"\x96\x97\x98\x99\x9a\x9b\x9c\x9e\x9f",
"'f\".**^\xa6<\xbc\xb4''" .
"\"\"---~ \xa8>\xbd\xb8\xbe");
}

tomhmambo at seznam dot cz

10 years ago


<?
// Windows-1250 to ASCII
// This function replace all Windows-1250 accent characters with 
// thier non-accent ekvivalents. Useful for Czech and Slovak languages.

function win2ascii($str)    {    

    $str = StrTr($str,
        "\xE1\xE8\xEF\xEC\xE9\xED\xF2",
        "\x61\x63\x64\x65\x65\x69\x6E");
        
    $str = StrTr($str,
        "\xF3\xF8\x9A\x9D\xF9\xFA\xFD\x9E\xF4\xBC\xBE",
        "\x6F\x72\x73\x74\x75\x75\x79\x7A\x6F\x4C\x6C");
        
    $str = StrTr($str,
        "\xC1\xC8\xCF\xCC\xC9\xCD\xC2\xD3\xD8",
        "\x41\x43\x44\x45\x45\x49\x4E\x4F\x52");
        
    $str = StrTr($str,
        "\x8A\x8D\xDA\xDD\x8E\xD2\xD9\xEF\xCF",
        "\x53\x54\x55\x59\x5A\x4E\x55\x64\x44");

    return $str;
}
?>

Fernando "Malk" Piancastelli

12 years ago


Here's a function to replace linebreaks to html <p> tags. This was initially designed to receive a typed text by a form in a "insert new notice" page and put in a database, then a "notice" page could get the text preformatted with paragraph tags instead of linebreaks that won't appear on browser. The function also removes repeated linebreaks the user may have typed in the form.

function break_to_tags(&$text) {

       // find and remove repeated linebreaks

       $double_break = array("\r\n\r\n" => "\r\n");
       do {
              $text = strtr($text, $double_break);
              $position = strpos($text, "\r\n\r\n");
       } while ($position !== false);

       // find and replace remanescent linebreaks by <p> tags

       $change = array("\r\n" => "<p>");
       $text = strtr($text, $change);
}

[]'s
Fernando

joeldegan AT yahoo

10 years ago


After battling with strtr trying to strip out MS word formatting from things pasted into forms I ended up coming up with this..

it strips ALL non-standard ascii characters, preserving html codes and such, but gets rid of all the characters that refuse to show in firefox.

If you look at this page in firefox you will see a ton of "question mark" characters and so it is not possible to copy and paste those to remove them from strings..  (this fixes that issue nicely, though I admit it could be done a bit better)

<?
function fixoutput($str){
    $good[] = 9;  #tab
    $good[] = 10; #nl
    $good[] = 13; #cr
    for($a=32;$a<127;$a++){
        $good[] = $a;
    }    
    $len = strlen($str);
    for($b=0;$b < $len+1; $b++){
        if(in_array(ord($str[$b]), $good)){
            $newstr .= $str[$b];
        }//fi
    }//rof
    return $newstr;
}
?>

bisqwit at iki dot fi

13 years ago


#!/bin/sh
# This shell script generates a strtr() call
# to translate from a character set to another.
# Requires: gnu recode, perl, php commandline binary
#
# Usage:
#  Set set1 and set2 to whatever you prefer
#  (multibyte character sets are not supported)
#  and run the script. The script outputs
#  a strtr() php code for you to use.
#
# Example is set to generate a
# cp437..latin9 conversion code.
#
set1=cp437
set2=iso-8859-15
result="`echo '<? for($c=32;$c<256;$c++)'\
              'echo chr($c);'\            
         |php -q|recode -f $set1..$set2`"
echo "// This php function call converts \$string in $set1 to $set2";
cat <<EOF  | php -q
<?php
\$set1='`echo -n "$result"\
   |perl -pe "s/([\\\\\'])/\\\\\\\\\\$1/g"`';
\$set2='`echo -n "$result"|recode -f $set2..$set1\
   |perl -pe "s/([\\\\\'])/\\\\\\\\\\$1/g"`';
\$erase=array();
\$l=strlen(\$set1);
for(\$c=0;\$c<\$l;++\$c)
  if(\$set1[\$c]==\$set2[\$c])\$erase[\$set1[\$c]]='';
if(count(\$erase))
{
  \$set1=strtr(\$set1,\$erase);
  \$set2=strtr(\$set2,\$erase);
}
if(!strlen(\$set1))echo 'IRREVERSIBLE';else
echo "strtr(\\\$string,\n  '",
     ereg_replace('([\\\\\\'])', '\\\\\\1', \$set2),
     "',\n  '",
     ereg_replace('([\\\\\\'])', '\\\\\\1', \$set1),
     "');";
EOF

Sam

4 years ago


Case Insensitive strtr



<?php

function stritr($string, $one, $two=null) {

    if (is_string($one)) {

        return strtr($string, strtoupper($one) . strtolower($one), "$two$two");

    } else if (is_array($one)) {

        $strReturn = $string

        foreach ($one as $key => $val) {

            $strReturn = preg_replace("'$key'i", $val, $strReturn);

        }

        return $strReturn;

    }

    return $string;

}

?>

troelskn at gmail dot com

8 years ago


Here's another transcribe function. This one converts cp1252 (aka. Windows-1252) into iso-8859-1 (aka. latin1, the default PHP charset). It only transcribes the few exotic characters, which are unique to cp1252.

function transcribe_cp1252_to_latin1($cp1252) {
  return strtr(
    $cp1252,
    array(
      "\x80" => "e",  "\x81" => " ",    "\x82" => "'", "\x83" => 'f',
      "\x84" => '"',  "\x85" => "...",  "\x86" => "+", "\x87" => "#",
      "\x88" => "^",  "\x89" => "0/00", "\x8A" => "S", "\x8B" => "<",
      "\x8C" => "OE", "\x8D" => " ",    "\x8E" => "Z", "\x8F" => " ",
      "\x90" => " ",  "\x91" => "`",    "\x92" => "'", "\x93" => '"',
      "\x94" => '"',  "\x95" => "*",    "\x96" => "-", "\x97" => "--",
      "\x98" => "~",  "\x99" => "(TM)", "\x9A" => "s", "\x9B" => ">",
      "\x9C" => "oe", "\x9D" => " ",    "\x9E" => "z", "\x9F" => "Y"));

horak.jan AT centrum.cz

8 years ago


Here is a function to convert middle-european windows charset (cp1250) to the charset, that php script is written in:

<?php
    function cp1250_to_utf2($text){
        $dict  = array(chr(225) => 'á', chr(228) =>  'ä', chr(232) => 'č', chr(239) => 'ď', 
            chr(233) => 'é', chr(236) => 'ě', chr(237) => 'í', chr(229) => 'ĺ', chr(229) => 'ľ', 
            chr(242) => 'ň', chr(244) => 'ô', chr(243) => 'ó', chr(154) => 'š', chr(248) => 'ř', 
            chr(250) => 'ú', chr(249) => 'ů', chr(157) => 'ť', chr(253) => 'ý', chr(158) => 'ž',
            chr(193) => 'Á', chr(196) => 'Ä', chr(200) => 'Č', chr(207) => 'Ď', chr(201) => 'É', 
            chr(204) => 'Ě', chr(205) => 'Í', chr(197) => 'Ĺ',    chr(188) => 'Ľ', chr(210) => 'Ň', 
            chr(212) => 'Ô', chr(211) => 'Ó', chr(138) => 'Š', chr(216) => 'Ř', chr(218) => 'Ú', 
            chr(217) => 'Ů', chr(141) => 'Ť', chr(221) => 'Ý', chr(142) => 'Ž', 
            chr(150) => '-');
        return strtr($text, $dict);
    }
?>

hotmail - marksteward

13 years ago


Referring to note from 11 October 2000, Thorn (�, �), Eth (�, �), Esset (�) and Mu (�) aren't really accented letters.  �, �, �, � are ligatures.  Best to do the following:

function removeaccents($string){
 return strtr(
  strtr($string,
   '������������������������������������������������������������',
   'SZszYAAAAAACEEEEIIIINOOOOOOUUUUYaaaaaaceeeeiiiinoooooouuuuyy'),
  array('�' => 'TH', '�' => 'th', '�' => 'DH', '�' => 'dh', '�' => 'ss',
   '�' => 'OE', '�' => 'oe', '�' => 'AE', '�' => 'ae', '�' => 'u'));
}

This would be no good for sorting, as thorn and eth aren't actually found under th and dh.  Also especially redundant because of Unicode!  Still, I'm sure somone can find use for it - perhaps to constrict filenames...

Mark

volkris at tamu dot edu

12 years ago


Regarding christophe's conversion, note that the \x## values should be in double quotes, not single, so that the escape will be applied.

stewey at ambitious dot ca

12 years ago


This version of macRomanToIso (originally posted by: marcus at synchromedia dot co dot uk) offers a couple of improvements. First, it removes the extra slashes '\' that broke the original function. Second, it adds four quote characters not supported in ISO 8859-1. These are the left double quote, right double quote, left single quote and right single quote.



Be sure to remove the line breaks from the two strings going into strtr or this function will not work properly.



Be careful what text you apply this to. If you apply it to ISO 8859-1 encoded text it will likely wreak havoc. I'll save you some trouble with this bit of advice: don't bother trying to detect what charset a certain text file is using, it can't be done reliably. Instead, consider making assumptions based upon the HTTP_USER_AGENT, or prompting the user to specify the character encoding used (perhaps both).



<?php



/**

 * Converts MAC OS ROMAN encoded strings to the ISO 8859-1 charset.

 *

 * @param    string    the string to convert.

 * @return    string    the converted string.

 */

function macRomanToIso($string)

{

    return strtr($string,

"\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b

\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97

\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa1\xa4\xa6\xa7

\xa8\xab\xac\xae\xaf\xb4\xbb\xbc\xbe\xbf\xc0\xc1

\xc2\xc7\xc8\xca\xcb\xcc\xd6\xd8\xdb\xe1\xe5\xe6

\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf1\xf2\xf3

\xf4\xf8\xfc\xd2\xd3\xd4\xd5",

"\xc4\xc5\xc7\xc9\xd1\xd6\xdc\xe1\xe0\xe2\xe4\xe3

\xe5\xe7\xe9\xe8\xea\xeb\xed\xec\xee\xef\xf1\xf3

\xf2\xf4\xf6\xf5\xfa\xf9\xfb\xfc\xb0\xa7\xb6\xdf\xae

\xb4\xa8\xc6\xd8\xa5\xaa\xba\xe6\xf8\xbf\xa1\xac

\xab\xbb\xa0\xc0\xc3\xf7\xff\xa4\xb7\xc2\xca\xc1

\xcb\xc8\xcd\xce\xcf\xcc\xd3\xd4\xd2\xda\xdb\xd9

\xaf\xb8\x22\x22\x27\x27");

}



?>

lichail at sohu dot com

2 years ago


<?php
//note this output null
echo strtr('abc', array('' => ''));
?>

Chris

5 years ago


Hope this is useful when you need to see ASCII control characters:
<?php
$xlate = array(chr(0) => '^@/NUL/null', chr(1) => '^A/SOH/start of heading', chr(2) => '^B/STX/start of text', chr(3) => '^C/ETX/end of text', chr(4) => '^D/EOT/end of transmisssion', chr(5) => '^E/ENQ/enquiry', chr(6) => '^F/ACK/acknowledge', chr(7) => '^G/BEL/bell', chr(8) => '^H/BS/backspace', chr(9) => '^I/TAB/horizontal tab', chr(10) => '^J/LF/NL/line feed/new line', chr(11) => '^K/VT/vertical tab', chr(12) => '^L/FF/NP/form feed/new page/', chr(13) => '^M/CR/carrige return', chr(14) => '^N/SO/shift out', chr(15) => '^O/SI/shift in', chr(16) => '^P/DLE/data link escape', chr(17) => '^Q/DC1/device control 1', chr(18) => '^R/DC2/device control 2', chr(19) => '^S/DC3/device control 3', chr(20) => '^T/DC4/device control 4', chr(21) => '^U/NAK/negative acknowledge', chr(22) => '^V/SYN/synchronous idle', chr(23) => '^W/ETB/end of transmission block', chr(24) => '^X/CAN/cancel', chr(25) => '^Y/EM/end of medium', chr(26) => '^Z/SUB/substiute', chr(27) => '^[/ESC/escape', chr(28) => '^\/FS/file separator', chr(29) => '^]/GS/group separator', chr(30) => '^^/RS/record separator', chr(31) => '^_/US/unit separator', chr(32) => 'Space');

$x = 0;
$pad = strlen(strlen($str));
while(isset($str[$x]))
   echo 'character ', str_pad($x+1, $pad), ' = ', strtr($str[$x], $xlate), ' (ascii ', ord($str[$x++]), ')';
?>

patrick dot rauchfuss at gmail dot com

3 years ago


Here my solution of an classes recursive caseinsentive strtr..

<?php
class String
{
    public static function stritr(&$string, $from, $to = NULL)
    {
        if(is_string($from))
            $string = preg_replace("'$from'i", $to, $string);

        else if(is_array($from))
        {
            foreach ($from as $key => $val)
                self::stritr($string, $key, $val);
        }
        
        return $string;
    }
}

// example:
$string = "Hello world. This is just a simple test";
print String::stritr($string, 'WorLd', 'foo');

// array example:
print String::stritr($string, array('WorLd' => 'foo', 'TEST' => 'bar'));
?>

symlink23-remove-my-spleen at yahoo dot com

14 years ago


As noted in the str_rot13 docs, some servers don't provide the str_rot13() function. However, the presence of strtr makes it easy to build your own facsimile thereof:

if (!function_exists('str_rot13')) {
    function str_rot13($str) {
        $from = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $to   = 'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM';

        return strtr($str, $from, $to);
    }
}

This is suitable for very light "encryption" such as hiding email addressess from spambots (then unscrambling them in a mail class, for example).

$mail_to=str_rot13("$mail_to");

erik at eldata dot se

14 years ago


As an alternative to the not-yet-existing function stritr mentioned in the first note above You can easily do this:



strtr("abc","ABCabc","xyzxyz")



or more general:



strtr("abc",

strtoupper($fromchars).strtolower($fromchars),

$tochars.$tochars);



Just a thought.

m dot frank at beam dot ag

13 years ago


to get the ascii equivalent of unicode characters simply use the
 
utf8_decode() function

antimoz at gmail dot com

4 years ago


Here is my array for char normalization:

<?php

        $normalizeChars = array(

            'Á'=>'A', 'À'=>'A', 'Â'=>'A', 'Ã'=>'A', 'Å'=>'A', 'Ä'=>'A', 'Æ'=>'AE', 'Ç'=>'C',

            'É'=>'E', 'È'=>'E', 'Ê'=>'E', 'Ë'=>'E', 'Í'=>'I', 'Ì'=>'I', 'Î'=>'I', 'Ï'=>'I', 'Ð'=>'Eth',

            'Ñ'=>'N', 'Ó'=>'O', 'Ò'=>'O', 'Ô'=>'O', 'Õ'=>'O', 'Ö'=>'O', 'Ø'=>'O',

            'Ú'=>'U', 'Ù'=>'U', 'Û'=>'U', 'Ü'=>'U', 'Ý'=>'Y',

    

            'á'=>'a', 'à'=>'a', 'â'=>'a', 'ã'=>'a', 'å'=>'a', 'ä'=>'a', 'æ'=>'ae', 'ç'=>'c',

            'é'=>'e', 'è'=>'e', 'ê'=>'e', 'ë'=>'e', 'í'=>'i', 'ì'=>'i', 'î'=>'i', 'ï'=>'i', 'ð'=>'eth',

            'ñ'=>'n', 'ó'=>'o', 'ò'=>'o', 'ô'=>'o', 'õ'=>'o', 'ö'=>'o', 'ø'=>'o',

            'ú'=>'u', 'ù'=>'u', 'û'=>'u', 'ü'=>'u', 'ý'=>'y',

            

            'ß'=>'sz', 'þ'=>'thorn', 'ÿ'=>'y'

        );

?>

oliver at modix dot de

11 years ago


Replace control characters in a binary string:
<?

function cc_replace($in) {
        for ($i = 0; $i <= 31; $i++) {
                $from  .= chr($i);
                $to    .= ".";
        }
        return strtr($in, $from, $to);
}

?>

Ezbakhe Yassin <yassin88 at gmail dot com>

10 years ago


Here you are a simple function to rotate a variable according to an array of possible values. You can make a strict comparison (===).

<?php
function rotateValue($string, $values, $strict = TRUE)
{
    if (!empty($string) AND is_array($values))
    {
        $valuesCount = count($values);

        for ($i = 0; $i < $valuesCount; $i++)
        {
            if ($strict ? ($string === $values[$i]) : ($string == $values[$i]))
            {
                return $values[($i + 1) % $valuesCount];
            }
        }
    }

    return FALSE;
}
?>

For example:

- rotateValue("A", array("A", "B", "C")) will return "B"
- rotateValue("C", array("A", "B", "C")) will return "A"

strtr

Description

Parameters

Return Values

Examples

See Also

User Contributed Notes