strtoupper

strtok

Last updated: Fri, 20 Nov 2009

strtolower

(PHP 4, PHP 5)

strtolower — Make a string lowercase

Description

string strtolower ( string $str )

Returns string with all alphabetic characters converted to lowercase.

Note that 'alphabetic' is determined by the current locale. This means that in i.e. the default "C" locale, characters such as umlaut-A (Ä) will not be converted.

Parameters

str: The input string.

Return Values

Returns the lowercased string.

Examples

Example #1 strtolower() example


<?php
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = strtolower($str);
echo $str; // Prints mary had a little lamb and she loved it so
?>

Notes

Note: This function is binary-safe.


the strtolower version to support most amount of languages including russian, french and so on:





<?php


function strtolower_utf8($string){


  $convert_to = array(


    "a", "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", "à", "á", "â", "ã", "ä", "å", "æ", "ç", "è", "é", "ê", "ë", "ì", "í", "î", "ï", 


    "ð", "ñ", "ò", "ó", "ô", "õ", "ö", "ø", "ù", "ú", "û", "ü", "ý", "а", "б", "в", "г", "д", "е", "ё", "ж", 


    "з", "и", "й", "к", "л", "м", "н", "о", "п", "р", "с", "т", "у", "ф", "х", "ц", "ч", "ш", "щ", "ъ", "ы", 


    "ь", "э", "ю", "я"


  );


  $convert_from = array(


    "A", "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", "À", "Á", "Â", "Ã", "Ä", "Å", "Æ", "Ç", "È", "É", "Ê", "Ë", "Ì", "Í", "Î", "Ï", 


    "Ð", "Ñ", "Ò", "Ó", "Ô", "Õ", "Ö", "Ø", "Ù", "Ú", "Û", "Ü", "Ý", "А", "Б", "В", "Г", "Д", "Е", "Ё", "Ж", 


    "З", "И", "Й", "К", "Л", "М", "Н", "О", "П", "Р", "С", "Т", "У", "Ф", "Х", "Ц", "Ч", "Ш", "Щ", "Ъ", "Ъ", 


    "Ь", "Э", "Ю", "Я"


  );





  return str_replace($convert_from, $convert_to, $string);


}


?>

Khigashi
22-Jun-2009 09:53


Here is my code, I made because of the accents contained in the latin languages [like the Portuguese of Brazil =)]





<?php


function deepLower($texto){


    //Letras minúsculas com acentos


    $texto = strtr($texto, "


    ĄĆĘŁŃÓŚŹŻABCDEFGHIJKLMNOPRSTUWYZQ


    XVЁЙЦУКЕНГШЩЗХЪФЫВАПРОЛДЖЭЯЧСМИТЬБЮ


    ÂÀÁÄÃÊÈÉËÎÍÌÏÔÕÒÓÖÛÙÚÜÇ


    ", "


    ąćęłńóśźżabcdefghijklmnoprstuwyzq


    xvёйцукенгшщзхъфывапролджэячсмитьбю


    âàáäãêèéëîíìïôõòóöûùúüç


    ");


    return strtolower($texto);


}


?>

hans111 {AT} yahoo {DOT} com
13-May-2009 10:02


Could be useful, if mb string library is not available for whatever the reason:


<?php


    function utf8_strtolower($string) {


        return utf8_encode(strtolower(utf8_decode($string)));


    }


##equally..... 


    function utf8_ucfirst($string) {


        return utf8_encode(ucfirst(utf8_decode($string)));


    }


#.....etc...


?>


It has worked for me, just make sure you feed the functions with the proper encoded text (utf-8)





[These functions] only work when translation is between common characters in ISO 8859-1 and UTF-8, that means they will work well with western languages but not cyrillic or asian.

coder at bulgaria dot bg
04-Apr-2009 12:08


for cyrillic and UTF 8 use  mb_convert_case





exampel





<?php


$string = "Австралия";


$string = mb_convert_case($string, MB_CASE_LOWER, "UTF-8");


echo $string;





//output is: австралия


?>

ghutix6 at gmail dot com
15-Mar-2009 09:50


Here is function for working polish lower letters (plus example):



<?php

  

  function lower_pl($str)

   {

     return strtr($str, "ĄĆĘŁŃÓŚŹŻABCDEFGHIJKLMNOPRSTUWYZQXV", "ąćęłńóśźżabcdefghijklmnoprstuwyzqxv");

   }

 

  $word ="ŻÓŁTKO";

  $word = lower_pl ($word);



  echo ("<p>$word</p>");   

 

?>



This will turn into: <p>żółtko</p>.

dbers26 at gmail dot com
07-Jan-2009 09:34


the function  arraytolower will create duplicate entries since keys are case sensitive.  





<?php


$array = array('test1' => 'asgAFasDAAd', 'TEST2' => 'ASddhshsDGb', 'TeSt3 '=> 'asdasda@asdadadASDASDgh');





$array = arraytolower($array);


?>


/*


Array


(


    [test1] => asgafasdaad


    [TEST2] => ASddhshsDGb


    [TeSt3] => asdasda@asdadadASDASDgh


    [test2] => asddhshsdgb


    [test3] => asdasda@asdadadasdasdgh


)


*/





I prefer this method





<?php


  function arraytolower($array, $include_leys=false) {


    


    if($include_leys) {


      foreach($array as $key => $value) {


        if(is_array($value))


          $array2[strtolower($key)] = arraytolower($value, $include_leys);


        else


          $array2[strtolower($key)] = strtolower($value);


      }


      $array = $array2;


    }


    else {


      foreach($array as $key => $value) {


        if(is_array($value))


          $array[$key] = arraytolower($value, $include_leys);


        else


          $array[$key] = strtolower($value);   


      }


    }


    


    return $array;


  } 


?>





which when used like this





<?php


$array = $array = array('test1' => 'asgAFasDAAd', 'TEST2' => 'ASddhshsDGb', 'TeSt3 '=> 'asdasda@asdadadASDASDgh');





$array1 = arraytolower($array);


$array2 = arraytolower($array,true);





print_r($array1);


print_r($array2);


?>





will give output of 





Array


(


    [test1] => asgafasdaad


    [TEST2] => asddhshsdgb


    [TeSt3] => asdasda@asdadadasdasdgh


)


Array


(


    [test1] => asgafasdaad


    [test2] => asddhshsdgb


    [test3] => asdasda@asdadadasdasdgh


)

s0urce at anonyme dot com
23-Oct-2008 10:05


for someone who needs - arraytolower:





<?php


function arraytolower($array,$round = 0){


    foreach($array as $key => $value){


        if(is_array($value)) $array[strtolower($key)] =  $this->arraytolower($value,$round+1);


        else $array[strtolower($key)] = strtolower($value); 


        }


        return $array;


    }


?>





converts the whole array in a levels. keys and values.

rodrigoATsistemasparainternetDOTcomDOTbr
10-Sep-2008 01:25


<?php

function fullLower($str){

   // convert to entities

   $subject = htmlentities($str,ENT_QUOTES);

   $pattern = '/&([a-z])(uml|acute|circ';

   $pattern.= '|tilde|ring|elig|grave|slash|horn|cedil|th);/e';

   $replace = "'&'.strtolower('\\1').'\\2'.';'";

   $result = preg_replace($pattern, $replace, $subject);

   // convert from entities back to characters

   $htmltable = get_html_translation_table(HTML_ENTITIES);

   foreach($htmltable as $key => $value) {

      $result = ereg_replace(addslashes($value),$key,$result);

   }

   return(strtolower($result));

}



echo fullLower("Ã É Ò Õ ÚÙÛ");



//results ã é ò õ úùû

//adapted from fullUpper on strtoupper manual

?>

concepton at gmail dot com
11-Aug-2008 04:50


comment to "alexfort at list dot ru"





i think better to use this one





<?php 


function strtolower_ru($text) {


    $alfavitlover = array('ё','й','ц','у','к','е','н','г', 'ш','щ','з','х','ъ','ф','ы','в', 'а','п','р','о','л','д','ж','э', 'я','ч','с','м','и','т','ь','б','ю');


    $alfavitupper = array('Ё','Й','Ц','У','К','Е','Н','Г', 'Ш','Щ','З','Х','Ъ','Ф','Ы','В', 'А','П','Р','О','Л','Д','Ж','Э', 'Я','Ч','С','М','И','Т','Ь','Б','Ю');





    return str_replace($alfavitupper,$alfavitlover,strtolower($text));


}


?>

alexfort at list dot ru
04-Aug-2008 12:43


<?php

//solution to the Cyrillic and uft-8

function strtolower_Cyrillic($word) {

    $alfavitlover = explode(',', 'ё,й,ц,у,к,е,н,г,ш,щ,з,х,ъ,ф,ы,

    в,а,п,р,о,л,д,ж,э,я,ч,с,м,и,т,ь,б,ю');

    $alfavitupper = explode(',', 'Ё,Й,Ц,У,К,Е,Н,Г,Ш,Щ,З,Х,Ъ,Ф,Ы,

    В,А,П,Р,О,Л,Д,Ж,Э,Я,Ч,С,М,И,Т,Ь,Б,Ю');

    for($wr=0;$wr<=count($alfavitlover);$wr++) {

        $word = str_replace($alfavitupper[$wr], $alfavitlover[$wr], $word);

    }

    return $word;

}

echo strtolower_Cyrillic('СаШа+МаШа');

?>

tushar at sel2in dot com
28-Jul-2008 03:57


Quick and works for accented characters like á





Tested on linux and win apache+php5





<?php


function strtolower2($s){


    $ln = strlen($s);


    $ln1 = $ln -1;


    for($i=0; $i < $ln; $i++){


        $k = ord(substr($s, $i, 1));


        if($k>=65 && $k <= 90){


            if($i > 0){


                $l1 = substr($s, 0, $i);


            }else{


                $l1 ='';


            }


            $l1 = $l1 . chr($k+32);


            if($i < $ln1){


                $l1 = $l1 . substr($s, $i  + 1);


            }


            $s = $l1;





        }


    }


    return $s;


}


?>

Piotr
10-Mar-2008 09:24


///charset=iso-8859-2

 function strtolower_iso8592($string)

    {

        $low=array("ˇ" => "±", "Ć" => "ć", "Ę" => "ę", "Ł" => "ł", "Ó" => "ó", "¦" => "¶", "Ż" => "ż", "¬" => "Ľ", "Ń" => "ń");

        return strtolower(strtr($string,$low));

        

        

        

    }

toringe at infostill dot com
25-Oct-2007 10:27


This will work for all languages using ISO8859_1 - more code than many other but fast.



<?php

function strtolower_iso8859_1($s){

    $i = strlen($s);

    while ($i > 0) {

        --$i;

        $c =ord($s[$i]);

        if (($c & 0xC0) == 0xC0) {

            // two most significante bits on

            if (($c != 215) and ($c != 223)){ // two chars OK as is

                // to get lowercase set 3. most significante bit if needed:

                $s[$i] = chr($c | 0x20);

            }

        }

    }

    return strtolower($s);

}    

?>

patricia at steuerungb dot de
17-Oct-2007 01:29


When you're not sure, how the current locale is set, you might find the following function useful. It's strtolower for utf8-formatted text:



<?php

function strtolower_utf8($inputString) {

    $outputString    = utf8_decode($inputString);

    $outputString    = strtolower($outputString);

    $outputString    = utf8_encode($outputString);

    return $outputString;

}

?>



It's not suitable for every occasion, but it surely gets in handy. I use it for lowering German 'Umlauts' like ä and ö.

mr dot blober at gmail dot com
16-Jun-2007 06:39


simple example for Polish characters

<?php

function strtolower_pl($str) 

{

return strtr(strtolower($str), '[ĄĆĘŁŃÓŚŹŻ]', '[ąćęłńóśźż]');

}

?>

rok dot kralj at gmail dot com
04-Jun-2007 06:49


Slovenian characters



<?php

    function strtolower_slovenian($string)

    {

        $low=array("Č" => "č", "Ž" => "ž", "Š" => "š");

        return strtolower(strtr($string,$low));

    }



?>

marco at recchiuti dot it
22-May-2007 07:43


Maybe it is not so elegant, but it Works.

It's just a fast Idea and it is what I need.

Any hacks for other characters (link !, ? etc etc) should help.



function RemoveShouting($string)

{

     $frase = "";    

     $astri = explode(".", $string);

     foreach ($astri as $elem)

    $frase .= " ".ucfirst(trim(strtolower($elem))).". ";

       

    return trim($frase);

}



Cheers!

M

mario dot kostelac at gmail dot com
29-Apr-2007 11:42


This is strtolower function for Croatian characters:

function strToLowerCro($string){

    $string = strtolower($string);

    $patterns[0] = '/Č/';

    $patterns[1] = '/Ć/';

    $patterns[2] = '/Ž/';

    $patterns[3] = '/Š/';

    $patterns[4] = '/Đ/';

    $replacements[0] = 'č';

    $replacements[1] = 'ć';

    $replacements[2] = 'ž';

    $replacements[3] = 'š';

    $replacements[4] = 'đ';

    $string = preg_replace($patterns, $replacements, $string);

    return $string;

}

Enjoy...

HQ063
31-Mar-2007 08:37


Similar to last function, but for spanish

    function strtolower_es($string)

    {

        $low=array("Á" => "á", "É" => "é", "Í" => "í", "Ó" => "ó", "Ú" => "ú", "Ü" => "ü", "Ñ" => "ñ");

        return strtolower(strtr($string,$low));

    }

Dinçer Akay
20-Dec-2006 10:32


Turkish Character

<?php

    function strtolower_tr($string)

    {

        $low=array("Ü" => "ü", "Ö" => "ö", "Ğ" => "ğ", "Ş" => "ş", "Ç" => "ç", "İ" => "i", "I" => "ı");

        return strtolower(strtr($string,$low));

    }



?>

Enzo_01 at abv dot bg
07-Nov-2006 07:31


two functions what works with cyrilic text



function cyr_strtolower($a) {

        $offset=32;

        $m=array();

        for($i=192;$i<224;$i++)$m[chr($i)]=chr($i+$offset);

        return strtr($a,$m);

}

function cyr_strtoupper($a) {

        $offset=32;

        $m=array();

        for($i=192;$i<224;$i++)$m[chr($i+$offset)]=chr($i);

        return strtr($a,$m);

}



ex:

 cyr_strtoupper("абвгде"); // АБВГДЕ

 cyr_strtolower("АБВГДЕ"); // абвгде

eduardor2k at redr2k dot com
08-Aug-2006 09:34


I changed it a bit and i found that it's better to put everything in lowercase, and rebuild the text the same way a teacher corrects a text, for now it only checks that the first letter after a point "." must be

in upper case.



    function RemoveShouting($string)

    {

        $string = strtolower(trim($string));

       

        for($i=0;$i<strlen($string);$i++){

       

            if($i==0){$string[$i] = strtoupper($string[$i]);}

           

            if($string[$i] == "."){

                while($string[$i+1] == " "){

                    $i++;

                }

                $string[$i+1] = strtoupper($string[$i+1]);

                $i++;

            }

        }

       

    return $string;

    }



this function would change:

Hi mi name is PETER. SOME TIMES I FORGOT TO DISABLE CAPS LOCK.



into:



Hi mi name is peter. Some times i forgot to disable caps lock.

spiceee ddotty spiceee com
07-Mar-2006 12:53


If you ever need to strtolower a string with href tags on it and doesn't want to mess with the characters inside a tag, this is for you.



<?php



function loweroutsidetags ($str) {

    $chars = preg_split ("//", $str);

    $tolower = true;

    $str = '';



    foreach ($chars as $k) {

        if ($k == '<') { $tolower = false; }

        if ($tolower) { $k = strtolower ($k); }

        $str .= $k;    

        if ($k == '>') { $tolower = true; }

    }

    return $str;

}



?>



this: 

echo loweroutsidetags('aALalala <a href="?q=CASEsENSITIVINESSinURLSareSTUPID">')



will give:

aalalala <a href="?q=CASEsENSITIVINESSinURLSareSTUPID">

red at iklanumum dot com
24-Feb-2006 02:43


I've seen this as a common use from script developers, so I would like to share the alternative way to compare 2 string (CASE INSENSITIVE) without using strtolower for faster process.



Use strcasecmp() for comparison purpose rather than comparing uncertain case of 2 string variables, because strcasecmp() is approximately 60% faster, moreover, the greater its string length the greater the difference,!

Ex. case :

$var1;    -> could be a mixture of upper & lower case

$var2;    -> could be a mixture of upper & lower case



To compare whether $var1 is exactly the same as $var2 (case insensitive manner):

Use -> if (strcasecmp($var1,$var2)==0)

rather than -> if (strtolower($var1)==strtolower($var2))

Patrick
19-Jan-2006 06:57


If you're considering using the below unhtmlentities function from phpContrib, I would suggest this one as an alternative:



<?php

function unhtmlentities($string)

{

   // replace numeric entities

   $string = preg_replace('~&#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $string);

   $string = preg_replace('~&#([0-9]+);~e', 'chr(\\1)', $string);

   // replace literal entities

   $trans_tbl = get_html_translation_table(HTML_ENTITIES);

   $trans_tbl = array_flip($trans_tbl);

   return strtr($string, $trans_tbl);

}

?>



That was copied exactly from the html_entity_decode manual page.  It'll handle numeric entities correctly, the below function won't.

fackelkind
11-Jan-2006 08:03


Nifty? :D



<?php

        function is_lowercase ($str){

                return ($str == strtolower ($str));

        }

?>

mhuggins57 at yahoo dot com
19-Jul-2005 11:04


There's a ucfirst "function" to make the first character uppercase, but there's no "lcfirst" function to make the first character lowercase.  Here's my own code to accomplish this.



<?

function lcfirst($str) {

    return strtolower(substr($str, 0, 1)) . substr($str, 1);

}

?>



I found this particularly useful for generating XML nodes with the Reflection class.

kmcdermott at perimeterinstitute dot ca
08-Dec-2004 09:04


To do case insensitive comparisons in a database, strtolower() can be a quick and dirty solution:



$Sql = "SELECT * FROM tablename WHERE LOWER(column_name) = '".strtolower($my_var)."'";

phpContrib (A T) esurfers d o t c o m
24-Sep-2004 06:07


<?php



$b=html_entity_decode(strtolower(htmlentities($a)));



?>



will convert to lowercase most accented vocals

(it will convert � into &Agrave; into &agrave; into �)



This is not fast and clean code, it is just a quick oneliner to help you if you need a quick way to do it 



�



Users with older versions of PHP can use:

$b=unhtmlentities(strtolower(htmlentities($a)));



// with unhtmlentities() as defined in the html_entity_decode() manual page:



function unhtmlentities ($string) {

    $trans_tbl =get_html_translation_table (HTML_ENTITIES ); 

    $trans_tbl =array_flip ($trans_tbl ); 

    return strtr ($string ,$trans_tbl ); 

}

bkimble at ebaseweb dot com
20-Jan-2003 06:39


Heres a small function I wrote to stop people from submitting data that is ALL IN CAPS SO THEY CAN GET MORE ATTENTION THAT THE REST OF THE USER SUBMITTED DATA on my website :) If you can make it better, by all means do so. This function splits up words delimited by a space, and makes only the first letter of each word capitalized. You can easily modify it so it's only the very first word of the string. I've also added some exceptions so you don't make things like roman numerals look like "Iii" or "Xcmii" or something.



function RemoveShouting($string)

{

 $lower_exceptions = array( 

        "to" => "1", "a" => "1", "the" => "1", "of" => "1"

 ); 

 

 $higher_exceptions = array(  

        "I" => "1", "II" => "1", "III" => "1", "IV" => "1",  

        "V" => "1", "VI" => "1", "VII" => "1", "VIII" => "1",

        "XI" => "1", "X" => "1"

 ); 

 

 $words = split(" ", $string); 

 $newwords = array(); 

 foreach ($words as $word)

 {

  if (!$higher_exceptions[$word]) $word = strtolower($word);

  if (!$lower_exceptions[$word]) $word[0] = strtoupper($word[0]);

  array_push($newwords, $word);

 }

 return join(" ", $newwords);

}



BK

tty01_at_rambler_dot_ru
20-Sep-2002 02:58


Another solution for Double-Byte-Characters, based on iconv() functions, not sensible to the current locale, works on win32.



/* Converts charset */

function myConvertCharset($str, $from, $to)

{

    if(@function_exists('iconv'))

    {

        return iconv($from, $to, $str);

    }

    else if(@function_exists('recode_string'))

    {

        return recode_string($from . '..'  . $to, $str);

    }

    else

    {

        print "function iconv not exists";

        return $str;

    }

}

/* Converts a string to lowercase */

function my_strtolower($s)

{

    $t = "windows-1251";

    $d = "UTF-8";

    return myConvertCharset(strtolower(myConvertCharset($s, $d, $t)), $t, $d);

}



print my_strtolower("СЛОВО  Uppercase");

13-Sep-2002 12:17


This function is sensible to the current locale, namely the LC_CTYPE category (the default LC_CTYPE category is set from the LANG environment variable or by an explicit LC_CTYPE setting, but it can be overriden by the LC_ALL environment setting). If no locale setting is done in the enironment, the default locale will be C, for which the lowercase/uppercase conversion is based on the default character set of the system: this may convert only ASCII letters, or also ISO-8859-1 letters depending on the system...

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