strnatcasecmp

stristr

Last updated: Fri, 30 Oct 2009

strlen

(PHP 4, PHP 5)

strlen — Get string length

Description

int strlen ( string $string )

Returns the length of the given string .

Parameters

string: The string being measured for length.

Return Values

The length of the string on success, and 0 if the string is empty.

Examples

Example #1 A strlen() example


<?php
$str = 'abcdef';
echo strlen($str); // 6

$str = ' ab cd ';
echo strlen($str); // 7
?>


It seems to me that all strings in PHP are ASCII, this is fine for some but for me I need more. I thought I would show off a small function that I made that will tell you the length of a UTF-8 string. This comes in handy if you want to restrict the size of user input to say 30 chars - but don't want to force ascii only input on your users.



<?php

function utf8_strlen($str)

    {

    $count = 0;



    for($i = 0; $i < strlen($str); $i++)

        {

        $value = ord($str[$i]);

        if($value > 127)

            {

            if($value >= 192 && $value <= 223)

                $i++;

            elseif($value >= 224 && $value <= 239)

                $i = $i + 2;

            elseif($value >= 240 && $value <= 247)

                $i = $i + 3;

            else

                die('Not a UTF-8 compatible string');

            }

       

        $count++;

        }

   

    return $count;

    }

?>

Amaroq
20-Mar-2009 07:51


When dealing with submitted forms that you've imposed a character limit on, you must remember that functions that count characters consider "\r\n" to be two characters.



<?php

//These will both output 2.

echo strlen("\r\n");

echo mb_strlen("\r\n");

?>



If I had thought of this starting out, I would have saved myself several hours of trouble trying to get php to cut a message to the same length that my auxiliary javascript validation imposed on it.

Anonymous
16-Feb-2009 05:51


simple speed test for UTF-8 strings:



<?php



header("Content-type: text/html; charset=UTF-8");

ini_set('mbstring.internal_encoding', 'UTF-8');



?><pre><?



function utf8_strlen($s) {

    $c = strlen($s); $l = 0;

    for ($i = 0; $i < $c; ++$i) if ((ord($s[$i]) & 0xC0) != 0x80) ++$l;

    return $l;

}



function utf0_strlen($s) {

    $l = 0; $i = 0;

    while ($n = ord($s[$i++])) if (($n & 0xC0) != 0x80) ++$l;

    return $l;

}



function utfs_strlen($s) {

    $c = strlen($s);

    $l = 0;

    for($i = 0; $i < $c; $i++) {

        $v = ord($s[$i]);

        if($v > 127) {

            if($v >= 192 && $v <= 223) ++$i;

            elseif($v >= 224 && $v <= 239) $i += 2;

            elseif($v >= 240 && $v <= 247) $i += 3;

            else die('Not a UTF-8 compatible string');

        }

        ++$l;

    }

    return $l;

} 



function spl_strlen($s) {

  return count(preg_split("//u", $s)) - 2;

}



function dcd_strlen($s) {

    return strlen(utf8_decode($s));

} 



function preg_strlen($s) {

  return preg_match_all('/[\x00-\x7F\xC0-\xFD]/', $s, $d);

}



$src = '=123! !ы"в#$%&\'()*+,—./:;<=>?@[\]^_`{|}~'.

    '    йцукенгшщзхъфывапролджтьбю'.chr(0).'ы';



$tc = 10000; //test count



$l = mb_strlen($src, 'UTF-8'); //real testing string length



$lst = array('strlen', 'mb_strlen', 'dcd_strlen',

    'preg_strlen', 'utfs_strlen', 'utf8_strlen',

    'utf0_strlen', 'spl_strlen'); // list of functions



foreach ($lst as $f) {

    $t = microtime(1);

    for($i = 0; $i < $tc; $i++) $f($src);

    $t = microtime(1) - $t;

    printf("%14s : %0.6f : %03u%s\n", 

        $f, $t, $q = $f($src), $q != $l ? ' - failed!' : '');

}

?></pre>



main results:

        strlen : 0.009419 : 112 failed!

     mb_strlen : 0.016377 : 075

    dcd_strlen : 0.063055 : 075

   preg_strlen : 1.106809 : 075

   utfs_strlen : 1.701586 : 075

   utf8_strlen : 2.321344 : 075

   utf0_strlen : 2.578518 : 073 failed!

    spl_strlen : 3.789029 : 075

jonathan dot protzenko at gmail dot com
23-Aug-2008 02:35


paolo dot mosna at gmail dot com's solution for getting the length of a unicode string didn't work for me. Instead, I used the following dirty function (which can be surely improved, but I'm giving the idea) :



<?php

function ustrlen($s) {

  $a = preg_split("//u", $s);

  $i = -2;

  foreach ($a as $b)

    $i++;

  return $i;

}

?>



This will return the correct length for any unicode string.

radu_keepwalking at yahoo dot com
15-Apr-2008 11:37


Another way to preview a text with or without html tags, and end not cut in a middle of a word.



<?php

function preview_text($TEXT, $LIMIT, $TAGS = 0) {



    // TRIM TEXT

    $TEXT = trim($TEXT);



    // STRIP TAGS IF PREVIEW IS WITHOUT HTML

    if ($TAGS == 0) $TEXT = preg_replace('/\s\s+/', ' ', strip_tags($TEXT));



    // IF STRLEN IS SMALLER THAN LIMIT RETURN

    if (strlen($TEXT) < $LIMIT) return $TEXT;



    if ($TAGS == 0) return substr($TEXT, 0, $LIMIT) . " ...";

    else {



        $COUNTER = 0;

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



            if ($TEXT{$i} == "<") $STOP = 1;



            if ($STOP != 1) {



                $COUNTER++;

            }



            if ($TEXT{$i} == ">") $STOP = 0;

            $RETURN .= $TEXT{$i};



            if ($COUNTER >= $LIMIT && $TEXT{$i} == " ") break;



        }



        return $RETURN . "...";

    }



}

?>

mail4adry at inwind dot it
21-Aug-2007 08:53


This can be useful to put a preview of an article on the front page when the rest of the article is displayed on another page:





<?php


function getPreviewText($text) {


    // Strip all tags


    $desc = strip_tags(html_entity_decode($text), "<a><em>");


    $charlen = 0; $crs = 0;


    if(strlen_HTML($desc) == 0)


        $preview = substr($desc, 0, 69);


    else


    {


        $i = 0;


        while($charlen < 80)


        {


            $crs = strpos($desc, " ", $crs)+1;


            $lastopen = strrpos(substr($desc, 0, $crs), "<");


            $lastclose = strrpos(substr($desc, 0, $crs), ">");


            if($lastclose > $lastopen)


            {


                // we are not in a tag


                $preview = substr($desc, 0, $crs);


                $charlen = strlen_noHTML($preview);


            }


            $i++;


        }


    }


    return $preview."&#8230;"


}


?>





will display text cut as near as possible to character 80 respecting each <a> and <em> tags and ending with ...

mail4adry at inwind dot it
21-Aug-2007 04:28


<?php


/**


 * return length of a string regardeless of html tags in it


 *


 * @param string $html


 * @return string


 */


function strlen_noHtml($string){


    $crs = 0;


    $charlen = 0;


    $len = strlen($string);


    while($crs < $len)


    {


        $offset = $crs;


        $crs = strpos($string, "<", $offset);


        if($crs === false)


        {


           $crs = $len;


           $charlen += $crs - $offset;


        }


        else


        {


            $charlen += $crs - $offset;


            $crs = strpos($string, ">", $crs)+1;


        }


    }


    return $charlen;


}





/**


 * return length of a string regarding html tags in it


 *


 * @param string $html


 * @return string


 */


function strlen_Html($string){


    $crs = 0;


    $charlen = 0;


    $len = strlen($string);


    while($crs < $len)


    {


        $scrs = strpos($string, "<", $crs);


        if($scrs === false)


        {


           $crs = $len;


        }


        else


        {


            $crs = strpos($string, ">", $scrs)+1;


            if($crs === false)


                $crs = $len;


            $charlen += $crs - $scrs;


        }


    }


    return $charlen;


}


?>





Example:





<?php


$text = "<p>Test 'a' paragraph.</p><!-- Comment --> Other text";





echo "strlen without HTML chars:".strlen_noHtml($text);


echo "<br>";


echo "strlen of HTML chars:".strlen_html($text);


?>





Will output:


strlen without HTML chars:30


strlen of HTML chars:23

bradmwalker at cableone dot net
01-Jul-2007 10:48


want a predicate that tests a string for emptiness? use strlen instead of empty(). strlen only returns a false-equivalent value for ''.





example:





<?php


// takes string_array and returns an array without any values w/empty strings


function filter_empties ($string_array) {


    // note: the immensely retarded empty() function returns true on string '0'


    // use strlen as empty string predicate


    return count($string_array) ? array_filter ($string_array, 'strlen') : $string_array;


}


?>

topera at gmail dot com
27-Jun-2007 03:32


<?php


//------------------------------------------


// This function returns the necessary


// size to show some string in display


// For example:


// $a = strlen_layout("WWW"); // 49


// $a = strlen_layout("..."); // 16


// $a = strlen_layout("Hello World"); // 99


//------------------------------------------


function strlen_pixels($text) {


    /*


        Pixels utilized by each char (Verdana, 10px, non-bold)


        04: j


        05: I\il,-./:; <espace>


        06: J[]f()


        07: t


        08: _rz*


        09: ?csvxy


        10: Saeko0123456789$


        11: FKLPTXYZbdghnpqu


        12: AÇBCERV


        13: <=DGHNOQU^+


        14: w


        15: m


        16: @MW


    */





    // CREATING ARRAY $ps ('pixel size')


    // Note 1: each key of array $ps is the ascii code of the char.


    // Note 2: using $ps as GLOBAL can be a good idea, increase speed


    // keys:    ascii-code


    // values:  pixel size





    // $t: array of arrays, temporary


    $t[] = array_combine(array(106), array_fill(0, 1, 4));





    $t[] = array_combine(array(73,92,105,108,44), array_fill(0, 5, 5));


    $t[] = array_combine(array(45,46,47,58,59,32), array_fill(0, 6, 5));


    $t[] = array_combine(array(74,91,93,102,40,41), array_fill(0, 6, 6));


    $t[] = array_combine(array(116), array_fill(0, 1, 7));


    $t[] = array_combine(array(95,114,122,42), array_fill(0, 4, 8));


    $t[] = array_combine(array(63,99,115,118,120,121), array_fill(0, 6, 9));


    $t[] = array_combine(array(83,97,101,107), array_fill(0, 4, 10));


    $t[] = array_combine(array(111,48,49,50), array_fill(0, 4, 10));


    $t[] = array_combine(array(51,52,53,54,55,56,57,36), array_fill(0, 8, 10));


    $t[] = array_combine(array(70,75,76,80), array_fill(0, 4, 11));


    $t[] = array_combine(array(84,88,89,90,98), array_fill(0, 5, 11));


    $t[] = array_combine(array(100,103,104), array_fill(0, 3, 11));


    $t[] = array_combine(array(110,112,113,117), array_fill(0, 4, 11));


    $t[] = array_combine(array(65,195,135,66), array_fill(0, 4, 12));


    $t[] = array_combine(array(67,69,82,86), array_fill(0, 4, 12));


    $t[] = array_combine(array(78,79,81,85,94,43), array_fill(0, 6, 13));


    $t[] = array_combine(array(60,61,68,71,72), array_fill(0, 5, 13));


    $t[] = array_combine(array(119), array_fill(0, 1, 14));


    $t[] = array_combine(array(109), array_fill(0, 1, 15));


    $t[] = array_combine(array(64,77,87), array_fill(0, 3, 16));   


   


    // merge all temp arrays into $ps


    $ps = array();


    foreach($t as $sub) $ps = $ps + $sub;


   


    // USING ARRAY $ps


    $total = 1;


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


        $temp = $ps[ord($text[$i])];


        if (!$temp) $temp = 10.5; // default size for 10px


        $total += $temp;


    }


    return $total;


}


?>





Rafael Pereira dos Santos

paolo dot mosna at gmail dot com
10-Jan-2007 03:58


Title: Strlen() ant bytes string lenght.


Just to remember that strlen() return the number of characters of a string. Often the strlen() function is used to compute the length in bytes of a string. This is correct until string is single byte encoded. If multi-byte char-set is used this constraint i no more verified. So when you require the number of bytes of a ASCII or UTF-8 encoded string, it is better to use following function:





<?php


    /**


     * Count the number of bytes of a given string.


     * Input string is expected to be ASCII or UTF-8 encoded.


     * Warning: the function doesn't return the number of chars


     * in the string, but the number of bytes.


     *


     * @param string $str The string to compute number of bytes


     *


     * @return The length in bytes of the given string.


     */


    function strBytes($str)


    {


      // STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT


      


      // Number of characters in string


      $strlen_var = strlen($str);


  


      // string bytes counter


      $d = 0;


      


     /*


      * Iterate over every character in the string,


      * escaping with a slash or encoding to UTF-8 where necessary


      */


      for ($c = 0; $c < $strlen_var; ++$c) {


          


          $ord_var_c = ord($str{$d});


          


          switch (true) {


              case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):


                  // characters U-00000000 - U-0000007F (same as ASCII)


                  $d++;


                  break;


              


              case (($ord_var_c & 0xE0) == 0xC0):


                  // characters U-00000080 - U-000007FF, mask 110XXXXX


                  // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8


                  $d+=2;


                  break;


  


              case (($ord_var_c & 0xF0) == 0xE0):


                  // characters U-00000800 - U-0000FFFF, mask 1110XXXX


                  // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8


                  $d+=3;


                  break;


  


              case (($ord_var_c & 0xF8) == 0xF0):


                  // characters U-00010000 - U-001FFFFF, mask 11110XXX


                  // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8


                  $d+=4;


                  break;


  


              case (($ord_var_c & 0xFC) == 0xF8):


                  // characters U-00200000 - U-03FFFFFF, mask 111110XX


                  // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8


                  $d+=5;


                  break;


  


              case (($ord_var_c & 0xFE) == 0xFC):


                  // characters U-04000000 - U-7FFFFFFF, mask 1111110X


                  // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8


                  $d+=6;


                  break;


              default:


                $d++;    


          }


      }


      


      return $d;


    }


?>





This function has been adapted form the JSON function used to convert character in UTF-8 representation.





With this new function we solved problem in JSON and in PEAR/SOAP php libraries.

liquix at hjelpesentral dot no
17-Aug-2006 12:57


An easy function to make sure the words in a sentence is not above the maximum lengt of characters. This is used to prevent that users posting for an example comments on your page and drag the page width out.



Returns true or false

<?php

function wordlength($txt, $limit)

{

   $words = explode(' ', $txt);



   foreach($words as $v)

   {

       if(strlen($v) > $limit)

       {

            return false;

       }

   }



   return true;

}

?>



Uses like this:

<?php



$txt = "Onelongword and some small ones";



if(!wordlength($txt, 10))

{

    die("One of the words where too long");

}



?>



That will return false since one of the words in $txt is too long. (Maximum set to 10)

Hage Yaapa
12-Jan-2006 11:51


Sometimes you really wanna make sure no user edits the 'maxlength' attribute of the HTML page and POSTs a 5 Mb string to your script. Probably, advanced programmers already take precautions, this one is just a very simple tip for beginners on how to check the character lenth of the POST variables in an effective manner.



<?php



// ALWAYS clean the POST variables of any HTML tags first.

// And here we do it in one easy step.

 $_POST = array_map('strip_tags', $_POST);

 

// These are the POST variables in the example

 $alias = $_POST['alias'];

 $name = $_POST['name'];

 $status = $_POST['status'];

 $year = $_POST['year'];

 

// We create an array that contains the expected character length

// for each POST variable

 $exlen = array (

      'alias'=>12,

      'name'=>30,

      'status'=>10,

      'year'=>4

);

 

// Now check if any of them exceeds the expected length

 foreach ($exlen as $key=>$val) {

      if (strlen($$key) > $val) {

            // The user has definitely edited the HTML! He has a lot of time, could be bad.

          // This section can edited according to your needs - very simple to complex.

          // Log the event or send an e-mail to the admin at the basic.

          // However, in this example we just print a warning.    

          print 'WARNING: The FBI is looking for you, dude!';

          exit;

          // The best part is that the script won't look for any other 

          // POST variables other than the ones which we are expecting already.

      }

}

?>



Similarly, with the use of Regular Expressions you could check the data type and string format too.

bartek at proteus,pl
19-Jul-2005 12:08


> Just a precisation, maybe obvious, about the strlen() behaviour: 


> with binary strings (i.e. returned by the pack() finction) is made 


> a byte count... so strlen returns the number of bytes contained 


> in the binary string.





This is not always true. strlen() might be shadowed by mb_strlen().


If that is the case it might treat binary data as unocode string and return wrong value (I just found it out after fighting with egroupware email attachment handling bug).





So, if your data is binary I would suggest using somthing like this (parts of the code from egroupware):





<?php


$has_mbstring = extension_loaded('mbstring') ||@dl(PHP_SHLIB_PREFIX.'mbstring.'.PHP_SHLIB_SUFFIX);


$has_mb_shadow = (int) ini_get('mbstring.func_overload');





if ($has_mbstring && ($has_mb_shadow & 2) ) {


   $size = mb_strlen($this->output_data,'latin1');


} else { 


   $size = strlen($this->output_data);


}


?>


-- 


Bartek

triadsebas at triads dot buildtolearn dot net
17-Jul-2005 12:49


A nice use of the strlen() function, the following function will check if one of the words in $input is longer than $maxlenght,  $maxlenght is standard 40.

<?php

function check_input($input, $maxlenght= 40)

$temp_array = explode(" ", $input);

foreach ($temp_array as $word) {

if (strlen($word) > $maxlenght) {

return false;

}

}

return true;

} 

?>

Example:

<?php

if (!check_input($_POST['message'])) {

print 'One of your words in your message in longer than 40 chars. Please edit your message.';

}

?>

http://nsk.wikinerds.org
22-Apr-2005 04:02


Beware: strlen() counts new line characters at the end of a string, too!





<?php


  $a = "123\n";


  echo "<p>".strlen($a)."</p>";


?>





The above code will output 4.

packe100 at hotmail dot com
14-Mar-2005 03:07


Just a precisation, maybe obvious, about the strlen() behaviour: with binary strings (i.e. returned by the pack() finction) is made a byte count... so strlen returns the number of bytes contained in the binary string.

php at capcarrere dot org
06-Feb-2005 02:32


Hi, 





if you want to trim a sentence to a certain number of 


characters so that it is displayed nicely in a HTML page 


(in a table for instance), then you actually want to count


the number of characters displayed rather than the 


actual number of characters of the string. 





For instance:


"L&agrave; bas" should really be 5 character long, 


rather than 10.





Also you don't want to cut a special char in the middle. 


For instance:


If 3 is the maximum number of characters, 





"L&agrave; bas"  should be cut as "L&agrave; ..." 


and not "L&a...";





So here is a simple method to dothat:





<?php


function nicetrim ($s) {


// limit the length of the given string to $MAX_LENGTH char


// If it is more, it keeps the first $MAX_LENGTH-3 characters 


// and adds "..."


// It counts HTML char such as &aacute; as 1 char.


//





  $MAX_LENGTH = 22;


  $str_to_count = html_entity_decode($s);


  if (strlen($str_to_count) <= $MAX_LENGTH) {


    return $s;


  }





  $s2 = substr($str_to_count, 0, $MAX_LENGTH - 3);


  $s2 .= "...";


  return htmlentities($s2);


}


?>

Patrick(a)Bierans()de
29-Nov-2004 11:24


<?php


function array_strlen(&$array,$fuse=200,$depth=0)


{


  // returns the strlen of all elements in a given array, an array inside


  // an array will add another 8 points





  // fuse: Recursion is limited to 200 calls, if you want unlimited calls


  //       use fuse=0 - warning: if an array element contains a reference


  //       to the array itself it will run endless if fuse set to 0 or below.





  $strlen=0;


  $fuse-=1;


  if ($fuse==0) return $strlen;





  if (is_array($array))


  {


    if ($depth>0) $strlen+=8;


    reset($array);


    $depth+=1;


    foreach ($array as $sub) $strlen+=array_strlen($sub,$fuse,$depth);


  }


  else


  {


    $strlen+=strlen($array);


  }


  return $strlen;


} // array_strlen()


?>

chernyshevsky at hotmail dot com
05-Sep-2004 10:36


The easiest way to determine the character count of a UTF8 string is to pass the text through utf8_decode() first:





<?php


$length = strlen(utf8_decode($s));


?>





utf8_decode() converts characters that are not in ISO-8859-1 to '?', which, for the purpose of counting, is quite alright.

dtorop932 at hotmail dot com
03-Dec-2003 10:25


To follow up on dr-strange's utf8_strlen(), here are two succinct alternate versions.  The first is slower for multibyte UTF-8, faster for single byte UTF-8.  The second should be much faster for all but very brief strings, and can easily live inline in code.  Neither validates the UTF-8.



Note that the right solution is to use mb_strlen() from the mbstring module, if one is lucky enough to have that compiled in...



<?php

// choice 1

function utf8_strlen($str) {

  $count = 0;

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

    if ((ord($str[$i]) & 0xC0) != 0x80) {

      ++$count;

    }

  }

  return $count;

}



// choice 2

function utf8_strlen($str) {

  return preg_match_all('/[\x00-\x7F\xC0-\xFD]/', $str, $dummy);

}

?>

Patrick
01-Aug-2003 09:36


Just a general pointer that I have hit upon after some struggle:



Most blobs can easily be treated as strings, so to retreat info on a blob or to manipulate it in any way, I recommend trying out string-related functions first. They've worked well for me.

suchy at ecl dot pl
13-May-2003 10:22


a little modification of rasmus solution





<?php


$tmp=0; $s="blah"; 


while($c=$s[$tmp++]) { echo $c; } 


?>





but what happens when the string contains zeros?





<?php $s="blah0blah"; ?>


the script stops....





here is sample of code and the string is correcly parsed using strlen() even when containing zeros:





<?php


$s="blah0blah";


$si=0;


$s_len=strlen($s);


for ($si=0;$si<$s_len;$si++)


{


 $c=$s[$si];


 echo $c;


}


?>

dr - strange at shaw dot ca
03-Oct-2002 02:08


It seems to me that all strings in PHP are ASCII, this is fine for some but for me I need more. I thought I would show off a small function that I made that will tell you the length of a UTF-8 string. This comes in handy if you want to restrict the size of user input to say 30 chars - but don't want to force ascii only input on your users.





<?php


function utf8_strlen($str)


    {


    $count = 0;





    for($i = 0; $i < strlen($str); $i++)


        {


        $value = ord($str[$i]);


        if($value > 127)


            {


            if($value >= 192 && $value <= 223)


                $i++;


            elseif($value >= 224 && $value <= 239)


                $i = $i + 2;


            elseif($value >= 240 && $value <= 247)


                $i = $i + 3;


            else


                die('Not a UTF-8 compatible string');


            }


        


        $count++;


        }


    


    return $count;


    }


?>

26-May-2001 07:11


Note that PHP does not need to traverse the string to know its length with strlen(). The length is an attribute of the array used to store the characters. Do not count on strings being terminated by a NULL character. This may not work with some character encodings, and PHP strings are binary-safe !


PHP4 included a NULL character after the last position in the string, however, this does not change the behavior of strlen or the binary safety: this NULL character is not stored.





However PHP4 allows now to reference the position after the end of the string for both read and write access:





* when reading at that position (e.g. $s[strlen($s)]), you get a warning with PHP3, and you'll get 0 with PHP4 not returning a warning.





* you can assign it directly in PHP4 with one character to increase the string length by one character:





<?php


$s[strlen($s)]=65; //append 'A'


$s[]=65; //append 'A'


$s[strlen($s)]=0; //append NUL (stored!)


$s[]=0; //append NUL (stored!)


?>





Such code did not work in PHP3, where the only way to extend the string length was by using a concat operator.





However, reading or writing past the end of the string, using an array index superior to the current string length will still raise a warning in PHP4.

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