PHP: strrpos - Manual

strrpos

kavih7 at yahoo dot com
08-Jun-2006 12:53


###################################################

#

# DESCRIPTION:

# This function returns the last occurance of a string,

# rather than the last occurance of a single character like

# strrpos does. It also supports an offset from where to

# start the searching in the haystack string.

#

# ARGS:

# $haystack (required) -- the string to search upon

# $needle (required) -- the string you are looking for

# $offset (optional) -- the offset to start from

#

# RETURN VALS:

# returns integer on success

# returns false on failure to find the string at all

#

###################################################



function strrpos_string($haystack, $needle, $offset = 0)

{

    if(trim($haystack) != "" && trim($needle) != "" && $offset <= strlen($haystack))

    {

        $last_pos = $offset;

        $found = false;

        while(($curr_pos = strpos($haystack, $needle, $last_pos)) !== false)

        {

            $found = true;

            $last_pos = $curr_pos + 1;

        }

        if($found)

        {

            return $last_pos - 1;

        }

        else

        {

            return false;

        }

    }

    else 

    {

        return false;

    }

}

shimon at schoolportal dot co dot il
03-May-2006 11:31


In strrstr function in php 4 there is also no offset.

<?

// by Shimon Doodkin

function chrrpos($haystack, $needle, $offset=false)

{

 $needle=$needle[0];

 $l=strlen($haystack);

 if($l==0)  return false;

 if($offset===false)  $offset=$l-1;

 else

 {

  if($offset>$l) $offset=$l-1;

  if($offset<0) return false;

 }

 for(;$offset>0;$offset--)

  if($haystack[$offset]==$needle)

   return $offset;

 return false;

}

?>

clan_ghw2 at hotmail dot com
02-Feb-2006 11:28


Brian below is incorrect about strrpos on different platforms.



Tested on Home PC (win32 + PHP 5.1.2) and Web Server (linux + 4.4.1)



echo strrpos("blah.blahannila","blaha");

returns 5 on windows

returns 5 on linux



Could've been a bug with an earlier PHP version, however the latest version of PHP returns position of the beginning of the string we're trying to find.



-Thaddeus

nh_handyman
22-Sep-2005 03:59


As noted in some examples below, strrpos does not act the same on every platform!



On Linux, it returns the position of the end of the target

On Windows, it returns the position of the start of the target



strrpos ("c:/somecity/html/t.php")



returns 11 on Windows

returns 16 on Linux



Brian

gordon at kanazawa-gu dot ac dot jp
13-Sep-2005 09:56


The "find-last-occurrence-of-a-string" functions suggested here do not allow for a starting offset, so here's one, tried and tested, that does:



function my_strrpos($haystack, $needle, $offset=0) {

    // same as strrpos, except $needle can be a string

    $strrpos = false;

    if (is_string($haystack) && is_string($needle) && is_numeric($offset)) {

        $strlen = strlen($haystack);

        $strpos = strpos(strrev(substr($haystack, $offset)), strrev($needle));

        if (is_numeric($strpos)) {

            $strrpos = $strlen - $strpos - strlen($needle);

        }

    }

    return $strrpos;

}

genetically altered mastermind at gmail
22-Aug-2005 10:30


Very handy to get a file extension:

$this->data['extension'] = substr($this->data['name'],strrpos($this->data['name'],'.')+1);

fab
10-Aug-2005 04:07


RE: hao2lian



There are a lot of alternative - and unfortunately buggy - implementations of strrpos() (or last_index_of as it was called) on this page. This one is a slight modifiaction of the one below, but it should world like a *real* strrpos(), because it returns false if there is no needle in the haystack.



<?php



function my_strrpos($haystack, $needle) {

   $index = strpos(strrev($haystack), strrev($needle));

   if($index === false) {

        return false;

   }

   $index = strlen($haystack) - strlen($needle) - $index;

   return $index;

}



?>

lwoods
06-Aug-2005 12:03


If you are a VBScript programmer ("ex-" of course), you will find that 'strrpos' doesn't work like the VBScript 'instrRev' function.



Here is the equivalent function:



VBScript:



k=instrrev(s,">",j);



PHP Equivalent of the above VBScript:



$k=strrpos(substr($s,0,$j),'>');



Comments:



You might think (I did!) that the following PHP function call would be the equivant of the above VBScript call:



$kk=strrpos($s,'>',$j);



NOPE!  In the above PHP call, $j defines the position in the string that should be considered the BEGINNING of the string, whereas in the VBScript call, j is to be considered the END of the string, as far as this search is concerned.  Anyway, the above 'strrpos' with the 'substr' will work.

(Probably faster to write a for loop!)

hao2lian
02-Aug-2005 07:50


Yet another correction on the last_index_of function algorithm:



function last_index_of($haystack, $needle) {

    $index = strpos(strrev($haystack), strrev($needle));

    $index = strlen($haystack) - strlen($needle) - $index;

    return $index;

}



"strlen(index)" in the most recent one should be "strlen($needle)".

jonas at jonasbjork dot net
06-Apr-2005 01:25


I needed to remove last directory from an path, and came up with this solution:



<?php



  $path_dir = "/my/sweet/home/";

  $path_up = substr( $path_dir, 0, strrpos( $path_dir, '/', -2 ) )."/";

  echo $path_up;



?>



Might be helpful for someone..

08-Mar-2005 11:14


In the below example, it should be substr, not strrpos.



<PHP?



$filename = substr($url, strrpos($url, '/') + 1);



?>

escii at hotmail dot com ( Brendan )
10-Jan-2005 07:12


I was immediatley pissed when i found the behaviour of strrpos ( shouldnt it be called charrpos ?) the way it is, so i made my own implement to search for strings.



<?

function proper_strrpos($haystack,$needle){

        while($ret = strrpos($haystack,$needle))

        {       

                if(strncmp(substr($haystack,$ret,strlen($needle)),

                                $needle,strlen($needle)) == 0 )

                        return $ret;

                $haystack = substr($haystack,0,$ret -1 );

        }

        return $ret;

}

?>

griffioen at justdesign dot nl
17-Nov-2004 10:57


If you wish to look for the last occurrence of a STRING in a string (instead of a single character) and don't have mb_strrpos working, try this:



    function lastIndexOf($haystack, $needle) {

        $index        = strpos(strrev($haystack), strrev($needle));

        $index        = strlen($haystack) - strlen(index) - $index;

        return $index;

    }

nexman at playoutloud dot net
07-Oct-2004 09:22


Function like the 5.0 version of strrpos for 4.x.

This will return the *last* occurence of a string within a string.



    function strepos($haystack, $needle, $offset=0) {        

        $pos_rule = ($offset<0)?strlen($haystack)+($offset-1):$offset;

        $last_pos = false; $first_run = true;

        do {

            $pos=strpos($haystack, $needle, (intval($last_pos)+(($first_run)?0:strlen($needle))));

            if ($pos!==false && (($offset<0 && $pos <= $pos_rule)||$offset >= 0)) {

                $last_pos = $pos;

            } else { break; }

            $first_run = false;

        } while ($pos !== false);

        if ($offset>0 && $last_pos<$pos_rule) { $last_pos = false; }

        return $last_pos;

    }



If my math is off, please feel free to correct.

  - A positive offset will be the minimum character index position of the first character allowed.

  - A negative offset will be subtracted from the total length and the position directly before will be the maximum index of the first character being searched.



returns the character index ( 0+ ) of the last occurence of the needle. 



* boolean FALSE will return no matches within the haystack, or outside boundries specified by the offset.

harlequin AT gmx DOT de
26-May-2004 09:59


this is my function for finding a filename in a URL:





<?php


    function getfname($url){


        $pos = strrpos($url, "/");


        if ($pos === false) {


            // not found / no filename in url...


            return false;


        } else {


            // Get the string length


            $len = strlen($url);


            if ($len < $pos){


                        print "$len / $pos";


                // the last slash we found belongs to http:// or it is the trailing slash of a URL


                return false;


            } else {


                $filename = substr($url, $pos+1, $len-$pos-1);


            }


        }


        return $filename;


    }


?>

tsa at medicine dot wisc dot edu
24-May-2004 05:17


What the heck, I thought I'd throw another function in the mix.  It's not pretty but the following function counts backwards from your starting point and tells you the last occurrance of a mixed char string:





<?php


function strrposmixed ($haystack, $needle, $start=0) {


   // init start as the end of the str if not set


   if($start == 0) {


       $start = strlen($haystack);


   }


   


   // searches backward from $start


   $currentStrPos=$start;


   $lastFoundPos=false;


   


   while($currentStrPos != 0) {


       if(!(strpos($haystack,$needle,$currentStrPos) === false)) {


           $lastFoundPos=strpos($haystack,$needle,$currentStrPos);


           break;


       }


       $currentStrPos--;


   }


   


   if($lastFoundPos === false) {


       return false;


   } else {


       return $lastFoundPos;


   }


}


?>

dreamclub2000 at hotmail dot com
04-Feb-2004 12:17


This function does what strrpos would if it handled multi-character strings:





<?php


function getLastStr($hay, $need){


  $getLastStr = 0;


  $pos = strpos($hay, $need);


  if (is_int ($pos)){ //this is to decide whether it is "false" or "0"


    while($pos) {


      $getLastStr = $getLastStr + $pos + strlen($need);


      $hay = substr ($hay , $pos + strlen($need));


      $pos = strpos($hay, $need);


    }


    return $getLastStr - strlen($need);


  } else {


    return -1; //if $need wasn�t found it returns "-1" , because it could return "0" if it�s found on position "0".


  }


}


?>

cagret at yahoo dot com
16-Dec-2003 09:12


This functions could be helpful:



<?php

/**

* @access public

* @package String

* @static

*/

class String {

    

    /**

    * Replace only the first occurence of the search string with the replacement string

    * @param string $string

    * @param string $search

    * @param string $replace

    * @return string

    * @access public

    */

    function replaceFirst($string, $search, $replace) {

        $pos = strpos($string, $search);

        if (is_int($pos)) {

            $len = strlen($search);

            return substr_replace($string, $replace, $pos, $len);

        }

        return $string;

    }

    

    /**

    * Replace only the last occurence of the search string with the replacement string

    * @param string $string

    * @param string $search

    * @param string $replace

    * @return string

    * @access public

    */

    function replaceLast($string, $search, $replace) {

        

        $pos = false;

        

        if (is_int(strpos($string, $search))) {

            $endPos = strlen($string);

            while ($endPos > 0) {

                $endPos = $endPos - 1;

                $pos = strpos($string, $search, $endPos);

                if (is_int($pos)) {

                    break;

                }

            } 

        }

        

        if (is_int($pos)) {

            $len = strlen($search);

            return substr_replace($string, $replace, $pos, $len);

        }

        

        return $string;

    }

}

?>

ZaraWebFX
14-Oct-2003 11:06


this could be, what derek mentioned:



<?

function cut_last_occurence($string,$cut_off) {

    return strrev(substr(strstr(strrev($string), strrev($cut_off)),strlen($cut_off)));

}    



//    example: cut off the last occurence of "limit"

    $str = "select delta_limit1, delta_limit2, delta_limit3 from table limit 1,7";

    $search = " limit";

    echo $str."\n";

    echo cut_last_occurence($str,"limit");

?>

lee at 5ss dot net
29-Aug-2003 07:21


I should have looked here first, but instead I wrote my own version of strrpos that supports searching for entire strings, rather than individual characters.  This is a recursive function.  I have not tested to see if it is more or less efficient than the others on the page.  I hope this helps someone!





<?php


//Find last occurance of needle in haystack


function str_rpos($haystack, $needle, $start = 0){


    $tempPos = strpos($haystack, $needle, $start);


    if($tempPos === false){


        if($start == 0){


            //Needle not in string at all


            return false;


        }else{


            //No more occurances found


            return $start - strlen($needle);


        }


    }else{


        //Find the next occurance


        return str_rpos($haystack, $needle, $tempPos + strlen($needle));


    }


}


?>

ara at bluemedia dot us
14-Jul-2003 01:09


derek@slashview.com notes a great replacement for strrpos because of the single character needle limitation in the strrpos function. He made a slight error in the code. He adds the length of the needle string instead of subtracting it from the final position. The function should be:





<?php


function strlastpos($haystack, $needle) {


# flip both strings around and search, then adjust position based on string lengths


return strlen($haystack) - strlen($needle) - strpos(strrev($haystack), strrev($needle));


}


?>

no_spammage_at_wwwcrm_dot_com
24-Apr-2003 08:07


This function does what strrpos would if it handled multi-character strings:





<?php


//function recurses until it finds last instance of $needle in $haystack





function getLastStr($haystack, $needle, $first_time=1){





                  $test=strstr($haystack, $needle);//is the needle there?


                  if ($test) return getLastStr($test, $needle, 0);//see if there is another one?


                  else if ($first_time) return false;//there is no occurence at all


                  else return $haystack;//that was the last occurence





                }


?>

FIE
15-Feb-2003 05:03


refering to the comment and function about lastIndexOf()...


It seemed not to work for me the only reason I could find was the haystack was reversed and the string wasnt therefore it returnt the length of the haystack rather than the position of the last needle... i rewrote it as fallows:





<?php


function strlpos($f_haystack,$f_needle) {


      $rev_str = strrev($f_needle);


      $rev_hay = strrev($f_haystack);


      $hay_len = strlen($f_haystack);


      $ned_pos = strpos($rev_hay,$rev_str);


      $result  = $hay_len - $ned_pos - strlen($rev_str);


      return $result;


}


?>





this one fallows the strpos syntax rather than java's lastIndexOf.


I'm not positive if it takes more resources assigning all of those variables in there but you can put it all in return if you want, i dont care if i crash my server ;).





~SILENT WIND OF DOOM WOOSH!

rob at pulpchat dot com
22-Jan-2003 02:23


For those of you coming from VBScript, I have 


converted the instrrev function to PHP:





<?php


function instrrev($n,$s) {


  $x=strpos(chr(0).strrev($n),$s)+0;


  return (($x==0) ? 0 : strlen($n)-$x+1);


}


?>





Remember that, unlike PHP and Javascript, VBScript 


returns 0 for no string found and 1 for the first 


character position, etc.





Hopefully this will save some time if you are 


converting ASP pages to PHP.

php dot net at insite-out dot com
17-Dec-2002 11:47


I was looking for the equivalent of Java's lastIndexOf(). I couldn't find it so I wrote this:





<?php


/*


Method to return the last occurrence of a substring within a 


string


*/


function last_index_of($sub_str,$instr) {


    if(strstr($instr,$sub_str)!="") {


        return(strlen($instr)-strpos(strrev($instr),$sub_str));


    }


    return(-1);


}


?>





It returns the numerical index of the substring you're searching for, or -1 if the substring doesn't exist within the string.

su.noseelg@naes, only backwards
13-Dec-2002 10:39


Maybe I'm the only one who's bothered by it, but it really bugs me when the last line in a paragraph is a single word. Here's an example to explain what I don't like:





The quick brown fox jumps over the lazy


dog.





So that's why I wrote this function. In any paragraph that contains more than 1 space (i.e., more than two words), it will replace the last space with '&nbsp;'.





<?php


function no_orphans($TheParagraph) {


    if (substr_count($TheParagraph," ") > 1) {


    $lastspace = strrpos($TheParagraph," ");


    $TheParagraph = substr_replace($TheParagraph,"&nbsp;",$lastspace,1);


    }


return $TheParagraph;


}


?>





So, it would change "The quick brown fox jumps over the lazy dog." to "The quick brown fox jumps over the lazy&nbsp;dog." That way, the last two words will always stay together.

DONT SPAM vardges at iqnest dot com
30-Oct-2002 01:22


that function can be modified to this





<?php


function strrpos_str ($string, $searchFor, $startFrom = 0)


{


    $addLen = strlen ($searchFor);


    $endPos = $startFrom - $addLen;





    while (true)


    {


        if (($newPos = strpos ($string, $searchFor, $endPos + $addLen)) === false) break;


        $endPos = $newPos;


    }





    return ($endPos >= 0) ? $endPos : false;


}





// example


$str = "abcabcabc";


$search = "ab";





$pos = strrpos_str ($str, $search);


if ($pos === false) echo "not found";


else echo $pos; // returns 6 in this case


?>

28-May-2002 12:46


Cause:


Find position of last occurrence of a string in a string... 


and I needed it, I hacked a little code to do this:





Maybe it is helpful for you.





<?php


 function _strrpos_needle($sourcestring,$needle){





    /* just for easier understanding */


    $tempString=$sourcestring;





    do {


      $tempPos=strpos($tempString,$needle);


      $tempString=substr($tempString,$tempPos+strlen($needle));


      $realPos=$realPos+$tempPos;


    } while (!is_bool($tempPos));





    return $realPos;





  }


?>

derek at slashview dot com
01-Feb-2002 04:06


To find the position of the start of the last occurence of a string, we can do this:

$pos=strlen($haystack) - (strpos(strrev($haystack), strrev($needle)) + strlen($needle));

The idea is to reverse both $needle and $haystack, use strpos to find the first occurence of $needle in $haystack, then count backwards by the length of $needle. Finally, subtract $pos from length of $haystack. A lot easier to figure out if you use a test string to visualize it.  :)

strrpos

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