strrpos

(PHP 4, PHP 5)

strrposEncontra a posição da última ocorrência de um caractere em uma string

Descrição

int strrpos ( string $haystack , string $needle [, int $offset ] )

Retorna a posição numérica da última ocorrência de needle na string haystack. Note que a needle neste caso pode apenas ser um simples caractere PHP 4. Se uma string é passada como a needle, então apenas o primeiro caractere dessa string será usado.

Se needle não é encontrado, retorna FALSE.

É fácil errar a interpretação dos valores de retorno para "character found at position 0" e "character not found". Aqui segue um exemplo de como detectar a diferença:

<?php

// no PHP 4.0.0 e posterior:
$pos strrpos($mystring"b");
if (
$pos === false) { // note: três sinais iguais
    // não encontrado...
}

// em versões mais antigas do que 4.0.0:
$pos strrpos($mystring"b");
if (
is_bool($pos) && !$pos) {
    
// não encontrado...
}
?>

Se needle não é uma string, ela é convertida para um inteiro e aplicada como o valor ordinal de um caractere.

Nota: No PHP 5.0.0 o offset pode ser especificado para iniciar a busca num número arbitrário de caracteres dentro da string. Valores negativos irão parar a busca em um ponto arbitrário antes do final da string.

Nota: A needle pode ser uma string de mais de um caractere no PHP 5.

Parâmetros

haystack

needle

offset

Valor Retornado

Veja Também

  • strpos() - Encontra a posição da primeira ocorrência de uma string
  • strripos() - Encontra a posição da última ocorrência de uma string case-insensitive em uma string
  • strrchr() - Encontra a ultima ocorrência de um caractere em uma string
  • substr() - Retorna uma parte de uma string
  • stristr() - strstr sem diferenciar maiúsculas e minúsculas
  • strstr() - Encontra a primeira ocorrencia de uma string

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User Contributed Notes 28 notes

up
5
arlaud pierre
1 year ago
This seems to behave like the exact equivalent to the PHP 5 offset parameter for a PHP 4 version.

<?php
 
function strrpos_handmade($haystack, $needle, $offset = 0){

  if(
$offset === 0) return strrpos($haystack, $needle);
 
 
$length = strlen($haystack);
 
$size = strlen($needle);

  if(
$offset < 0) {
   
$virtual_cut = $length+$offset;
   
$haystack = substr($haystack, 0, $virtual_cut+$size);
   
$ret = strrpos($haystack, $needle);
    return
$ret > $virtual_cut ? false : $ret;
  } else {
   
$haystack = substr($haystack, $offset);
   
$ret = strrpos($haystack, $needle);
    return
$ret === false ? $ret : $ret+$offset;
  }

}
?>
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4
dmitry dot polushkin at gmail dot com
7 years ago
Returns the filename's string extension, else if no extension found returns false.
Example: filename_extension('some_file.mp3'); // mp3
Faster than the pathinfo() analogue in two times.
<?php
function filename_extension($filename) {
   
$pos = strrpos($filename, '.');
    if(
$pos===false) {
        return
false;
    } else {
        return
substr($filename, $pos+1);
    }
}
?>
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3
escii at hotmail dot com ( Brendan )
9 years ago
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;
}
?>
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3
Daniel Brinca
6 years ago
Here is a simple function to find the position of the next occurrence of needle in haystack, but searching backwards  (lastIndexOf type function):

//search backwards for needle in haystack, and return its position
function rstrpos ($haystack, $needle, $offset){
    $size = strlen ($haystack);
    $pos = strpos (strrev($haystack), $needle, $size - $offset);
   
    if ($pos === false)
        return false;
   
    return $size - $pos;
}

Note: supports full strings as needle
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3
brian at enchanter dot net
6 years ago
The documentation for 'offset' is misleading.

It says, "offset may be specified to begin searching an arbitrary number of characters into the string. Negative values will stop searching at an arbitrary point prior to the end of the string."

This is confusing if you think of strrpos as starting at the end of the string and working backwards.

A better way to think of offset is:

- If offset is positive, then strrpos only operates on the part of the string from offset to the end. This will usually have the same results as not specifying an offset, unless the only occurences of needle are before offset (in which case specifying the offset won't find the needle).

- If offset is negative, then strrpos only operates on that many characters at the end of the string. If the needle is farther away from the end of the string, it won't be found.

If, for example, you want to find the last space in a string before the 50th character, you'll need to do something like this:

strrpos($text, " ", -(strlen($text) - 50));

If instead you used strrpos($text, " ", 50), then you would find the last space between the 50th character and the end of the string, which may not have been what you were intending.
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2
kavih7 at yahoo dot com
7 years ago
<?php
###################################################
#
# 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;
    }
}
?>
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2
su.noseelg@naes, only backwards
11 years ago
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.
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1
shimon at schoolportal dot co dot il
7 years ago
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;
}
?>
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1
ZaraWebFX
10 years ago
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");
?>
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0
alexandre at NOSPAM dot pixeline dot be
5 years ago
I needed to check if a variable that contains a generated folder name based on user input had a trailing slash.

This did the trick:

<?php
   
// Detect and remove a trailing slash
   
$root_folder = ((strrpos($root_folder, '/') + 1) == strlen($root_folder)) ? substr($root_folder, 0, - 1) : $root_folder;
?>
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0
dixonmd at gmail dot com
6 years ago
<?php
        $pos
= strlen(string $haystack) - strpos (strrev(string $haystack), strrev(string $needle)) - strlen(string $needle);
?>

         If in the needle there is more than one character then in php 4 we can use the above statement for finding the position of last occurrence of a substring in a string instead of strrpos. Because in php 4 strrpos uses the first character of the substring.

eg :
<?php
        $haystack
= "you you you you you";
       
$needle = "you";
       
$pos1 = strlen($haystack) - strpos (strrev($haystack), strrev($needle)) - strlen($needle);
        echo
$pos1 . "<br>";
       
$pos2 strrpos($haystack, $needle);
        echo
$pos2 . "<br>";
?>
up
0
pb at tdcspace dot dk
6 years ago
what the hell are you all doing. Wanna find the *next* last from a specific position because strrpos is useless with the "offset" option, then....

ex: find 'Z' in $str from position $p,  backward...

while($p > -1 and $str{$p} <> 'Z') $p--;

Anyone will notice $p = -1 means: *not found* and that you must ensure a valid start offset in $p, that is >=0 and < string length. Doh
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0
jafet at g dot m dot a dot i dot l dot com
7 years ago
Full strpos() functionality, by yours truly.

<?php
function conforming_strrpos($haystack, $needle, $offset = 0)
{
   
# Why does strpos() do this? Anyway...
   
if(!is_string($needle)) $needle = ord(intval($needle));
   
$haystack = strval($haystack);
   
# Parameters
   
$hlen = strlen($haystack);
   
$nlen = strlen($needle);
   
# Come on, this is a feature too
   
if($nlen == 0)
    {
       
trigger_error(__FUNCTION__.'(): Empty delimiter.', E_USER_WARNING);
        return
false;
    }
   
$offset = intval($offset);
   
$hrev = strrev($haystack);
   
$nrev = strrev($needle);
   
# Search
   
$pos = strpos($hrev, $nrev, $offset);
    if(
$pos === false) return false;
    else return
$hlen - $nlen - $pos;
}
?>

Note that $offset is evaluated from the end of the string.

Also note that conforming_strrpos() performs some five times slower than strpos(). Just a thought.
up
0
mijsoot_at_gmail_dot_com
7 years ago
To begin, i'm sorry for my English.
So, I needed of one function which gives me the front last position of a character.
Then I said myself that it should be better to make one which gives the "N" last position.

$return_context = "1173120681_0__0_0_Mijsoot_Thierry";

// Here i need to find = "Mijsoot_Thierry"

//echo $return_context."<br />";// -- DEBUG

function findPos($haystack,$needle,$position){
    $pos = strrpos($haystack, $needle);
    if($position>1){
        $position --;
        $haystack = substr($haystack, 0, $pos);
        $pos = findPos($haystack,$needle,$position);
    }else{
        // echo $haystack."<br />"; // -- DEBUG
        return $pos;
    }
    return $pos;
}

var_dump(findPos($return_context,"_",2)); // -- TEST
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0
Christ Off
7 years ago
Function to truncate a string
Removing dot and comma
Adding ... only if a is character found

function TruncateString($phrase, $longueurMax = 150) {
    $phrase = substr(trim($phrase), 0, $longueurMax);
    $pos = strrpos($phrase, " ");
    $phrase = substr($phrase, 0, $pos);
    if ((substr($phrase,-1,1) == ",") or (substr($phrase,-1,1) == ".")) {
        $phrase = substr($phrase,0,-1);
    }
    if ($pos === false) {
        $phrase = $phrase;
    }
    else {
        $phrase = $phrase . "...";
    }
return $phrase;
}
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0
php NO at SPAMMERS willfris SREMMAPS dot ON nl
7 years ago
<?php
/*******
 ** Maybe the shortest code to find the last occurence of a string, even in php4
 *******/
function stringrpos($haystack,$needle,$offset=NULL)
{
    return
strlen($haystack)
           -
strpos( strrev($haystack) , strrev($needle) , $offset)
           -
strlen($needle);
}
// @return   ->   chopped up for readability.
?>
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0
purpleidea
7 years ago
I was having some issues when I moved my code to run it on a different server.
The earlier php version didn't support more than one character needles, so tada, bugs. It's in the docs, i'm just pointing it out in case you're scratching your head for a while.
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0
gordon at kanazawa-gu dot ac dot jp
8 years ago
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;
}
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0
genetically altered mastermind at gmail
8 years ago
Very handy to get a file extension:
$this->data['extension'] = substr($this->data['name'],strrpos($this->data['name'],'.')+1);
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0
fab
8 years ago
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;
}

?>
up
0
jonas at jonasbjork dot net
9 years ago
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..
up
0
griffioen at justdesign dot nl
9 years ago
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;
    }
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0
nexman at playoutloud dot net
9 years ago
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.
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0
tsa at medicine dot wisc dot edu
9 years ago
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;
   }
}
?>
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0
lee at 5ss dot net
10 years ago
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));
    }
}
?>
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0
FIE
11 years ago
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!
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0
php dot net at insite-out dot com
11 years ago
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.
up
-1
maxmike at gmail dot com
4 years ago
I've got a simple method of performing a reverse strpos which may be of use.  This version I have treats the offset very simply:
Positive offsets search backwards from the supplied string index.
Negative offsets search backwards from the position of the character that many characters from the end of the string.

Here is an example of backwards stepping through instances of a string with this function:

<?php
function backwardStrpos($haystack, $needle, $offset = 0){
   
$length = strlen($haystack);
   
$offset = ($offset > 0)?($length - $offset):abs($offset);
   
$pos = strpos(strrev($haystack), strrev($needle), $offset);
    return (
$pos === false)?false:( $length - $pos - strlen($needle) );
}

$pos = 0;
$count = 0;
echo
"Test1<br/>";
while((
$pos = backwardStrpos("012340567890", "0", $pos)) !== false){
     echo
$pos."<br/>";
   
$pos--;
    if(
$pos < 0){
        echo
"Done<br/>";break;
    }
}
echo
"---===---<br/>\nTest2<br/>";
echo
backwardStrpos("12341234", "1", 2)."<br/>";
echo
backwardStrpos("12341234", "1", -2);
?>

Outputs:
Test1
11
5
0
Done
---===---
Test2
0
4

With Test2 the first line checks from the first 3 in "12341234" and runs backwards until it finds a 1 (at position 0)

The second line checks from the second 2 in "12341234" and seeks towards the beginning for the first 1 it finds (at position 4).

This function is useful for php4 and also useful if the offset parameter in the existing strrpos is equally confusing to you as it is for me.
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