PHP Australia Conference 2015

strripos

(PHP 5)

strriposFind position of last occurrence of a case-insensitive string in a string

Description

int strripos ( string $haystack , string $needle [, int $offset = 0 ] )

Find position of last occurrence of a case-insensitive string in a string. Unlike strrpos(), strripos() is case-insensitive.

Parameters

haystack

The string to search in

needle

Note that the needle may be a string of one or more characters.

offset

The offset parameter may be specified to begin searching an arbitrary number of characters into the string.

Negative offset values will start the search at offset characters from the start of the string.

Return Values

Returns the numerical position of the last occurrence of needle. Also note that string positions start at 0, and not 1.

If needle is not found, FALSE is returned.

Warning

This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE, such as 0 or "". Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

Examples

Example #1 A simple strripos() example

<?php
$haystack 
'ababcd';
$needle   'aB';

$pos      strripos($haystack$needle);

if (
$pos === false) {
    echo 
"Sorry, we did not find ($needle) in ($haystack)";
} else {
    echo 
"Congratulations!\n";
    echo 
"We found the last ($needle) in ($haystack) at position ($pos)";
}
?>

The above example will output:

   Congratulations!
   We found the last (aB) in (ababcd) at position (2)

See Also

  • strpos() - Find position of first occurrence of a string
  • stripos() - Find position of first occurrence of a case-insensitive string
  • strrchr() - Find the last occurrence of a character in a string
  • substr() - Return part of a string
  • stristr() - Case-insensitive strstr
  • strstr() - Find first occurrence of a string

add a note add a note

User Contributed Notes 7 notes

up
5
Yanik Lupien
7 years ago
Simple way to implement this function in PHP 4

<?php
if (function_exists('strripos') == false) {
    function
strripos($haystack, $needle) {
        return
strlen($haystack) - strpos(strrev($haystack), $needle);
    }
}

?>
up
1
peev[dot]alexander at gmail dot com
6 years ago
OK, I guess this will be the final function implementation for PHP 4.x versions ( my previous posts are invalid )

<?php

if(!function_exists("stripos")){
    function
stripos$str, $needle, $offset = ){
        return
strposstrtolower( $str ), strtolower( $needle ), $offset  );
    }
/* endfunction stripos */
}/* endfunction exists stripos */

if(!function_exists("strripos")){
    function
strripos$haystack, $needle, $offset = ) {
        if(  !
is_string( $needle )  )$needle = chrintval( $needle )  );
        if( 
$offset < ){
           
$temp_cut = strrevsubstr( $haystack, 0, abs($offset) )  );
        }
        else{
           
$temp_cut = strrev(    substr(   $haystack, 0, max(  ( strlen($haystack) - $offset ), )   )    );
        }
        if(   ( 
$found = stripos( $temp_cut, strrev($needle) )  ) === FALSE   )return FALSE;
       
$pos = (   strlen$haystack  ) - (  $found + $offset + strlen( $needle )  )   );
        return
$pos;
    }
/* endfunction strripos */
}/* endfunction exists strripos */
?>
up
2
Anonymous
4 years ago
Generally speaking, linear searches are from start to end, not end to start - which makes sense from a human perspective. If you need to find strings in a string backwards, reverse your haystack and needle rather than manually chopping it up.
up
0
admin at e-xxi dot net
4 years ago
strripos() has very strange behaviour when you provide search position. For some reason it searches forward from the given position, instead of searching backward, that is more logical.

For example if you want to find instanse of $what, previous to the last, strripos($where, $what, $last_what_pos-1) will not wark as expected. It will return $last_what_pos again and again. And that has no sence at all.

To prevent this, I just used $prev_last_what_pos = strripos(substr($where,0,$last_what_pos), $what);
up
0
peev[dot]alexander at gmail dot com
6 years ago
I think you shouldn't underestimate the length of $needle in the search of THE FIRST POSITION of it's last occurrence in the string. I improved the posted function, with added support for offset. I think this is an exact copy of the real function:

<?php
if(!function_exists("strripos")){
    function
strripos($haystack, $needle, $offset=0) {
        if(
$offset<0){
           
$temp_cut = strrevsubstr( $haystack, 0, abs($offset) )  );
        }
        else{
           
$temp_cut = strrevsubstr( $haystack, $offset )  );
        }
       
$pos = strlen($haystack) - (strpos($temp_cut, strrev($needle)) + $offset + strlen($needle));
        if (
$pos == strlen($haystack)) { $pos = 0; }
        return
$pos;
    }
/* endfunction strripos*/
}/* endfunction exists strripos*/
?>
up
0
ElectroFox
7 years ago
Sorry, I made that last post a bit prematurely.  One more thing wrong with the simple php4 version is that it breaks if the string is not found.  It should actually look like this:

<?php
if (function_exists('strripos') == false) {
    function
strripos($haystack, $needle) {
       
$pos = strlen($haystack) - strpos(strrev($haystack), strrev($needle));
        if (
$pos == strlen($haystack)) { $pos = 0; }
        return
$pos;
    }
}
?>

Note, we now check to see if the $needle was found, and if it isn't, we return 0.
up
-1
dimmav at in dot gr
6 years ago
Suppose you just need a stripos function working backwards expecting that strripos does this job, you better use the following code of a custom function named strbipos:

<?php
function strbipos($haystack="", $needle="", $offset=0) {
// Search backwards in $haystack for $needle starting from $offset and return the position found or false

   
$len = strlen($haystack);
   
$pos = stripos(strrev($haystack), strrev($needle), $len - $offset - 1);
    return ( (
$pos === false) ? false : $len - strlen($needle) - $pos );
}

// Test
$body = "01234Xy7890XYz456xy90";
$str = "xY";
$len = strlen($body);
echo
"TEST POSITIVE offset VALUES IN strbipos<br>";
for (
$i = 0; $i < $len; $i++) {
    echo
"Search in [$body] for [$str] starting from offset [$i]: [" . strbipos($body, $str, $i) . "]<br>";
}
?>

Note that this function does exactly what it says and its results are different comparing to PHP 5 strripos function.
To Top