strrchr

(PHP 4, PHP 5, PHP 7, PHP 8)

strrchr — Trova l'ultima occorrenza di un carattere in una stringa

Descrizione

strrchr(string $haystack, string $needle): string

Questa funzione restituisce la porzione di haystack che inizia dall'ultima occorrenza di needle e finisce al termine di haystack.

Restituisce false se needle non viene trovato.

Se needle contiene più di un carattere, in PHP 4 si utilizza solo il primo. Questo comportamento è differente rispetto a strchr().

Se needle non è una stringa, viene convertito in un intero e utilizzato come valore ordinale di un carattere.

Example #1 Esempio di uso di strrchr()

<?php
// L'ultima directory in $PATH
$dir = substr(strrchr($PATH, ":"), 1);

// ottiene qualsiasi cosa dopo l'ultimo newline
$text = "Line 1\nLine 2\nLine 3";
$last = substr(strrchr($text, 10), 1 );
?>

strrchr() è affidabile con i dati binari dal PHP 4.3.0

Vedere anche strstr(), substr() e stristr().

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User Contributed Notes 8 notes

down

matthewkastor at live dot com ¶

13 years ago

<?php

/**

 * Removes the preceeding or proceeding portion of a string

 * relative to the last occurrence of the specified character.

 * The character selected may be retained or discarded.

 * 

 * Example usage:

 * <code>

 * $example = 'http://example.com/path/file.php';

 * $cwd_relative[] = cut_string_using_last('/', $example, 'left', true);

 * $cwd_relative[] = cut_string_using_last('/', $example, 'left', false);

 * $cwd_relative[] = cut_string_using_last('/', $example, 'right', true);

 * $cwd_relative[] = cut_string_using_last('/', $example, 'right', false);

 * foreach($cwd_relative as $string) {

 *     echo "$string <br>".PHP_EOL;

 * }

 * </code>

 * 

 * Outputs:

 * <code>

 * http://example.com/path/

 * http://example.com/path

 * /file.php

 * file.php

 * </code>

 * 

 * @param string $character the character to search for.

 * @param string $string the string to search through.

 * @param string $side determines whether text to the left or the right of the character is returned.

 * Options are: left, or right.

 * @param bool $keep_character determines whether or not to keep the character.

 * Options are: true, or false.

 * @return string

 */

function cut_string_using_last($character, $string, $side, $keep_character=true) {

    $offset = ($keep_character ? 1 : 0);

    $whole_length = strlen($string);

    $right_length = (strlen(strrchr($string, $character)) - 1);

    $left_length = ($whole_length - $right_length - 1);

    switch($side) {

        case 'left':

            $piece = substr($string, 0, ($left_length + $offset));

            break;

        case 'right':

            $start = (0 - ($right_length + $offset));

            $piece = substr($string, $start);

            break;

        default:

            $piece = false;

            break;

    }

    return($piece);

}

?>

down

sekati at gmail dot com ¶

18 years ago

just a small addition to carlos dot lage at gmail dot com note which makes it a bit more useful and flexible:

<?php
// return everything up to last instance of needle
// use $trail to include needle chars including and past last needle 
function reverse_strrchr($haystack, $needle, $trail) {
    return strrpos($haystack, $needle) ? substr($haystack, 0, strrpos($haystack, $needle) + $trail) : false;
}
// usage:
$ns = (reverse_strrchr($_SERVER["SCRIPT_URI"], "/", 0));
$ns2 = (reverse_strrchr($_SERVER["SCRIPT_URI"], "/", 1));
echo($ns . "<br>" . $ns2);
?>

down

dchris1 at bigpond dot net dot au ¶

20 years ago

The function provided by marcokonopacki at hotmail dot com isn't really a reverse-version of strrchr(), rather a reverse version of strchr(). It returns everything from the start of $haystack up to the FIRST instance of the $needle. This is basically a reverse of the behavior which you expect from strchr(). A reverse version of strrchr() would return everything in $haystack up to the LAST instance of $needle, eg:

<?php
// reverse strrchr() - PHP v4.0b3 and above
function reverse_strrchr($haystack, $needle)
{
    $pos = strrpos($haystack, $needle);
    if($pos === false) {
        return $haystack;
    }
    return substr($haystack, 0, $pos + 1);
}
?>

Note that this function will need to be modified slightly to work with pre 4.0b3 versions of PHP due to the return type of strrpos() ('0' is not necessarily 'false'). Check the documentation on strrpos() for more info. 

A function like this can be useful for extracting the path to a script, for example:

<?
$string = "/path/to/the/file/filename.php";

echo reverse_strrchr($string, '/'); // will echo "/path/to/the/file/"
?>

down

readless at gmx dot net ¶

18 years ago

to: repley at freemail dot it

the code works very well, but as i was trying to cut script names (e.g.: $_SERVER["SCRIPT_NAME"] => /index.php, cut the string at "/" and return "index.php") it returned nothing (false). i've modified your code and now it works also if the needle is the first char.
- regards from germany

<?php
//strxchr(string haystack, string needle [, bool int leftinclusive [, bool int rightinclusive ]])
function strxchr($haystack, $needle, $l_inclusive = 0, $r_inclusive = 0){
   if(strrpos($haystack, $needle)){
       //Everything before last $needle in $haystack.
       $left =  substr($haystack, 0, strrpos($haystack, $needle) + $l_inclusive);
 
       //Switch value of $r_inclusive from 0 to 1 and viceversa.
       $r_inclusive = ($r_inclusive == 0) ? 1 : 0;
 
       //Everything after last $needle in $haystack.
       $right =  substr(strrchr($haystack, $needle), $r_inclusive);
 
       //Return $left and $right into an array.
       return array($left, $right);
   } else {
       if(strrchr($haystack, $needle)) return array('', substr(strrchr($haystack, $needle), $r_inclusive));
       else return false;
   }
}
?>

down

freakinunreal at hotmail dot com ¶

18 years ago

to marcokonopacki at hotmail dot com.

I had to make a slight change in your function for it to return the complete needle inclusive.

// Reverse search of strrchr.
function strrrchr($haystack,$needle)
{

   // Returns everything before $needle (inclusive).
   //return substr($haystack,0,strpos($haystack,$needle)+1);
   // becomes
   return substr($haystack,0,strpos($haystack,$needle)+strlen($needle));
}

Note: the +1 becomes +strlen($needle)

Otherwise it only returns the first character in needle backwards.

down

Primo Anderson Do S?tio ¶

19 years ago

$filename = 'strrchr_test.php';
print strrchr( $filename, '.' );

Result:
.php

$other_filename = 'strrchr_test.asp.php';
print  strrchr( $other_filename, '.' );

Result:
.php

down

marcokonopacki at hotmail dot com ¶

21 years ago

<?

// Reverse search of strrchr.
function strrrchr($haystack,$needle)
{

    // Returns everything before $needle (inclusive).
    return substr($haystack,0,strpos($haystack,$needle)+1);
    
}

$string = "FIELD NUMBER(9) NOT NULL";

echo strrrchr($string,")"); // Will print FIELD (9)

?>

down

-5

carlos dot lage at gmail dot com ¶

19 years ago

I used dchris1 at bigpond dot net dot au 's reverse strrchr and reduced it to one line of code and fixed it's functionality - the real strrchr() returns FALSE if the needle is not found, not the haystack :)

<?php
// reverse strrchr()
function reverse_strrchr($haystack, $needle)
{
                return strrpos($haystack, $needle) ? substr($haystack, 0, strrpos($haystack, $needle) +1 ) : false;
} 
?>

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