strrchr

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

strrchr — 文字列中に文字が最後に現れる場所を取得する

説明

strrchr(string $haystack, string $needle, bool $before_needle = false): string|false

この関数は、文字列 haystack の中で needle が最後に現れた位置から、 haystack の終わりまでを返します。

パラメータ

haystack

検索対象の文字列。

needle

needle がひとつ以上の文字を含んでいる場合は、最初のもののみが使われます。この動作は、 strstr() とは異なります。

PHP 8.0.0 より前のバージョンでは、needle が文字列でない場合、数値に変換され、文字の通常の値として扱われていました。この振る舞いは PHP 7.3.0 以降では推奨されないので、この機能を使用しないことを強く推奨します。意図した動作に依存する場合、 needle を string に明示的にキャストするか、明示的に chr() 関数を呼び出すべきでしょう。

before_needle

true にすると、 haystack の中で最後に needle が現れる箇所より前の部分を返します (needle は含めません)。

戻り値

この関数は、部分文字列を返します。 needle が見つからない場合は false を返します。

変更履歴

バージョン	説明
8.3.0	`before_needle` が追加されました。
8.0.0	`needle` は、空文字列を受け入れるようになりました。
8.0.0	`needle` に数値を渡すことはサポートされなくなりました。
7.3.0	`needle` に数値を渡すことは非推奨になりました。

例

例1 strrchr() の例

<?php
$ext = strrchr('somefile.txt', '.');
echo "file extension: $ext \n";
$ext = $ext ? strtolower(substr($ext, 1)) : '';
echo "file extension: $ext";
?>

上の例の出力は、たとえば以下のようになります。

file extension: .txt
file extension: txt

注意

注意: この関数はバイナリデータに対応しています。

参考

strstr() - 文字列が最初に現れる位置を見つける
strrpos() - 文字列中に、ある部分文字列が最後に現れる場所を探す

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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 ¶

19 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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