字符串函数
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strrchr

(PHP 4, PHP 5)

strrchr — 查找指定字符在字符串中的最后一次出现

说明

string strrchr ( string $haystack , mixed $needle )

该函数返回 haystack 字符串中的一部分，这部分以 needle 的最后出现位置开始，直到 haystack 末尾。

参数

haystack

在该字符串中查找。

needle

如果 needle 包含了不止一个字符，那么仅使用第一个字符。该行为不同于 strstr()。

如果 needle 不是一个字符串，那么将被转化为整型并被视为字符顺序值。

返回值

该函数返回字符串的一部分。如果 needle 未被找到，返回 FALSE。

更新日志

版本 说明
4.3.0 该函数是二进制安全的。

范例

Example #1 strrchr() 范例

<?php
// 获取 $PATH 中不含磁盘符号的目录
$dir = substr(strrchr($PATH, ":"), 1);

// 获取最后一行内容
$text = "Line 1\nLine 2\nLine 3";
$last = substr(strrchr($text, 10), 1 );
?>

注释

Note: 此函数可安全用于二进制对象。

参见

字符串函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 查找指定字符在字符串中的最后一次出现

用户评论:

matthewkastor at live dot com (30-Mar-2011 09:07)

<?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);
}
?>

corey [works at] effim [dot coooom] (28-Sep-2009 06:03)

Easiest way to get the domain off of an email:

<?php

$domain = strrchr($email, '@');

// gets @gmail.com, with the preceding @.

?>

It's not perfect (see above in the manual), but it's pretty damn good.

franzemmanuel at gmail dot com (24-May-2009 01:30)

this functions returns the full path of the current directory.
 
<?php

function CurrentFullPath()
{
    $root = $_SERVER['DOCUMENT_ROOT'] ;
    $self = $_SERVER['PHP_SELF'] ;
    return $root.mb_substr($self,0,-mb_strlen(strrchr($self,"/"))) ;
}

echo CurrentFullPath() ;

/*

If path is $path = "/home/me/www/pictures/control.php" ;

It will return :

/home/me/www/pictures

*/

?>

pnoexz at gmail dot com (06-Nov-2008 03:07)

Here is my function that returns the type of a file. I fint it easier to add other types of files, and simplier than the rest i have seen around.

<?php
function findExt($filename){
    $exts = array(
        '.jpg' => 'image',
        '.png' => 'image',
        '.php' => 'php',
        '.html' => 'html',
        '.swf' => 'flash',
        '.gz' => 'compressed',
        '.tar' => 'compressed',
    );
    $ext = strrchr($filename,'.');
    if ($exts[$ext]) { return $exts[$ext]; }
    else { return "unknown"; }
}
?>

equand at gmail dot com (29-May-2008 03:29)

a KiSS variant of a previous note

<?php
function fcheck($f = "test.doc")
{
 $fd = array(".xls" => "Microsoft Excel Worksheet",".doc" => "Microsoft Word Document",".pdf" => "Adobe Reader PDF File");
 $s = $fd[strrchr($f,'.')];
 if (!empty($s))
 {
  return $s;
 }
 else
 {
  return "Unknown file type";
 }
}

?>

Emmanuel Quiban (21-May-2008 03:32)

strrchr is useful also in determining file extensions.

Here is a sample code that determines the file type based on its file extension. This is useful in displaying the files in your page, without using the database for the file description list.

<?php
 /* File Extension Display using arrays
     by: Emmanuel Quiban (Philippines)
     BSCS 2002, AdU
     21-May-2008
 */

 // Sample file
 $filesample = "Mydocu.doc";

 //Array for file description. You can expand the array list further with other file types you want
 $filedes = array(
                "Microsoft Excel Worksheet",
                "Microsoft Word Document",
                "Adobe Reader PDF File");

 //Array for file extensions. Please take note that positions between the two arrays should be in sync with each other for correct file description.
 $fileext = array(".xls", ".doc", ".pdf");

 //This gets the file extension
 $ext = strrchr($filesample,'.');

 //This conditional statement checks if the file extension given is in the array and matches it with the file description
 if (in_array($ext,$fileext)) {

        //Search the array
        $ext2 = array_search($ext, $fileext);

        //Since the result of the array_search is in integer, you can now assign it as an array value
        $filetype = $filedes[$ext2];

        //Show the result
        echo $filetype;
 } else {
        $filetype = "Unknown file type";
 }
?>
-----
The output of the script above is:
Microsoft Word Document

Let's say even if the filename looks like "My.Docu.doc", strrchr still gets the value ".doc" because it gets the last occurance of the dot.
-----

You can also make it as a function, like this:

<?php
 /* File Extension Display using arrays
     by: Emmanuel Quiban (Philippines)
     BSCS 2002, AdU
     21-May-2008
 */
 function getFileType($yourfile){

 $filedes = array(
                "CompuServe GIF Image",
                "JPEG Image",
                "Portable Network Graphics (PNG) Image"
                );

 $fileext = array(".gif",".jpg",".png");

 $ext = strrchr($yourfile,'.');
 if (in_array($ext,$fileext)) {
        $ext2 = array_search($ext, $fileext);
        $filetype = $filedes[$ext2];
 } else {
        $filetype = "Unknown file type";
 }

 return $filetype;
 }
?>

subbz2k at yahoo dot de (02-Aug-2007 12:32)

i just recently did a function, that uses strrchr to format - let's say a currency - with 2 decimals. can also be done using number_format but you may NOT always want an automatic rounding of your decimals. thats there this function comes in handy:

<?php
function formatTwoDecimals($value, $trim)
{
   $after_comma = substr(strrchr($value, $trim), 0, 3);
   $in_front_of_comma = (int) $value;
   $final = $in_front_of_comma . $after_comma;

   return $final;
}

echo formatTwoDecimals("365.6078985", ".");
?>

this will produce
365.60

instead of
365.61
which will show up then you use number_format.

repley at freemail dot it (11-Aug-2006 02:57)

Final get file name and extension into an array with or without dot, using strrchr and strrchr_reverse.
Note our use of !==. Now work if the position of $needle in $haystack was the 0th (first) character like ".htaccess"
<?
//strxchr(string haystack, string needle [, bool int leftinclusive [, bool int rightinclusive ]])
function strxchr($haystack, $needle, $l_inclusive = 0, $r_inclusive = 0){
   //Note our use of !==. Now work if the position of $needle in $haystack was the 0th (first) character.
   if(strrpos($haystack, $needle) !== false){
       //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.
       $a = array($left, $right);
       return $a;
   }else{
       return false;
   }
}
?>

Repley

readless at gmx dot net (07-Jun-2006 03:55)

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;
   }
}
?>

repley at freemail dot it (18-May-2006 11:09)

Get file name and extension into an array with or without dot, using strrchr and strrchr_reverse.

<?
//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.
       $a = array($left, $right);
       return $a;
   }else{
       return false;
   }
}

//start test
$haystack = "unknown.txt.log.......gif.....jpeg";
$needle = ".";
$l_inclusive = 1; //1 for inclusive mode, 0 for NOT inclusive mode
$r_inclusive = 1; //1 for inclusive mode, 0 for NOT inclusive mode

$a = strxchr($haystack, $needle, $l_inclusive, $r_inclusive);
if($a){echo "Left: <strong>" . $a[0] . "</strong><br /> Right: <strong>" . $a[1] . "</strong>";}else{echo "Failed!";}
//end test
?>

Thanks to all.

Repley

sekati at gmail dot com (09-Apr-2006 01:43)

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);
?>

freakinunreal at hotmail dot com (25-Dec-2005 06:54)

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.

arcesis - gmail - com (11-Nov-2005 02:26)

A quick way to get file's extension (if it has one, otherwise you get an empty string), which can be used when you want to rename the file but keep the old extension. Or for similar purposes. Temporary variable is used just because it's slightly faster to store the value than to run the strrchr() function again.

<?php
$ext = substr(($t=strrchr("file.ext",'.'))!==false?$t:'',1);
?>

Primo Anderson Do Stio (29-Jul-2005 06:24)

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

Result:
.php

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

Result:
.php

carlos dot lage at gmail dot com (03-Apr-2005 07:45)

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;
}
?>

dchris1 at bigpond dot net dot au (17-Feb-2004 03:16)

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/"
?>

andfarm at thibs dot menloschool dot org (24-May-2003 12:24)

strrchr is also very useful for finding the extension of a file. For example:

$ext = strrchr($filename, ".");

and $ext will contain the extension of the file, including a ".", if the file has an extension, and FALSE if the file has no extension. If the file has multiple extensions, such as "evilfile.jpg.vbs", then this construction will just return the last extension.

marcokonopacki at hotmail dot com (14-Apr-2003 08:43)

<?

// 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)

?>

juancri at tagnet dot org (16-Nov-2002 11:02)

this functions returns the name of the current directory.
<?php
function currentd() {
    return substr(strrchr(`pwd`, '/'), 1);
}
?>