mb_strpos

(PHP 4 >= 4.0.6, PHP 5)

mb_strpos — 文字列の中に指定した文字列が最初に現れる位置を見つける

説明

int mb_strpos ( string $haystack , string $needle [, int $offset [, string $encoding ]] )

ある文字列の中で別の文字列が最初に現れる位置を見つけます。

マルチバイト文字列に正しくマッチするように strpos() を拡張したもので、最初の 1 文字目の位置が 0 、2 文字目の文字が 1 というようになります。

パラメータ

haystack: 調べたい文字列。
needle: haystack の中での位置を調べる文字列。
offset: 検索オフセット。指定されない場合は、0 が使用されます。
encoding: encoding パラメータには文字エンコーディングを指定します。省略した場合は、内部文字エンコーディングを使用します。

返り値

文字列 haystack の中で needle が最初に現れる位置を数字で返します。 needle が見付からなかった場合、FALSE を返します。

参考

mb_strrchr

mb_strlen

Last updated: Fri, 29 Aug 2008

add a note User Contributed Notes
mb_strpos

brendel at krumedia dot de
11-Mar-2008 05:42


mb_strpos() used in a loop on a long string may become very slow even if you provide the $offset. Unlike strpos(), mb_strpos() has to skip the number of characters

 every call specified by $offset to get the real byte position used internally. (Whereas strpos can just add the offset.)



If your encoding is UTF-8 and you try to find only single characters with ordinal <= 127 you may still use strpos(), substr(), ... This works cause every byte of a UTF-8 sequence is >= 128.



Greetz maz

zangaru at hotmail dot com
05-Jul-2007 10:42


Hello,



Just replaced strpos() with mb_strpos() and now I am getting following error:



PHP Warning:  mb_strpos() [<a href='function.mb-strpos'>function.mb-strpos</a>]: Empty delimiter



PHP version: 5.2.3

OS: Win XP Prof

Web Server: IIS



I checked your bugs and mentioned that mb_string functions have been fixed as of 5.2.0 but it does not seem to be the case (Bug #39400).



My code:

==============================================



$charOut = mb_substr($tmpStr, $tmpKey[0], 1); 

$posOut = mb_strpos($charList, $charOut); 

if ($posOut !== FALSE) {

    // do something here

}



==============================================

stestagg at talk21 dot com
05-Aug-2006 05:12


sorry, my previous post had an error.  replace the 1000 with strlen($haystack) to handle strings longer than 1000 chars.



btw. This is an issue with the mbstring functions.  you can't specify the $encoding without specifying a $length, thus this reduces the functionality of mb_substr compared to substr

stestagg at talk21 dot com
04-Aug-2006 09:42


a sample mb_str_replace function:



function mb_str_replace($haystack, $search,$replace, $offset=0,$encoding='auto'){

    $len_sch=mb_strlen($search,$encoding);

    $len_rep=mb_strlen($replace,$encoding);

    

    while (($offset=mb_strpos($haystack,$search,$offset,$encoding))!==false){

        $haystack=mb_substr($haystack,0,$offset,$encoding)

            .$replace

            .mb_substr($haystack,$offset+$len_sch,1000,$encoding);

        $offset=$offset+$len_rep;

        if ($offset>mb_strlen($haystack,$encoding))break;

    }

    return $haystack;

}

stestagg at talk21 dot com
04-Aug-2006 09:39


It appears that the $offset value is a character count not a byte count.  (This may seem obvious but it isn't explicitly stated)

add a note

mb_strrchr

mb_strlen

Last updated: Fri, 29 Aug 2008