mb_strlen
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
mb_strpos
(PHP 4 >= 4.0.6, PHP 5)
mb_strpos — Find position of first occurrence of string in a string
说明
int mb_strpos
( string $haystack
, string $needle
[, int $offset
[, string $encoding
]] )
mb_strpos() returns the numeric position of the first occurrence of needle in the haystack string. If needle is not found, it returns FALSE.
mb_strpos() performs multi-byte safe strpos() operation based on number of characters. needle position is counted from the beginning of the haystack . First character's position is 0. Second character position is 1, and so on.
If encoding is omitted, internal character encoding is used.
offset is search offset. If it is not specified, 0 is used.
encoding is character encoding name. If it is omitted, internal character encoding is used.
See also mb_strrpos(), mb_internal_encoding(), strpos()
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User Contributed Notesmb_strpos
brendel at krumedia dot de
11-Mar-2008 08:42
11-Mar-2008 08:42
zangaru at hotmail dot com
06-Jul-2007 01:42
06-Jul-2007 01:42
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
06-Aug-2006 08:12
06-Aug-2006 08:12
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 $length, thus this reduces the functionality of mb_substr compared to substr
stestagg at talk21 dot com
05-Aug-2006 12:42
05-Aug-2006 12:42
a sample mb_str_replace function:
function mb_str_replace($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
05-Aug-2006 12:39
05-Aug-2006 12:39
It appears that the $offset value is a character count not a byte count. (This may seem obvious but it isn't explicitly stated)