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
Description
int mb_strpos
( string
$haystack
, string $needle
[, int $offset = 0
[, string $encoding
]] )Finds position of the first occurrence of a string in a string.
Performs a multi-byte safe strpos() operation based on number of characters. The first character's position is 0, the second character position is 1, and so on.
Parameters
-
haystack -
The string being checked.
-
needle -
The string to find in
haystack. In contrast with strpos(), numeric values are not applied as the ordinal value of a character. -
offset -
The search offset. If it is not specified, 0 is used.
-
encoding -
The
encodingparameter is the character encoding. If it is omitted, the internal character encoding value will be used.
Return Values
Returns the numeric position of
the first occurrence of needle in the
haystack string. If
needle is not found, it returns FALSE.
See Also
- mb_internal_encoding() - Set/Get internal character encoding
- strpos() - Find the position of the first occurrence of a substring in a string
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User Contributed Notes
mb_strpos - [5 notes]
brendel at krumedia dot de ¶
5 years ago
stestagg at talk21 dot com ¶
6 years ago
sorry, my previous post had an error. replace the 1000 with strlen($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 $length, thus this reduces the functionality of mb_substr compared to substr
stestagg at talk21 dot com ¶
6 years ago
a sample mb_str_replace function:
function mb_str_replace($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 ¶
6 years ago
It appears that the $offset value is a character count not a byte count. (This may seem obvious but it isn't explicitly stated)
zangaru at hotmail dot com ¶
5 years ago
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
}
==============================================