This method, like mb_ereg_search_pos, appears to use byte offsets, not character offsets. This seems counter intuitive for the mb_* methods, which inherently take a "character" view of strings, as opposed to a "byte" based view. Even the mb_strpos method returns a character offset.
The following code reveals this byte-oriented behaviour:
<?php
$x = 'abc456789'. "\u{1000}" .'abc4567890';
$re = 'ab.';
echo 'x='. $x .PHP_EOL;
echo 're='. $re .PHP_EOL;
mb_ereg_search_init( $x );
mb_internal_encoding( mb_detect_encoding( $x) );
echo 'mb_strlen='. mb_strlen( $x ) .PHP_EOL;
echo 'strlen='. strlen( $x ) .PHP_EOL;
foreach ( array( 0, 9, 10, 11, 12, 13 ) as $o ) {
mb_ereg_search_setpos( $o );
echo 'Offset='. $o
.' mb_substr='. mb_substr( $x, $o )
.' substr='. substr( $x, $o )
.' mb_ereg_search_regs='. print_r( mb_ereg_search_regs( $re ), true )
.PHP_EOL;
}
?>
With character offsets, we would expect offsets 11 and above to return no search result, whereas what we see is:
<?php
=abc456789ကabc4567890
re=ab.
mb_strlen=20
strlen=22
Offset=0 mb_substr=abc456789ကabc4567890 substr=abc456789ကabc4567890 mb_ereg_search_regs=Array
(
[0] => abc
)
Offset=9 mb_substr=ကabc4567890 substr=ကabc4567890 mb_ereg_search_regs=Array
(
[0] => abc
)
Offset=10 mb_substr=abc4567890 substr=��abc4567890 mb_ereg_search_regs=Array
(
[0] => abc
)
Offset=11 mb_substr=bc4567890 substr=�abc4567890 mb_ereg_search_regs=Array
(
[0] => abc
)
Offset=12 mb_substr=c4567890 substr=abc4567890 mb_ereg_search_regs=Array
(
[0] => abc
)
Offset=13 mb_substr=4567890 substr=bc4567890 mb_ereg_search_regs=
?>
mb_ereg_search_setpos
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
mb_ereg_search_setpos — Set start point of next regular expression match
Descrizione
mb_ereg_search_setpos() sets the starting point of a match for mb_ereg_search().
Elenco dei parametri
-
offset -
The position to set. If it is negative, it counts from the end of the string.
Valori restituiti
Restituisce true in caso di successo, false in caso di fallimento.
Log delle modifiche
| Versione | Descrizione |
|---|---|
| 7.1.0 |
Support for negative offsets has been added.
|
Note
Nota:
La codifica interna o la codifica dei caratteri specificata da mb_regex_encoding() sarà utilizzata come codifica ei caratteri per questa funzione.
Vedere anche:
- mb_regex_encoding() - Set/Get character encoding for multibyte regex
- mb_ereg_search_init() - Setup string and regular expression for a multibyte regular expression match
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User Contributed Notes 1 note
phpnet at osps dot net ¶
3 years ago
