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)
mb_ereg_search_setpos — Set start point of next regular expression match
Descrierea
mb_ereg_search_setpos
( int
$offset
) : boolmb_ereg_search_setpos() sets the starting point of a match for mb_ereg_search().
Parametri
-
offset -
The position to set. If it is negative, it counts from the end of the string.
Valorile întoarse
Întoarce valoarea true în cazul
succesului sau false în cazul eșecului.
Istoricul schimbărilor
| Versiune | Descriere |
|---|---|
| 7.1.0 |
Support for negative offsets has been added.
|
Note
Notă:
Codificarea internă a caracterelor sau codificarea caracterelor specificată de funcția mb_regex_encoding() va fi utilizată în calitate de codificare a caracterelor pentru această funcție.
A se vedea și
- 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
