For those who read manual not in English and figure out that example code returns not the same result as in documentation
You need put in example patter modifier "u" to get same result:
<?php
$subject = array('1', 'а', '2', 'б', '3', 'А', 'Б', '4');
// Added "u"
$pattern = array('/\d/u', '/[а-я]/u', '/[1а]/u');
$replace = array('А:$0', 'Б:$0', 'В:$0');
?>
preg_filter
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
preg_filter — Perform a regular expression search and replace
Descrizione
preg_filter(
string|array
string|array
string|array
int
int
): string|array|null
string|array
$pattern,string|array
$replacement,string|array
$subject,int
$limit = -1,int
&$count = null): string|array|null
preg_filter() is identical to preg_replace() except it only returns the (possibly transformed) subjects where there was a match. For details about how this function works, read the preg_replace() documentation.
Elenco dei parametri
Parameters are described in the documentation for preg_replace().
Valori restituiti
Returns an array if the subject
parameter is an array, or a string otherwise.
If no matches are found or an error occurred, an empty array
is returned when subject is an array
or null otherwise.
Errori/Eccezioni
If the regex pattern passed does not compile to a valid regex, an E_WARNING is emitted.
Esempi
Example #1 Example comparing preg_filter() with preg_replace()
<?php
$subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4');
$pattern = array('/\d/', '/[a-z]/', '/[1a]/');
$replace = array('A:$0', 'B:$0', 'C:$0');
echo "preg_filter returns\n";
print_r(preg_filter($pattern, $replace, $subject));
echo "preg_replace returns\n";
print_r(preg_replace($pattern, $replace, $subject));
?>Il precedente esempio visualizzerà:
preg_filter returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[7] => A:4
)
preg_replace returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[5] => A
[6] => B
[7] => A:4
)
Vedere anche:
- PCRE Patterns
- preg_quote() - Inserisce il carattere di escape nei caratteri delle espressioni regolari
- preg_replace() - Esegue una ricerca ed una sostituzione con le espressioni regolari
- preg_replace_callback() - Esegue ricerche e sostituzioni con espressioni regolari usando una callback
- preg_grep() - Restituisce una matrice degli elementi riconosciuti tramite le espressioni regolari
- preg_last_error() - Returns the error code of the last PCRE regex execution
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User Contributed Notes 6 notes
forsoap at gmail dot com ¶
8 years ago
bienvenunet at yahoo dot com ¶
7 years ago
If you don't want to actually replace the matches, just filter the array to them, make the replacement parameter '$0'.
<?php
$subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4');
$result = preg_filter('/\d/', '$0', $subject); // ['1','2','3','4']
?>
sajina_99 at hotmail dot de ¶
13 years ago
As I had to work with PHP5.2.X and needed preg_filter I wrote a quick and dirty workaround.
<?php
if (!function_exists('preg_filter')) {
function preg_filter($pattern, $replace, $subject, $limit = -1 , &$count = null) {
if(!is_array($subject)) {
$noArray = 1 ;
$subject = array($subject);
}
$preg = preg_replace($pattern, $replace, $subject, $limit, &$count);
$diff = array_diff($preg, $subject);
if($noArray == 1) $diff = implode($diff) ;
return $diff ;
}
}
?>
MrBertie ¶
13 years ago
Another way to filter an array, and simply return the matching items: preg_grep!
fgmhhfg at gmail dot com ¶
10 years ago
As for the php 5.5.3 version, the example turn out like:
Array
(
[0] => A:1
[1] => B:a
...
)
