Based on some tests, I found these important traits of the function. (These would
be nice to see documented as part of its spec, e.g. for confirmation. Without that,
this is just experimental curiosity. Still better than guesswork, though! ;) )
1. Changes cascade over a subject across callbacks, i.e. a change made to a
subject by a callback will be seen by the next callback, if its pattern matches
the changed subject.
(But a change made by a previous call of the *same* callback (on any subject)
will not be seen by that callback again.)
2. The pattern + callback pairs will be applied in the order of their appearance
in $patterns_and_callbacks.
3. The callback can't be null (or '') for a quick shortcut for empty replacements.
4. Overall, the algorithm starts iterating over $patterns_and_callbacks, and then
feeds each $subject to the current callback, repeatedly for every single match
of its pattern on the current subject (unlike "preg_match_all", that is, which
can do the same in one go, returning the accumulated results in an array).
This basically means that the "crown jewel", an even more efficient function:
"preg_replace_all_callback_array" is still missing from the collection.
(Of course, that would better fit a new design of the regex API, where one
API could flexibly handle various different modes via some $flags = [] array.)
5. (This last one is not specific to this function, but inherent to regexes, OTOH,
it's probably more relevant here than anywhere else in PHP's regex support.)
Even apparently simple cases can generate a crazy (and difficult-to-predict)
number of matches, and therefore callback invokations, so remember the set
$limit, where affordable. But, of course, try to sharpen your patterns first!
E.g. use ^...$ anchoring to avoid unintended extra calls on matching substrings
of a subject, (I.e. '/.*/', without anchoring, would match twice: once for the
whole subject, and then for a trailing empty substring -- but I'm not quite sure
this should actually be correct behavior, though.)
preg_replace_callback_array
(PHP 7, PHP 8)
preg_replace_callback_array — Realizar una búsqueda y sustitución de expresión regular con retrollamadas
Descripción
preg_replace_callback_array(
array
mixed
int
int
): mixed
array
$patterns_and_callbacks,mixed
$subject,int
$limit = -1,int
&$count = ?): mixed
El comportamiento de esta función es similar a la de preg_replace_callback(), excepto que las retrollamadas se ejecutan en función de cada patrón.
Parámetros
-
patterns_and_callbacks -
Un array asociativo con correspondencias entre patrones (claves) y retrollamadas (valores).
-
subject -
El sujeto. Un string o array con varios strings para la búsqueda y sustitución.
-
limit -
Las sustituciones máximas posibles para cada patrón en cada string de
subject. Su valor predeterminado es de-1(sin límite). -
count -
La cuenta. Si se especifica, esta variable contrendrá el número de sustituciones hechas.
Valores devueltos
preg_replace_callback_array() devuelve un array si el
parámetro subject es un array, o un string
en caso contrario. En caso de error devuelve null
Si se encuentran coincidencias, será devuelto el nuevo sujeto; si no,
subject será devuelto sin cambios.
Ejemplos
Ejemplo #1 Ejemplo de preg_replace_callback_array()
<?php
$subject = 'Aaaaaa Bbb';
preg_replace_callback_array(
[
'~[a]+~i' => function ($match) {
echo strlen($match[0]), ' coincidencias de "a" encontradas', PHP_EOL;
},
'~[b]+~i' => function ($match) {
echo strlen($match[0]), ' coincidencias de "b" encontradas', PHP_EOL;
}
],
$subject
);
?>El resultado del ejemplo sería:
6 coincidencias de "a" encontradas 3 coincidencias de "b" encontradas
Ver también
- Patrones de PCRE
- preg_replace_callback() - Realiza una búsqueda y sustitución de una expresión regular usando una llamada de retorno
- preg_quote() - Escapar caracteres en una expresión regular
- preg_replace() - Realiza una búsqueda y sustitución de una expresión regular
- preg_last_error() - Devuelve el código de error de la última ejecución de expresión regular de PCRE
- Funciones anónimas
add a note
User Contributed Notes 3 notes
Sz. ¶
6 years ago
drevilkuko at gmail dot com ¶
9 years ago
finally!!!
before (<=php5.6):
<?php
$htmlString = preg_replace_callback(
'/(href="?)(\S+)("?)/i',
function (&$matches) {
return $matches[1] . urldecode($matches[2]) . $matches[3];
},
$htmlString
);
$htmlString = preg_replace_callback(
'/(href="?\S+)(%24)(\S+)?"?/i', // %24 = $
function (&$matches) {
return urldecode($matches[1] . '$' . $matches[3]);
},
$htmlString
);
?>
php7
<?php
$htmlString = preg_replace_callback_array(
[
'/(href="?)(\S+)("?)/i' => function (&$matches) {
return $matches[1] . urldecode($matches[2]) . $matches[3];
},
'/(href="?\S+)(%24)(\S+)?"?/i' => function (&$matches) {
return urldecode($matches[1] . '$' . $matches[3]);
}
],
$htmlString
);
?>
jfcherng at NOSPAM dot gmail dot com ¶
8 years ago
Here's a possible alternative in older PHP.
<?php
// if (!function_exists('preg_replace_callback_array')) {
function preg_replace_callback_array (array $patterns_and_callbacks, $subject, $limit=-1, &$count=NULL) {
$count = 0;
foreach ($patterns_and_callbacks as $pattern => &$callback) {
$subject = preg_replace_callback($pattern, $callback, $subject, $limit, $partial_count);
$count += $partial_count;
}
return preg_last_error() == PREG_NO_ERROR ? $subject : NULL;
}
// }
?>
