SunshinePHP 2019

preg_replace_callback_array

(PHP 7)

preg_replace_callback_arrayRealizar una búsqueda y sustitución de expresión regular con retrollamadas

Descripción

mixed preg_replace_callback_array ( array $patterns_and_callbacks , mixed $subject [, int $limit = -1 [, int &$count ]] )

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

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User Contributed Notes 3 notes

up
9
drevilkuko at gmail dot com
3 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
       
);
?>
up
3
Sz.
10 months ago
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.)
up
-2
jfcherng at NOSPAM dot gmail dot com
2 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;
}

// }

?>
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