PHP 7.2.7 Released

preg_replace_callback_array

(PHP 7)

preg_replace_callback_array正規表現検索を行い、コールバック関数を使用して置換を行う

説明

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

この関数の動作は、preg_replace_callback() に似ていますが、 コールバック関数が、パターン単位ペースで実行されるところが異なります。

パラメータ

patterns_and_callbacks

パターンをキーとし、コールバック関数を値とする連想配列です。

subject

文字列あるいは文字列の配列で、 検索および置換の対象となる文字列を指定します。

limit

subject 文字列における 各パターンの最大置換回数。デフォルトは -1 (無制限) です。

count

指定した場合は、置換を行った回数がここに格納されます。

返り値

preg_replace_callback_array() は、 subject が配列の場合には配列を、 それ以外の場合は文字列を返します。 エラー時の返り値は NULL となります。

マッチするものが見つかった場合は新しい subject を返し、それ以外の場合はもとの subject をそのまま返します。

例1 preg_replace_callback_array() の例

<?php
$subject 
'Aaaaaa Bbb';

preg_replace_callback_array(
    [
        
'~[a]+~i' => function ($match) {
            echo 
strlen($match[0]), ' matches for "a" found'PHP_EOL;
        },
        
'~[b]+~i' => function ($match) {
            echo 
strlen($match[0]), ' matches for "b" found'PHP_EOL;
        }
    ],
    
$subject
);
?>

上の例の出力は以下となります。

6 matches for "a" found
3 matches for "b" found

参考

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User Contributed Notes 3 notes

up
9
drevilkuko at gmail dot com
2 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.
4 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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