RegEx (preg_match_all in PHP) to capture series of <tags containing numbers> up to the first alphanumeric character

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The problem here is the conflict between numbers and alphanumeric in the problem description.

Given the text:

＜0＞＜1＞＜2＞＜3＞＜4＞＜5＞＜6＞＜7＞＜8＞＜9＞＜10＞＜11＞＜12＞＜13＞＜14＞＜15＞＜16＞＜17＞＜18＞The next 11 keys can change the SWING from OFF (50%) to ＜19＞＜20＞＜21＞＜22＞＜23＞＜24＞＜25＞80＜26＞＜27＞＜28＞＜29＞＜30＞＜31＞＜32＞% during arpeggiator or sequencer operation.＜33＞＜34＞

I need to extract the following four groups:

＜0＞＜1＞＜2＞＜3＞＜4＞＜5＞＜6＞＜7＞＜8＞＜9＞＜10＞＜11＞＜12＞＜13＞＜14＞＜15＞＜16＞＜17＞＜18＞
＜19＞＜20＞＜21＞＜22＞＜23＞＜24＞＜25＞
＜26＞＜27＞＜28＞＜29＞＜30＞＜31＞＜32＞
＜33＞＜34＞

Reason: we want to display this in a much more user-friendly way as...

[1]The next 11 keys can change the SWING from OFF (50%) to [2]80[3]% during arpeggiator or sequencer operation.[4]

Current code:

$pattern = '＜[\d＜＞' . REGSTART . REGEND . REGSTARTSQ . REGENDSQ . '\{\}]+＞';
$numberofsupertags = preg_match_all('/(' . $pattern . ')/', $source, $superchunks);
echo '<pre>';
print_r($superchunks);
echo '</pre><br>';

(REGSTART/REGEND/REGSTARTSQ/REGENDSQ refer to other possible pairs of symbols, like 【】 or 〖〗 etc.)

gives three groups:

＜0＞＜1＞＜2＞＜3＞＜4＞＜5＞＜6＞＜7＞＜8＞＜9＞＜10＞＜11＞＜12＞＜13＞＜14＞＜15＞＜16＞＜17＞＜18＞
＜19＞＜20＞＜21＞＜22＞＜23＞＜24＞＜25＞80＜26＞＜27＞＜28＞＜29＞＜30＞＜31＞＜32＞
＜33＞＜34＞

As you can see, the RegEx fails to take into account sequences of only numbers between tags.

I've tried lots of things:

$pattern = '([＜|' . REGSTART . REGSTARTSQ . '|\{]\d+?[＞|' . REGEND . REGENDSQ . | \}])+';
$pattern = '＜[\d＜＞' . REGSTART . REGEND . REGSTARTSQ . REGENDSQ . '\{\}]+[＞(?=\d)|＞]';

...but to no avail.

What is the correct solution and where do I go wrong? This looks really simple, but apparently it isn't.

php regex
1 Answers

You can use

(?:＜(?:{\d+}|【\d+】|〖\d+〗|\d+)＞)+

See the regex demo. Details:

  • (?: - start of a non-capturing group:
    • ＜ - a ＜ char
    • (?:{\d+}|【\d+】|〖\d+〗|\d+) - one of the alternatives: { + one or more digits + }, 【 + one or more digits + 】, 〖 + one or more digits + 〗 or one or more digits
    • ＞ - a ＞ char
  • )+ - one or more times.

See the PHP demo:

$source = '＜0＞＜1＞＜2＞＜3＞＜4＞＜5＞＜6＞＜7＞＜8＞＜9＞＜10＞＜11＞＜12＞＜13＞＜14＞＜15＞＜16＞＜17＞＜18＞The next 11 keys can change the SWING from OFF (50%) to ＜19＞＜20＞＜21＞＜22＞＜23＞＜24＞＜25＞80＜26＞＜27＞＜28＞＜29＞＜30＞＜31＞＜32＞% during arpeggiator or sequencer operation.＜33＞＜34＞';

$cnt = 0;
echo preg_replace_callback('~(?:＜(?:{\d+}|【\d+】|〖\d+〗|\d+)＞)+~u', function($m) use (&$cnt) {
    return '['. ++$cnt .']';
}, $source);
// => [1]The next 11 keys can change the SWING from OFF (50%) to [2]80[3]% during arpeggiator or sequencer operation.[4]
user_38329700
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