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run code in 300+ PHP versions simultaneously
<?php function tagify($str, $baseUrl = '/board/') { $baseUrl = rtrim($baseUrl, '/'); return preg_replace('/ (?!<a[^<>]*>[^\#]*) # Dont match if there is an opening link tag and any chars after it. \#([-_\w]+\b) # Match the hashtag. (?![^<]*<\/a>) # Ignore any closing link tag including any chars before it not in hashtag. /ix', '<a href="'.$baseUrl.'/$1">#$1</a>', $str); } $str = <<<STR This is <a href="http://foo.com">This is #foo</a>. Simple #html-stuff text <a href="http://foobar.com#baz">#simple</a> <span class="simple">simple #simple text text</span> STR; echo tagify($str);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
This is <a href="http://foo.com">This is #foo</a>. Simple <a href="/board/html-stuff">#html-stuff</a> text <a href="http://foobar.com#baz">#simple</a> <span class="simple">simple <a href="/board/simple">#simple</a> text text</span>

preferences:
299.62 ms | 406 KiB | 460 Q