3v4l.org

run code in 300+ PHP versions simultaneously
<?php $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> <span>foo #simple"onclick="alert('hi')" another STR; echo preg_replace('/(?!<a[^<>]*>[^#]+)#(\b[-_\w]+\b)(?![^<]*<\/a>)/', '<a href="/tags/$1">#$1</a>', $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 - 5.5.35, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.5 - 7.2.33, 7.3.12 - 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="/tags/html-stuff">#html-stuff</a> text <a href="http://foobar.com#baz">#simple</a> <span class="simple">simple <a href="/tags/simple">#simple</a> text text</span> <span>foo <a href="/tags/simple">#simple</a>"onclick="alert('hi')" another
preferences:
218.22 ms | 406 KiB | 345 Q