Online PHP editor | refs for HNTle

<?php $input_lines = [ "abc-def/something/else/ [incl. slash if there is not character before it]", "abc-def-2019/something/else/", "abc-def-2019-2020/something/else/", "abc-def-125-2019/something/else/", "aaa-20199-2019/", "aaa", "aaa/", "aaa2019", "aaa2019test/", "aaa201aaa2019aaa2019/" ]; $pattern = '~^(?=[a-z\d-]*/)[a-zA-Z013-9-]+(?>2(?!0(?:19|20)(?!\d))|[a-zA-Z013-9-]+)*/?~'; foreach ($input_lines as $input_line) { echo preg_replace($pattern, '', $input_line) . PHP_EOL; }