Online PHP editor | refs for mIqga

<?php $meta_pattern = '/(?<=^|%3$s|\s)(?:(?!\S*%3$s\S*)\S+\s+){0,%2$d}(?:(?!\S*%3$s\S*%1$s)\S*)?%1$s\S*?(?:\s+\S+?){0,%2$d}(?=$|%3$s|\s)/'; $reg = sprintf($meta_pattern, preg_quote('search','/'), 3, preg_quote('$@','/')); $tests = array( array('input' => 'a b c d search e f g h', 'expected' => 'b c d search e f g'), array('input' => 'b c d search e f g h', 'expected' => ''), array('input' => 'a b c d search e f g', 'expected' => ''), array('input' => 'c d search e f g h', 'expected' => ''), array('input' => 'a b c d search e f', 'expected' => ''), array('input' => 'a$@b c d search e f g h', 'expected' => ''), array('input' => 'a b c d search e f g$@h', 'expected' => ''), array('input' => 'a b$@c d search e f g h', 'expected' => ''), array('input' => 'a b c d search e f$@g h', 'expected' => ''), array('input' => 'a b c$@d search e f g h', 'expected' => ''), array('input' => 'a b c d search e$@f g h', 'expected' => ''), array('input' => 'a b c d$@search e f g h', 'expected' => ''), array('input' => 'a b c d search$@e f g h', 'expected' => ''), array('input' => 'a b c d$@search$@e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e f g h', 'expected' => ''), array('input' => 'b c d xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e f g', 'expected' => ''), array('input' => 'c d xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e f', 'expected' => ''), array('input' => 'a$@b c d xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e f g$@h', 'expected' => ''), array('input' => 'a b$@c d xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e f$@g h', 'expected' => ''), array('input' => 'a b c$@d xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx e$@f g h', 'expected' => ''), array('input' => 'a b c d$@xsearchx e f g h', 'expected' => ''), array('input' => 'a b c d xsearchx$@e f g h', 'expected' => ''), array('input' => 'a b c d$@xsearchx$@e f g h', 'expected' => '') ); foreach($tests as $test) { preg_match($reg,$test['input'],$res); assert($res && !empty($res[0]) && $res[0]==$test['expected'], $test['input']); }