title: Does Ruby regular expression have a not match operator like "!~" in Perl?
body: <p>I just want to know whether ruby regex has a not match operator just like <code>!~</code> in perl. I feel it's inconvenient to use <code>(?!xxx)</code>or <code>(?&lt;!xxxx)</code> because you cannot use regex patterns in the <code>xxx</code> part. </p>