Performance - 3 ways to implement a regex character set?
<p>It seems there are 3 main ways.</p>

<p>Explicitly stating characters,</p>

<pre><code>[a-zA-z0-9_]
</code></pre>

<p>Using a shortcut,</p>

<pre><code>[\w]
</code></pre>

<p>and using ASCI or some other encoding,</p>

<pre><code>[\x20-\x7E],
</code></pre>

<p>Which is fastest, or is it just a matter of style?</p>
