should only be called after <code>this.<a href="#match">match</a></code> or
<code>this.<a href="#matchSub">matchSub</a></code>, and then operates on the String of that operation.</p>
<p>The index <code>n</code> corresponds to the n-th set of parentheses in the pattern
of <code>this</code> EReg. If no such sub-group exists, an exception is thrown.</p>
<p>If <code>n</code> equals 0, the whole matched substring is returned.</p></div></div><div class="platform platform-haxe-ui-toolkit"><a name="matchedLeft"></a