Slicing lists and strings to negative zero
<p>I've read the <a href="http://docs.python.org/tutorial/introduction.html#strings" rel="nofollow">Python informal tutorial</a> on slicing, which all makes sense to me except for one edge case. It seems like</p>

<pre><code>'help'[:-0]
</code></pre>

<p>should evaluate to <code>'help'</code>, but it really evaluates to <code>''</code>. What's a good way to think about negative index slicing so that this particular edge case makes sense?</p>
