title: How to handle an index out of bounds error?
body: <p>What is the idiomatic way to handle this to avoid a runtime error:</p>
  <pre><code>let address = match x[1].parse::&lt;String&gt;() {
      Ok(a) =&gt; Some(a),
      Err(_) =&gt; None,
  };
  </code></pre>
  <p>Where <code>x[1]</code> could panic with an <code>index out of bounds</code> error?</p>