 over <code>self</code>.</p>

<pre><code class="language-swift">s.flatMap(transform)</code></pre>

<p>is equivalent to</p>

<pre><code class="language-swift">Array(s.map(transform).flatten())</code></pre>

<p><strong>Complexity:</strong> O(<em>M</em> + <em>N</em>), where <em>M</em> is the length of <code>self</code>
  and <em>N</em> is the length of the result.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">func flatMap&lt;S : SequenceType&gt;(transform: (Base._Element) throws -&gt; S) r