What is the most efficient way to search nested lists in python?
<p>I have a list that contains nested lists and I need to know the most efficient way to search within those nested lists.</p>

<p>e.g., if I have </p>

<pre><code>[['a','b','c'],
['d','e','f']]
</code></pre>

<p>and I have to search the entire list above, what is the most efficient way to find 'd'?</p>
