What is a more efficient way in Python to return list elements which are not in a second list?
<p>Is there a faster way to do this in python?</p>

<pre><code>[f for f in list_1 if not f in list_2]
</code></pre>

<p>list_1 and list_2 both consist of about 120.000 strings. It takes about 4 minutes to generate the new list.</p>
