Removing one list from another
<p>In python (2.7) we can do:</p>

<pre><code>&gt;&gt;&gt; a = [1, 2, 3]
&gt;&gt;&gt; b = [4 , 5]
&gt;&gt;&gt; a + b
[1, 2, 3, 4, 5]
</code></pre>

<p>However we can't do a - b.</p>

<p>Since python seems to have something cool for nearly everything, what is the most python-esque to do a - b, in your opinion?</p>

<p>Similar question for dictionaries, which can neither do a + b, or a - b, where a and b are both dictionaries.  Thanks.</p>
