Given a python dictionary, most efficient means to extract keys that start with a string pattern
<p>Lets say I have a python dictionary:</p>

<pre><code>{'i:crid1':1, 'c:crid1':1, 'i:crid2':1, 'c:crid2':1....}
</code></pre>

<p>What is the most elegant way in python to just extract all keys that begin with c:?</p>

<pre><code>{'c:crid1':1,'c:crid2':1....}
</code></pre>

<p>Speed is of the utmost importance and can be a big dict.  Maybe weave is a candidate tool.</p>

<p>I added this comment.  The dicts come from redis.  No choice about the data structure... that being said.  I need speed.  Not elegance. </p>
