Python: Dividing a string into substrings
<p>I have a bunch of mathematical expressions stored as strings. Here's a short one:</p>

<pre><code>stringy = "((2+2)-(3+5)-6)"
</code></pre>

<p>I want to break this string up into a list that contains ONLY the information in each "sub-parenthetical phrase" (I'm sure there's a better way to phrase that.) So my yield would be:</p>

<pre><code>['2+2','3+5']
</code></pre>

<p>I have a couple of ideas about how to do this, but I keep running into a "okay, now what" issue.</p>

<p>For example:</p>

<pre><code>for x in stringy:
    substring = stringy[stringy.find('('+1 : stringy.find(')')+1]
    stringlist.append(substring)
</code></pre>

<p>Works just peachy to return 2+2, but that's about as far as it goes, and I am completely blanking on how to move through the remainder...</p>
