Iterating over numbers with leading zeroes with a `for` loop
<p>I'm working on a calendar site and need to change the following code to show <code>0</code> before the value of <code>$list_day</code> if it's a single digit number. </p>

<pre><code>for($list_day = 1; $list_day &lt;= $days_in_month; $list_day++):
</code></pre>

<p>How should I go about doing this?</p>
