Learning index of "for-in loop"
<p>I have a list and it contains lists. The inner lists are may be empty. This is the structure:</p>

<pre><code>[[],[a,b],[],[c],[d]]
</code></pre>

<p>My code:</p>

<pre><code>for inner in list:
   for char in inner:
      print char           # I want to add indexes of inner lists here
</code></pre>

<p>Output is:</p>

<pre><code>abcd
</code></pre>

<p>I want the output to be:</p>

<pre><code>2a2b4c5d
</code></pre>

<p>The numbers are indexes of inner lists. Is there quick way to do this?</p>
