title: Create and set an element of a Pandas DataFrame to a list
body: <p>I have a Pandas DataFrame that I'm creating row-by-row (I know, I know, it's not Pandorable/Pythonic..). I'm creating elements using <em>.loc</em> like so</p>
  
  <pre><code>output.loc[row_id, col_id]
  </code></pre>
  
  <p>and I'd like to set this value to an empty list, []. </p>
  
  <pre><code>output.loc[row_id, col_id] = []
  </code></pre>
  
  <p>Unfortunately, I get an error saying the size of my keys and values do not match (Pandas thinks I'm trying to set values <em>with</em> not <em>to</em> an iterable).</p>
  
  <p>Is there a way to do this?</p>
  
  <p>Thanks!</p>