title: KeyError: "[Column] not found in axis"
body: <p>If a column exists between 2 dataframes, I want to drop it. I check if it exists and then try to drop it, but then it says that can't be found.</p>
  
  <pre><code>for column in positionsdf.columns:
      if column in entrydf.columns:
          entrydf = entrydf.drop(column)
  </code></pre>
  
  <p>error:</p>
  
  <pre><code>---------------------------------------------------------------------------
  KeyError                                  Traceback (most recent call last)
  &lt;ipython-input-20-d9893719abf8&gt; in &lt;module&gt;
        1 for column in positionsdf.columns:
        2     if column in entrydf.columns:
  ----&gt; 3         entrydf = entrydf.drop(column)
  
  ...
  ...
  ...
  
  KeyError: "['caseworker'] not found in axis"
  </code></pre>