title: Find and remove matching column values in pyspark
body: <p>I have a pyspark dataframe where occasionally the columns will have a wrong value that matches another column. It would look something like this:</p>
  
  <pre><code>| Date         | Latitude      |
  | 2017-01-01   | 43.4553       |
  | 2017-01-02   | 42.9399       |
  | 2017-01-03   | 43.0091       |
  | 2017-01-04   | 2017-01-04    |
  </code></pre>
  
  <p>Obviously, the last Latitude value is incorrect. I need to remove any and all rows that are like this. I thought about using <code>.isin()</code> but I can't seem to get it to work. If I try</p>
  
  <pre><code>df['Date'].isin(['Latitude'])
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>Column&lt;(Date IN (Latitude))&gt;
  </code></pre>
  
  <p>Any suggestions?</p>