title: Why won't the exp function work in pyspark?
body: <p>I'm trying to calculate odds ratios from the coefficients of a logistic regression but I'm encountering a problem best summed up by this code:</p>
  
  <pre><code>import pyspark.sql.functions as F 
  F.exp(1.2)
  </code></pre>
  
  <p>This fails with <code>
  py4j.Py4JException: Method exp([class java.lang.Double]) does not exist</code></p>
  
  <p>An integer fails similarly. I don't get how a Double can cause a problem for the exp function? </p>