title: Pyspark : select specific column with its position
body: <p>I would like to know how to select a specific column with its number but not with its name in a dataframe ?</p>
  
  <p>Like this in Pandas:</p>
  
  <pre><code>df = df.iloc[:,2]
  </code></pre>
  
  <p>It's possible ?</p>