title: rename columns in dataframe pyspark adding a string
body: <p>I have written code in Python using Pandas that adds "VEN_" to the beginning of the column names:</p>
  
  <pre><code>Tablon.columns = "VEN_" + Tablon.columns
  </code></pre>
  
  <p>And it works fine,  but now I'm working with PySpark and it doesn't work.
  I've tried:</p>
  
  <pre><code>Vaa_total.columns = ['Vaa_' + col for col in Vaa_total.columns]
  </code></pre>
  
  <p>or </p>
  
  <pre><code>for elemento in Vaa_total.columns:
      elemento = "Vaa_" + elemento
  </code></pre>
  
  <p>And other things like that but it doesn't work.</p>
  
  <p>I don't want to replace the columns name, I just want to mantain it but adding a string to the beginning.</p>