title: How to get only N first instances of char in a String column?
body: <p>I have a column with string value of <code>"x,x,x,x,x,x,x,x..."</code>. </p>
  
  <p>We would like to go over all the rows and have only N items (all others should be deleted). </p>
  
  <p>The delimiter is <code>','</code>.</p>
  
  <p>X  can have different lengths.</p>
  
  <p>How can I do it?</p>