title: What is the fastest way to conditionally update data in a DataTable?
body: <p>I have DataTable full of data, with 3 columns - <code>col1</code>, <code>col2</code>, and <code>col3</code>.</p>
  
  <p>I have to update data in <code>col3</code> (set it to <code>null</code>) when the value in <code>col3</code> is greater than 1000 or less than -1000.  I tried to iterate each row and check this condition, but it is too slow.  How do I improve the speed?</p>