title: F# how to handle nullable types
body: <p>I try to do some graphs in F#. As an input I have CSV file that has some values nullable (e.g. nullable int). I try to show chart with following code :</p>
  
  <pre><code>[for row in data.Rows -&gt; row.A.Value, row.B.Value] |&gt; Chart.Point
  </code></pre>
  
  <p>Where both A and B are nullable integers. I received following error </p>
  
  <blockquote>
    <p>System.InvalidOperationException: Nullable object must have a value.</p>
  </blockquote>
  
  <p>How I should handle nullable types. Should I write some Option type to handle it or there is some other good way how to solve it.</p>