title: Select Specific Rows in Deedle
body: <p>I have a deedle data frame, called df, with one of the columns named <code>TimeSpent</code>.</p>
  
  <p>I would like to keep the rows, which have values for <code>TimeSpent</code> greater than a specific TimeSpan (e.g. 30 minutes). 
  I could only manage to keep the rows with a specific <code>TimeSpan (30 min)</code> by using <code>FilterRowsBy()</code></p>
  
  <pre><code>df = df.FilterRowsBy&lt;int, string, TimeSpan&gt;("TimeSpent", new TimeSpan(0, 30, 0));
  </code></pre>
  
  <p>How do you filter a deedle data frame for a certain range?</p>
  
  <p>UPDATE: So, I decided to try to sort the deedle frame by <code>TimeSpan</code> first, and then slice it.</p>
  
  <pre><code>Frame&lt;TimeSpan, string&gt; dfTest = df.IndexRows&lt;TimeSpan&gt;("TimeSpent").SortRowsByKey();
  var dfTest2 = dfTest.Rows.After(twentyMin);
  </code></pre>
  
  <p>And as a result I get a new data frame that is type <code>&lt;TimeSpan, ObjectSeries&lt;System.String&gt;&gt;</code>, but I need to convert this data frame to <code>&lt;TimeSpan, String&gt;</code>, and I do not know how. </p>