title: List<int> separated into thirds
body: <p>Assuming I have a list of numbers, which could be any amount, realistically over 15.</p>
  
  <p>I want to separate that list of numbers into three groups depending on their size, small, medium, and large for instance.</p>
  
  <p>What is the best way of achieving this?</p>
  
  <p>I've written out the below, is it necessary to make my own function as per below, or is there anything existing that I can utilise in .NET?</p>
  
  <pre><code>  public static List&lt;int&gt; OrderByThree (List&lt;int&gt; list)
              {
                  list.Sort();
                  int n = list.Count();
                  int small = n / 3;
                  int medium = (2 * n) / 3;
                  int large = n;
      // depending if the number is lower/higher than s/m/l,
   // chuck into group via series of if statements
  
                  return list;
              }
  </code></pre>
  
  <p><strong>Example</strong>
  Say I have a list of numbers, 1-15 for instance, I want 1-5 in small, 6-10 in medium and 11-15 in large. However I won't know the amount of numbers at the start, no dramas, using <code>list.count</code> I was hoping to divide for my own function.</p>