title: How can find specific HashSet elements with linq
body: <p>I have HashSet of array of strings. One string of array is like "2015-9-14 21:22:13" DateTime. How can convert with DateTime.ParseExact to be dateTime and then find all times from HashSet arrays between two dateTimes using linq. Before I used list but HashSet is have better performance when is search element, and now I change my code to work with HashSet.</p>
  
  <p>Here is my old code with list:</p>
  
  <pre><code>foreach (var infos in this.InfoFromDatabase)
          {
              thisTime = DateTime.ParseExact(infos[5], "yyyy-M-d H:m:s", null);
  
              // if is in this diapazon time add in list
              if (thisTime &gt; minimumDateTime &amp;&amp; thisTime &lt; maximumDateTime)
              {
                  allInformation.Add(infos);
              }
          }
  </code></pre>