title: How can I start initialization of "List of list" with columns
body: <p>I have a list of list and I want to add values column oriented. Like in the following code sample:</p>
  
  <pre><code>Data = new List&lt;List&lt;double&gt;&gt;();
  for (int i = 0; i &lt; columnCount; i++)
          {
              for (int j = 0; j &lt; rowCount; j++)
              {
                  Data[j][i] = (probabilityList[j]) * K); // It won't work
              }
          }
  </code></pre>
  
  <p>I know it won't work because Data's index does not exist at current situation, and I need to use add() method.</p>
  
  <p>However, I need to add values to list starts with columns:</p>
  
  <pre><code>[1   , null] ----&gt; [1, null]
  [null, null]       [2, null]
  </code></pre>
  
  <p>How can I add values to a list of list starts with columns?</p>