title: Adding new element within a list inside a dictionary
body: <p>In a dictionary, I want to add a list of numbers for a given key.But I am unable to do it.</p>
  
  <pre><code>for(int i = 0 ; i &lt; size ; i++){
     string input = Console.ReadLine();
     string[] inputList = input.Split(' ');
     count[Convert.ToInt32(inputList[0])]++;
     if(!map.ContainsKey(Convert.ToInt32(inputList[0]))){
       map.Add(Convert.ToInt32(inputList[0]),new List&lt;string&gt;());
       map_index.Add(Convert.ToInt32(inputList[0]),new List&lt;int&gt;());
     }
  }
  </code></pre>