Update string in List
<p>I have loaded a txt comma delimited into multiple lists. For example</p>

<pre><code>static public void File()    
{    
    var order_no = new List&lt;String&gt;();    
    var quantity = new List&lt;String&gt;();    
    order_no.Add(fields[0]);    
    quantity.Add(fields[1]);    
}       
</code></pre>

<p>Now what i am trying to is in a loop while the same order is found down the list and the quantity is null then update the quantity in the previous.  </p>

<p>For example</p>

<blockquote>
  <p>order NO : 1     quantity: null</p>
  
  <p>order NO : 5     quantity: 2</p>
  
  <p>order no : 1     quantity: 1</p>
</blockquote>

<p>what it should do is to update the quantity in the first value to 1.</p>

<p>How can i accomplish that?</p>
