title: How to update an element with a List using LINQ and C#
body: <p>I have a list of objects and I'd like to update a particular member variable within one of the objects. I understand LINQ is designed for query and not meant to update lists of immutable data. What would be the best way to accomplish this? I do not need to use LINQ for the solution if it is not most efficient. </p>
  
  <p>Would creating an Update extension method work? If so how would I go about doing that?</p>
  
  <pre><code>EXAMPLE:
  (from trade in CrudeBalancedList
   where trade.Date.Month == monthIndex
   select trade).Update(
   trade =&gt; trade.Buy += optionQty);
  </code></pre>