title: How to run a LINQ query on a collection of objects and a collection inside of each object
body: <p>I have a collection of objects where each object also has a collection. Like so:</p>
  
  <pre><code>public class Product
  {
      public int Id { get; set; }
      public List&lt;Tuple&lt;string, double&gt;&gt; Sales { get; set; }
  }
  </code></pre>
  
  <p>I want to run a LINQ query to check if a Product entity exists and, if it does exist, check it's Sales collection to see if a specific string value (from the Tuple) also exists. If it does, I want to return the corresponding double (also from the Tuple).</p>
  
  <p>I know I can do this in a few lines of code, like so:</p>
  
  <pre><code>saleAmount = String.Empty;                      
  product = Model.Products.SingleOrDefault(p =&gt; p.Id == product.Id);
  if(product != null)
  {
      productSale = product.Sales.SingleOrDefault(i =&gt; i.Item1 == sale.Id);
      if(productSale != null)
      {
          saleAmount = productSale.Item2.ToString();
      }
  }
  </code></pre>
  
  <p>Is it possible to do this in one line?</p>