title: What does => mean in a Linq Expression
body: <p>*Although this is a duplicate question, I had never seen the expression "=>" in code before. If I had known this was specifically a lambda expression, I would have google'd and figured it out on my own. Thanks!</p>
  
  <p>I'm new to using Linq, so the use of "=>" really confused me when I ran across it in this code:</p>
  
  <pre><code>using System;
  using System.Linq;
  using System.Collections.Generic;
  
  public static class Extend
  {
      public static double StandardDeviation(this IEnumerable&lt;double&gt; values)
      {
          double avg = values.Average();
          return Math.Sqrt(values.Average(v=&gt;Math.Pow(v-avg,2)));
      }
  }
  </code></pre>
  
  <p>Source: <a href="https://stackoverflow.com/questions/3141692/standard-deviation-of-generic-list">Standard deviation of generic list?</a></p>
  
  <p>A few questions:
  What does => do here?
  Intellisense tells me that 'v' is an int, but it was never declared. How does this work?</p>