title: Basic regex for 16 digit numbers
body: <p>I currently have a regex that pulls up a 16 digit number from a file e.g.:</p>
  
  <p>Regex:</p>
  
  <pre><code>Regex.Match(l, @"\d{16}")
  </code></pre>
  
  <p>This would work well for a number as follows:</p>
  
  <blockquote>
    <p>1234567891234567</p>
  </blockquote>
  
  <p>Although how could I also include numbers in the regex such as:</p>
  
  <blockquote>
    <p>1234 5678 9123 4567</p>
  </blockquote>
  
  <p>and</p>
  
  <blockquote>
    <p>1234-5678-9123-4567</p>
  </blockquote>