title: Get all values between delimiters in large string
body: <p>I have a string that has bunch of text. I need to locate all values that are located between
  'site.com/PI/' and '/500/item.jpg</p>
  
  <p>Example:</p>
  
  <pre><code>String STRING = @"
  http://site.com/PI/0/500/item.jpg
  blah-blah
  http://site.com/PI/1/500/item.jpg
  blah-blah
  http://site.com/PI/2/500/item.jpg
  blah-blah
  http://site.com/PI/4/500/item.jpg
  blah-blah
  http://site.com/PI/8/500/item.jpg
  blah-blah
  http://site.com/PI/6/500/item.jpg    blah-blah"
  </code></pre>
  
  <p>need to get list of { 0, 1, 2, 4, 8, 6 }</p>
  
  <p>It is easy to get one occurence using regex:</p>
  
  <pre><code>Regex.Match(STRING, @"(?&lt;=/PI/).*(?=/500/)").Value;
  </code></pre>
  
  <p>How can I get all occurencies into one list?</p>