title: Substring in Ruby
body: <p>How do I get the <code>access_token</code> value from this string?</p>
  
  <p><strong>Input string</strong>:</p>
  
  <pre><code>{\"token_type\":\"Bearer\",\"expires_in\":3600,\"access_token\":\"xb5Q4IFN4jWjRDxwFyjgWdBQpv4l\"}
  </code></pre>
  
  <p><strong>Desired output</strong>: </p>
  
  <pre><code>"TQdcdvvPZTEtPMj7s8urQIg90y8g"
  </code></pre>
  
  <p>Is there a good reference for finding the solution?</p>