title: Retrieve field from map array
body: <p>In a document, I have an array list. Each one contains a map which contains multiple fields like <a href="https://i.stack.imgur.com/La18Q.png" rel="nofollow noreferrer">this</a>.</p>
  
  <p>How can I retrieve a specific field from that array? For example, to retrieve "field 3", what should I do?</p>