title: The most elegant way to collect nonEmpty object fields from the list of objects
body: <p>I have a list of objects, for example</p>
  
  <pre><code>case class MyClass(paramA: Option[String], paramB: String)
  
  val myList = List[MyClass]
  </code></pre>
  
  <p>I need to make a new List[String] which contains nonEmpty paramA values from myList. For example,</p>
  
  <pre><code>val myList = List(MyClass(None,"abc"),
                    MyClass("AAA","xyz"), 
                    MyClass("BBB","xyz"))
  
  //the result must be List("AAA","BBB")
  </code></pre>
  
  <p>What is the most elegant way to do that?</p>