How do I change this code to be functional programming in scala?

Question

I'm new to functional programming and as I'm reading this book. It basically says that if you code contains "var" it means that you're still doing in a imperative way. I'm not sure how do I change my code to be functional way. Please suggests.

So basically what this code does is to processText some text and use regular expression to extract a particular text from "taggedText" and add that to a list and convert the list to json.

    val text = params("text")
    val pattern = """(\w+)/ORGANIZATION""".r

    var list = List[String]()
    val taggedText = processText(text)
    pattern.findAllIn(taggedText).matchData foreach {
      m => list ::= m.group(1)
    }

    pretty(render(list)) // render to json

Answer 1

Try replacing the middle section with

val list = pattern.findAllIn(taggedText).matchData.map(m => m.group(1)).toList

You can write m => m.group(1) as _.group(1) if you want.