scala converting Array[String] to case class

Question

newbie question but I often found myself working with files, parsing each line and convert it into case class so that I can use if further in more object like manner. In java and now in scala I do same procedure.

case class ABC(v1: Int, v2: String)
val str = line.split("\t")
val v1 = str(0).toInt
val v2 = str(1)
ABC(v1, v2)

Is there any shorter way I can create case class from array than this? This gets very tedious as I always have tons of fields to process.

Look at product-collections library. It has nice csv to seq of case classes functionality — Odomontois
– Odomontois, Commented May 2, 2015 at 14:11

elm · Accepted Answer · 2015-05-02 19:17:30Z

6

Define an parse method in a companion object that takes a string and extracts values for constructing an instance,

import util._

case class ABC(v1: Int, v2: String)

object ABC {
  def parse(s: String): Try[ABC] = {
    val Array(v1,v2,_*) = s.split("\t")
    Try(ABC(v1.toInt, v2))
  }
}

Note v1 is converted to Int, also we extract the first two items from the split string yet any number of items may be extracted and then converted to desired types.

Then a valid use includes for instance

val v = ABC.parse("12\t ab")

edited May 2, 2015 at 19:17

answered May 2, 2015 at 1:30

elm

20.5k15 gold badges72 silver badges116 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Travis Brown Over a year ago

I'd suggest naming this something other than apply (e.g. parse), since many people will expect apply to take the case class's members directly, and definitely not to fail with an exception on normal input.

elm Over a year ago

@TravisBrown thanks, agree naming the method apply proves misleading (unintended semantics :) Please note update...

Travis Brown Over a year ago

Thanks, looks reasonable to me (I'd still prefer the result as Try[ABC], but that's more a matter of taste).

nir Over a year ago

ok so this demonstrate parsing logic in one place(object) but it doesn't buy much in my case as I iterate each file only once. I could just do ABC(arr(0).toInt, arr(1)). I agree elm suggestion is more object oriented and I will prefer that. But what I was looking for is straightforward way just to convert array's elements into case class in same order. i.e. arr(0) gets assign to first element of case class and so on. It should also do type conversion and throw compile or runtime error if it can't parse

Collectives™ on Stack Overflow

scala converting Array[String] to case class

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related