Scala Convert List of Strings to Ints, List[String] => List[Int]

I am still fairly new to Scala so take what I write in this article with a grain of salt.

The more I learn Scala to more I like it and here is an example of why…

The following Scala Code will read in a file (whos name is the first command line argument) and read in every line as a String Array, convert it to a List[String] then convert that to a List[Int]  (this assumes the file has a valid integer on each line.  Then it prints out the Int list adding +1 to each number as it prints it out.

import scala.io.Source object ListStringToInt{   def main(args: Array[String]) {     val sList = Source.fromFile(args(0)).       getLines.toList.map((s: String) => s.toInt)     sList.foreach((x: Int) => println(x + 1))   } }

I like this line, it simple and short.

val sList = Source.fromFile(args(0)).       getLines.toList.map((s: String) => s.toInt)

Going over it bit by bit

Read from a file

Source.fromFile(args(0))

Get the Lines from the file and convert them into a list, this is a List of Strings

getLines.toList.

Take the List of Strings and convert it to a List of Ints by running each String in the list through the function (s: String) => s.toInt

.map((s: String) => s.toInt)

This portion of the code can be further simplified by writing it in the following way

.map(_.toInt)

Cleaning up the rest of the code you get the following

import scala.io.Source /**  * Created by patman on 5/12/2014.  */ object ListStringToInt{   def main(args: Array[String]) {     val sList = Source.fromFile(args(0)).getLines.toList.map(_.toInt)     sList.foreach(x => println(x + 1))   } }

I think this simple one liner is very effective and easy to read once you become a little familiar with Scala (I am by no means an expert yet)

I have been guilty of creating one liners in code that, though they are concise, are difficult to read.  I think the Scala language and libraries do a very good job in making readable one liners.

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