Exporting list to .csv [Scala]

Question

I am new to Scala and programming in general. How would I go to write a list into a .csv file using Scala?

So I have a list of objects...

List[test] = List(test(Group1,lol,1,2,3),test(Group2,lel,4,5,6)....)

how would I export it to a .csv with 4 columns, and each line having the attributes of an object?

Any help is appreciated.

Because of so many issues, even in the presence of an RFC for the .csv MIME-type, I strongly suggest you use a well-maintained RFC driven native Scala library which optimally handles this problem, kantan.csv: nrinaudo.github.io/kantan.csv — chaotic3quilibrium
– chaotic3quilibrium, Commented Aug 30, 2020 at 20:25

Dima · Accepted Answer · 2017-12-09 16:24:41Z

2

Case classes are instances of Product that offers a nice way to iterate through all of the fields as .productIterator.

The idea is that you convert all fields to strings, then escape backslashes and double-quotes if there are any, then join them all together, double-quoted and separated by commas, and then glue everything with a new-line:

list
 .map { 
    _.productIterator
     .map(_.toString)
     .map(_.replaceAll("\\", "\\\\"))
     .map(_.replaceAll("\"", "\\\""))
     .mkString("\"", "\",\"", "\"")
 }.mkString("\n")

answered Dec 9, 2017 at 16:24

Dima

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Comments

Conor Fennell · Accepted Answer · 2017-12-09 14:57:16Z

0

I recommend using an existing library: https://github.com/melrief/PureCSV
Use SBT for resolving the dependency: http://www.scala-sbt.org/
Files:
* ./build.sbt
* ./OutputCsv.scala

build.sbt

name := "parse-csv"
version := "1.0.0"
libraryDependencies ++= Seq("com.github.melrief" %% "purecsv" % "0.1.1")

OutputCsv.scala

import purecsv.safe._

object OutputCsv extends App {
    case class Test(group: String, message: String, age: Int)
    val tests = List(Test("Group1", "lol", 1), Test("Group2", "lel", 4))

    println(tests.toCSV()) // just for debug purposes
    tests.writeCSVToFileName("/tmp/example.csv", header=Some(Seq("group", "message", "age")))
}

sbt run will execute the file

answered Dec 9, 2017 at 14:57

Conor Fennell

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1 Comment

Batman Begins Over a year ago

That is great feedback! I have managed everything you mention except the sbt run part. I am using IntelliJ here and when running the code I only get import purecsv.safe._ defined module OutputCsv So I suppose it does not run

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