Scala Cookbook

12.5. How to Process a CSV File

Problem

You want to process the lines in a CSV file, either handling one line at a time or storing them in a two-dimensional array.

Solution

Combine Recipe 12.1 with Recipe 1.3. Given a simple CSV file like this named finance.csv:

January, 10000.00, 9000.00, 1000.00
February, 11000.00, 9500.00, 1500.00
March, 12000.00, 10000.00, 2000.00

you can process the lines in the file with the following code:

object CSVDemo extends App {

  println("Month, Income, Expenses, Profit")
  val bufferedSource = io.Source.fromFile("/tmp/finance.csv")
  for (line <- bufferedSource.getLines) {
    val cols = line.split(",").map(_.trim)
    // do whatever you want with the columns here
    println(s"${cols(0)}|${cols(1)}|${cols(2)}|${cols(3)}")
  }
  bufferedSource.close

}

The magic in that code is this line:

val cols = line.split(",").map(_.trim)

It splits each line using the comma as a field separator character, and then uses the map method to trim each field to remove leading and trailing blank spaces. The resulting output looks like this:

January|10000.00|9000.00|1000.00
February|11000.00|9500.00|1500.00
March|12000.00|10000.00|2000.00

If you prefer named variables instead of accessing array elements, you can change the for loop to look like this:

for (line <- bufferedSource.getLines) {
  val Array(month, revenue, expenses, profit) = line.split(",").map(_.trim)
  println(s"$month $revenue $expenses $profit")
}

If the first line of the file is a header line and you want to skip it, just add drop(1) after ...