Modifying List of String in scala

Question

I have input file i would like to read a scala stream and then modify each record and then output the file.

My input is as follows -

Name,id,phone-number
abc,1,234567
dcf,2,345334

I want to change the above input as follows -

Name,id,phone-number
    testabc,test1,test234567
    testdcf,test2,test345334

I am trying to read a file as scala stream as follows:

val inputList = Source.fromFile("/test.csv")("ISO-8859-1").getLines

after the above step i get Iterator[String]

val newList = inputList.map{line => 
              line.split(',').map{s =>
                "test" + s
              }.mkString (",")
          }.toList

but the new list is empty. I am not sure if i can define an empty list and empty array and then append the modified record to the list. Any suggestions?

i am able to read the file. but i am stuck with modifying the data.the following code - val newList = inputList.map{line => line.split(',').map{s => println("test" + s) } } — user1122
– user1122, Commented Feb 14, 2017 at 16:34
yes, thats correct. this was the problem. as soon as removed the inputlist.println() from the code. It worked. Thanks! I should change the iterator to list. — user1122
– user1122, Commented Feb 14, 2017 at 16:45

NetanelRabinowitz · Accepted Answer · 2017-02-14 21:37:27Z

1

You might want to transform the iterator into a stream

val l = Source.fromFile("test.csv")
    .getLines()
    .toStream
    .tail
    .map { row =>
      row.split(',')
        .map { col =>
         s"test$col"
        }.mkString (",")
     }

  l.foreach(println)

testabc,test1,test234567

testdcf,test2,test345334

edited Feb 14, 2017 at 21:37

answered Feb 14, 2017 at 21:24

NetanelRabinowitz

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Brian · Accepted Answer · 2017-02-14 16:56:05Z

1

Here's a similar approach that returns a List[Array[String]]. You can use mkString, toString, or similar if you want a String returned.

scala> scala.io.Source.fromFile("data.txt")
  .getLines.drop(1)
  .map(l => l.split(",").map(x => "test" + x)).toList

res3: List[Array[String]] = List(
  Array(testabc, test1, test234567), 
  Array(testdcf, test2, test345334)
)

edited Feb 14, 2017 at 16:56

answered Feb 14, 2017 at 16:48

Brian

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