Append Map[String, String]() onto an Array or List with [String] type in Scala

Question

I have stored my key, value pairs in multiple Mutable Map with MapString, String. And I can see the key and values in it. However, now I need to append these maps onto ArrayBuffer or List with String Type in Scala. So that, I can loop over every element in Array and proceed further. Please help.

Sample Code.

val X= scala.collection.mutable.Map[String, String]()

  X += ("Name" -> "Raghav")
  X += ("Home" -> "Gurgaon")

val Y= scala.collection.mutable.Map[String, String]()

  Y += ("Name" -> "Vikrant")
  Y += ("Home" -> "Noida")

var JobConfigs = scala.collection.mutable.ArrayBuffer.empty[String]

JobConfigs += X
JobConfigs += Y

Answer 1

From your comment:

its throwing issue - for (e <- JobConfigs) { for ((k, v) <- e) { println("Key:" + k + ", Value:" + v) } }

This doesn't make sense; because your JobConfigs is an ArrayBuffer[String] , e will be a String and doesn't contain any pairs. It will work, with no other changes, if you change the type of JobConfigs :

var JobConfigs = scala.collection.mutable.ArrayBuffer.empty[Map[String, String]]

Alternatively, you could have

var JobConfigs = scala.collection.mutable.ArrayBuffer.empty[(String, String)]
JobConfigs ++= X
JobConfigs ++= Y

for ((k, v) <- JobConfigs) { println("Key:" + k + ", Value:" + v) }

Side notes:

1. JobConfigs should be declared as val , unless you later do JobConfigs =... . Even if you do, it's often not a good idea.

2. Idiomatic names for local variables start with a lower-case letter: x , y , jobConfigs .

Answer 2

The following code will add an immutable object of Map to ArrayBuffer.

JobConfigs += X

You can try to insert an mutable object like this:

JobConfigs.append(X.toMap)

Not sure why you want to convert the map to string, I would suggest you keep it a Map which is better for accessing the values. But here is a snippet to convert a map to String:

Map("ss" -> "yy", "aa" -> "bb").map{case (k, v) => k + ":" + v}.mkString("|")

Hope this helps. Good luck.

Answer 3

Another approach using case classes.

case class Person(Name: String, Home: String)

var JobConfig = scala.collection.mutable.ArrayBuffer[Person]()

JobConfig += Person("Raghav", "Gurgaon")
JobConfig += Person("Vikrant", "Noida")

for(i <- JobConfig){
  println(s"home :${i.Home} , name : ${i.Name}")
}

Output: 
home :Gurgaon , name : Raghav
home :Noida , name : Vikrant