Scala - how to get a list element

Question

I'm trying to get element from a list:

data =List(("2001",13.1),("2009",3.1),("2004",24.0),("2011",1.11))

Any help? Task is to print separatly Strings and numbers like:

print(x._1+" "+x._2) 

but this is not working.

Answer 1

One good practice with functional programming is to do as much as possible with side-effect-free transformations of immutable objects.

What that means (in this case) is that you can convert the list of tuples to a list of strings, then limit your side-effect (the println ) to a single step at the very end.

val data = List(("2001",13.1),("2009",3.1),("2004",24.0),("2011",1.11))
val lines = data map { case(a,b) => a + " " + b.toString }
println(lines mkString "\n") 

Answer 2

scala> val data =List(("2001",13.1),("2009",3.1),("2004",24.0),("2011",1.11))
data: List[(java.lang.String, Double)] = List((2001,13.1), (2009,3.1), (2004,24.0), (2011,1.11))

scala> data.foreach(x => println(x._1+" "+x._2))
2001 13.1
2009 3.1
2004 24.0
2011 1.11

Answer 3

val list = List(("2001",13.1),("2009",3.1),("2004",24.0),("2011",1.11))
println(list map (_.productIterator mkString " ") mkString "\n")

2001 13.1
2009 3.1
2004 24.0
2011 1.11

Answer 4

我将使用模式匹配，从而产生一种编程模式，该模式可以更好地缩放以用于更大的元组和更复杂的元素：

data.foreach { case (b,c) => println(b + " " + c) }

Answer 5

for the Strings, use

List((1,"aoeu")).foreach(((_:Tuple2[String,_])._1) andThen print)

for the numbers, use

 List(("aoeu",13.0)).foreach((( _ :Tuple2[ _ ,Double])._2) andThen print)