如何从Scala中的数据数组获取地图

Question

i am a newbie in scala, here i have an array variable call colarr

colarr: Array[(String, String)] = Array((empid,IntegerType), (empname,StringType), (address,StringType), (salary,IntegerType), (doj,TimestampType))

how to get individual value like empid and IntergerType from it?

Answer 1

If you want to go over each tuple, you can use Array.foreach :

scala> val arr = Array(("hello", "world"), ("this", "isnice"), ("yay", "it works"))
scala> arr.foreach { 
        case (first, second) => println(s"First element $first, Second element: $second") }

First element hello, Second element: world
First element this, Second element: isnice
First element yay, Second element: it works

If you want to project a value from each tuple, you can use Array.map :

scala> arr.map { case (first, second) => s"$first, $second" }
res1: Array[String] = Array(hello, world, this, isnice, yay, it works)

The case (first, second) is just syntax for creating a partial function which allows you to extract the first and second element from the tuple.

If you want something simpler for starters, you can a total function and work with _.1 and _.2 elements of the tuple:

scala> arr.map(tuple => s"${tuple._1}, ${tuple._2}")
res2: Array[String] = Array(hello, world, this, isnice, yay, it works)