How to transform Array[(String,List[String])] to Array[(String,String)]

Question

Suppose i am having mapping in following way :

[ (1,List[11,12,13]),(2,List[21,22,23]),(3,List[31,32,33]) ]

i want to convert/transform this in the form shown below :

[ (1,11),(1,12),(1,13),(2,21),(2,22),(2,23),(3,31),(3,32),(3,33)]

I am using scala 2.10.4

vitalii · Accepted Answer · 2016-02-25 12:35:34Z

7

Use flatMap:

 val xs = Array( (1,List(11,12,13)),(2,List(21,22,23)),(3,List(31,32,33)) )
 xs.flatMap{ case (s, xs) => xs.map((s,_))}

answered Feb 25, 2016 at 12:35

vitalii

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cchantep · Accepted Answer · 2016-02-25 12:35:39Z

6

You can try:

array.flatMap { case (key, arr) => arr.map { key -> _ } }

answered Feb 25, 2016 at 12:35

cchantep

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hasumedic · Accepted Answer · 2016-02-25 12:38:17Z

3

A solution using for comprehension:

val input = List((1,List(11,12,13)),(2,List(21,22,23)),(3,List(31,32,33)))

val output = for {
  tuple <- input
  element <- tuple._2
} yield (tuple._1, element)

answered Feb 25, 2016 at 12:38

hasumedic

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Alexandr Dorokhin · Accepted Answer · 2016-02-25 12:55:40Z

2

Maybe you would like this:

for {
   (k,arr) <- arrOfTuple
   el <- arr
 } yield (k -> el)

answered Feb 25, 2016 at 12:55

Alexandr Dorokhin

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