使用嵌套函数过滤压缩数组期间的编译错误

Question

I'm trying to filter zipped arrays using nested function, but I have got a compilation error related to the type of the variable "mergedRow"

Here is my example :

ScalaVersion = 2.10.4

val arrayOne : Seq[IndexedSeq[Double]] = Seq.empty
val arrayTow : Seq[IndexedSeq[String]]  = Seq.empty

(this.arrayOne , this.arrayTow).zipped.filter{
  mergedRow : (IndexedSeq[String], IndexedSeq[Double])=>

  // some processing
  true
}

The compilation error :

Error:(130, 51) type mismatch;
 found   : ((IndexedSeq[String], IndexedSeq[Double])) => Boolean
 required: (IndexedSeq[String], IndexedSeq[Double]) => Boolean
      mergedRow : (IndexedSeq[String], IndexedSeq[Double])=>
                                              ^

I don't know the origin of this error, so every help will be appreciated.

Cheers.

Answer 1

You're missing case . It should look more like this:

(arrayOne , arrayTwo).zipped.filter{
    case (one, two) =>
       // filter predicate
}

The type arguments will produce a fruitless type test warning, so I omitted them. You can replace case (one, two) with case mergedRow if you wish, but doing operations on one and two is much cleaner than mergedRow._1 and mergedRow._2 .