CODEWITHSUNDEEP
javascalarecursionsetruntimeexception
mmazepa
mmazepa

Reputation: 3

Scala, common part (intersection) of words in the list using sets

I want to define function in Scala with recursion which returns set of letters which is present in all words from the list.

For example:

    val l = List("rak","krab","krab","bark","mucha","mucha","trakty")

Should return something like:

    Set('a')

[UPDATED] My code looks as follows:

    object Program {
        def main(args: Array[String]): Unit = {

            val l = List("rak","krab","krab","bark","mucha","mucha","trakty")

            def inAll(lista: List[String]): Set[Char] = l match {
                case Nil => Set()
                case n :: Nil => n.toSet
                case n :: n2 => n.toSet & inAll(n2)
            }

            println(inAll(l))
        }
    }

While I want to display what function returns by printing the execution of it

    println(inAll(l))

then I get the RuntimeException. I've been searching the Net for hours how to solve this, but I haven't found the answer. I found something like this, but it's not enough.

The error I get is:

    java.lang.RuntimeException: Nonzero exit code: 1
        at scala.sys.package$.error(package.scala:27)
        at sbt.BuildCommon$$anonfun$toError$1.apply(Defaults.scala:2128)
        at sbt.BuildCommon$$anonfun$toError$1.apply(Defaults.scala:2128)
        at scala.Option.foreach(Option.scala:236)
        at sbt.BuildCommon$class.toError(Defaults.scala:2128)
        at sbt.Defaults$.toError(Defaults.scala:39)
        at sbt.Defaults$$anonfun$runTask$1$$anonfun$apply$46$$anonfun$apply$47.apply(Defaults.scala:769)
        at sbt.Defaults$$anonfun$runTask$1$$anonfun$apply$46$$anonfun$apply$47.apply(Defaults.scala:767)
        at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
        at sbt.$tilde$greater$$anonfun$$u2219$1.apply(TypeFunctions.scala:40)
        at sbt.std.Transform$$anon$4.work(System.scala:63)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
        at sbt.Execute.work(Execute.scala:237)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:159)
        at sbt.CompletionService$$anon$2.call(CompletionService.scala:28)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
    [error] (compile:run) Nonzero exit code: 1

I think there is something wrong in the line in which I want to recursively intersect all words from a list by calling the function inAll with parameter n2.

    case n :: n2 => n.toSet & inAll(n2)

This exception is when I try to run my program, there is no errors when I compile it.

[UPDATED] I compile program using

    compile

in SBT. And run it by

    run

also in SBT.

Upvotes: 0

Views: 174

Answers (1)

retrospectacus
retrospectacus

Reputation: 2586

Your inAll function is using l to match instead of the function's argument lista.

This appears would cause a stack overflow or out-of-memory exception and crash the program.

Upvotes: 1

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