CODEWITHSUNDEEP
scala
jijesh Aj
jijesh Aj

Reputation: 614

Inserting iterated value to scala list

var questionList:List[Question]=null
   questionSetQuestionQuestion=questionSetQuestionService.findQuestionSetQuestionByQuestionSetId(id)


   // println(questionSetQuestionQuestion(0))


  for(x<-questionSetQuestionQuestion){
questionList=x.getQuestion()
  }

Here I want to add each getQuestion() values to questionList.!

Upvotes: 1

Views: 81

Answers (2)

cmbaxter
cmbaxter

Reputation: 35443

Within the Scala world, mutability should be avoided if possible, so while looping and prepending to a List var will work, there are more palatable options. In your case, I would think of it more as "How can I build a new Collection from an existing one I already have?". Taking that approach you could try:

val newColl = for(x<-questionSetQuestionQuestion)
  yield x.getQuestion()

Or you could just use the map function directly like this:

val newColl = questionSetQuestionQuestion.map(_.getQuestion)

Upvotes: 3

Jatin
Jatin

Reputation: 31724

You need to define it as an empty List and then append to it

var questionList:List[Question]=List[Question]()
questionSetQuestionQuestion=questionSetQuestionService.findQuestionSetQuestionByQuestionSetId(id)

for(x<-questionSetQuestionQuestion){
questionList=x.getQuestion() :: questionList
}

PS: I would recommend lectures by Martin Odersky on Coursera (course: Functional Programming in Scala) where he explains general usage of most of the data structures

Upvotes: 0

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