Scala将元素追加到索引序列

Question

I have a indexed sequence of 10 doubles and I want to append few more doubles to the original indexed sequence. I tried using :: and ++ but it doesn't work. I can only use val.

val features = functionCount.map(_.toDouble).toIndexedSeq //original indexed sequence
features +=  avgLength //tried :: also

How do I append more doubles to this sequence, I need a IndexedSeq in the end.

Answer 1

You can't change features , unless it's mutable. Given the comment that "you can only use val", this sounds like homework, and, if it is, I doubt you can use mutable sequences either. In that case, you have to abandon that approach and tackle the problem at a much higher level, with either recursion or folding.