Join elem with next one in a functional style

问题

I'm trying to find a way to "join"/"groupby" 2 elements in a list as following :

List("a","b","c","d")  -> List("ab","bc","cd")

With a functional style.

Would someone know how to do this?

Need I use reducer, fold, scan, other higher-order function?

回答1:

Sliding creates subcollections with sliding window, then you just need to map this sublists to strings:

List("a","b","c","d").sliding(2,1).map{case List(a,b) => a+b}

回答2:

Try

val xs = List("a","b","c","d")
(xs, xs.tail).zipped.map(_ ++ _) // List(ab, bc, cd)

回答3:

You can use sliding to create a window:

val l = List("a","b","c","d")
val res = l.sliding(2).map(_.reduce(_ + _))
res.foreach(println)

this results with

ab
bc
cd

来源：https://stackoverflow.com/questions/55751657/join-elem-with-next-one-in-a-functional-style