发送函数以在Scala中折叠

Question

How do I send an accumulation function to fold in Scala, the below example will say (Int,Int,Int) does not take parameters .

My questions are:

• Why do I get this error?

• How is the idomatic way to do what I want in the code below?

   def a(xs: List[(Int,Int)]): Int = { def logic(acc: (Int,Int, Int), post: (Int,Int)): (Int,Int,Int) = { // do some logic (1, 2, 3) } val to = xs foldLeft((0,0,0))(logic _) to._3 } 

Answer 1

The problem is here:

xs foldLeft((0,0,0))(logic _)

Never go for the dotless notation unless it's for an operator. This way it works.

xs.foldLeft((0,0,0))(logic _)

Without a context I believe this is idiomatic enough.

Answer 2

我没有您代码的目标，但您可以通过以下方式解决您描述的问题：

val to = xs.foldLeft((0,0,0))(logic)

Answer 3

尝试这个

xs.foldLeft((0,0,0), logic)

Answer 4

foldLeft is a curried function so it requires a . - go for xs.foldLeft and it will work.