如何在scala中的列表列表上执行转置? [英] How to perform transpose on List of Lists in scala?

问题描述

我有一个具有以下结构的 scala列表:

I have a scala list of following structure:

val list = List(
  List(a1,a2,a3,a4,a5),
  List(b1,b2,b3,b4,b5),
  List(c1,c2,c3,c4,c5)
)

从此列表中，我想生成一个看起来像这样的列表:

From this list, I want to generate a list which would look like:

List(
  List(a1,b1,c1),
  List(a2,b2,c2),
  List(a3,b3,c3),
  List(a4,b4,c4),
  List(a5,b5,c5)
)

我如何在Scala中实现这一目标?

How do I achieve this in scala ?

推荐答案

如果您有固定数量的此类列表，则可以使用zipped将它们压缩在一起(成为元组).如您的示例:

If you have a fixed number of such lists, you can use zipped to zip them together (into tuples). As in your example:

scala> (List(a1,a2,a3,a4), List(b1,b2,b3,b4), List(c1,c2,c3,c4)).zipped.toList
List((a1,b1,c1),(a2,b2,c2),(a3,b3,c3),(a4,b4,c4))

如果您真的想要拥有以上功能的全部功能，那么它只是列表列表的transpose:

If you really want the full power of what you have above, it is just the transpose of your list of lists:

scala> List(List(a1,a2,a3,a4), List(b1,b2,b3,b4), List(c1,c2,c3,c4)).transpose
List(List(a1,b1,c1),List(a2,b2,c2),List(a3,b3,c3),List(a4,b4,c4))

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