Scala 嵌套循环产量

Question

我想知道在 scala 中是否有一种简单的方法可以做这样的事情:

case class Pot(width: Int, height: Int, flowers: Seq[FlowerInPot])
case class FlowerInPot(x: Int, y: Int, flower: String)

val flowers = Seq("tulip", "rose")
val height = 3
val width = 3

val res =
  for (flower <- flowers;
       h <- 0 to height;
       w <- 0 to width) yield {
       // ??
  }

在输出中，我想要一个 Seq of Pots，其中放置了所有可能的花组合。所以在下面的例子中，输出应该是:

Seq(
  Pot(3, 3, Seq(FlowerInPot(0, 0, "tulip"), FlowerInPot(0, 1, "rose"))),
  Pot(3, 3, Seq(FlowerInPot(0, 0, "tulip"), FlowerInPot(0, 2, "rose"))),
  Pot(3, 3, Seq(FlowerInPot(0, 0, "tulip"), FlowerInPot(1, 0, "rose"))),
  Pot(3, 3, Seq(FlowerInPot(0, 0, "tulip"), FlowerInPot(1, 1, "rose"))),
  ...
  Pot(3, 3, Seq(FlowerInPot(2, 2, "tulip"), FlowerInPot(2, 1, "rose")))
)

有什么想法吗？

Answer 1

这是你想要的吗？

case class FlowerInPot(x: Int, y: Int, flower: String)
case class Pot(width: Int, height: Int, flowers: Seq[FlowerInPot])

val x, y = 0
val flowers = Seq("tulip", "rose")
val height = 3
val width = 3

val res = for {
  h <- 0 to height
  w <- 0 to width
} yield Pot(height, width, flowers.map(flower => FlowerInPot(w, h, flower)))