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 {
       // ??
  }

并且在输出中我希望有一个Seq of Pots，其中放置了所有可能的鲜花组合。因此，在下面的示例中，输出应为：

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")))
)

任何想法？

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)))

Answer 2

我想通了，现在这个解决方案似乎有效：

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

val pots: Seq[Pot] = res.sliding(flowers.size).map(l => Pot(width, height, l.map(f => FlowerInPot(f._1, f._2, f._3)))).toList

Scala嵌套循环产生

2 个答案: