在Scala中创建并填充二维数组

What's the recommended way of creating a pre-populated two-dimensional array in Scala? I've got the following code:

在Scala中创建预先填充的二维数组的推荐方法是什么？我有以下代码：

val map = for {
    x <- (1 to size).toList
} yield for {
        y <- (1 to size).toList
    } yield (x, y)

How do I make an array instead of list? Replacing .toList with .toArray doesn't compile. And is there a more concise or readable way of doing this than the nested for expressions?

如何制作数组而不是列表？用.toArray替换.toList不会编译。还有比嵌套表达式更简洁或可读的方法吗？

2 个解决方案

#1

On Scala 2.7, use Array.range:

在Scala 2.7上，使用Array.range：

for {
  x <- Array.range(1, 3)
} yield for {
  y <- Array.range(1, 3)
} yield (x, y)

On Scala 2.8, use Array.tabulate:

在Scala 2.8上，使用Array.tabulate：

Array.tabulate(3,3)((x, y) => (x, y))

#2

Among other ways, you can use use Array.range and map:

除了其他方法，您可以使用使用Array.range和map：

scala> Array.range(0,3).map(i => Array.range(0,3).map(j => (i,j)))
res0: Array[Array[(Int, Int)]] = Array(Array((0,0), (0,1), (0,2)), Array((1,0), (1,1), (1,2)), Array((2,0), (2,1), (2,2)))

Or you can use Array.fromFunction:

或者您可以使用Array.fromFunction：

scala> Array.fromFunction((i,j) => (i,j))(3,3)                    
res1: Array[Array[(Int, Int)]] = Array(Array((0,0), (0,1), (0,2)), Array((1,0), (1,1), (1,2)), Array((2,0), (2,1), (2,2)))

Scala 2.8 gives you even more options--look through the Array object. (Actually, that's good advice for 2.7, also....)

Scala 2.8为您提供了更多选项 - 查看Array对象。（实际上，这对2.7的好建议也是......）

#1