Convert IndexedSeq to Array-CodePudding

I have a 2D Array, say a 3x3 Matrix, and want to multiply all elements with a given value. This is what I have so far:

val m = Array(
  Array(1,2,3),
  Array(4,5,6),
  Array(7,8,9)
)

val value = 3

for ( i <- m.indices) yield m(i).map(x => x*value)

//Result:
//IndexedSeq[Array[Int]] = Vector(Array(3, 6, 9), Array(12, 15, 18), Array(21, 24, 27))

Problem is I have an IndexedSeq[Array[Int]] now but I need this to be an Array[Array[Int]] just like val m.

I know that for example for (i <- Array(1, 2, 3)) yield i results in an Array[Int] but I can't figure out how to put this all together.

Just appending .toArray doesn't work also

CodePudding user response：

If you want to create new Array instances (copy):

  val m = Array(
    Array(1,2,3),
    Array(4,5,6),
    Array(7,8,9)
  )
  val value = 3
  val newM = m.map{ array => array.map{x => x * value}}

Or, if you want to modify the original arrays "in-place":

  val m = Array(
    Array(1,2,3),
    Array(4,5,6),
    Array(7,8,9)
  )
  val value = 3  
  for (arr <- m; j <- arr.indices) {
    arr(j) *= value
  }