How do I return a sequence in Swift?

Question

I\'m trying to write an extension for the Matrix example from the book, slightly tweaked to be generic.
I\'m trying to write a method called getRow

Answer 1

I think you are being mislead by the Swift compiler (which is a bit flaky at the moment). The type for your range 0..self.columns is Range, which is not a Sequence or Collection, so I don't think it can be used via map.

The implementation works for me:

extension Matrix {
  func getRow(index: Int) -> T[] {
    var row = T[]()
    for col in 0..self.columns {
      row.append(self[index, col])
    }
    return row
  }
}