Question

how can I remove this yield’s? I wanna use a map instead of:

val cols = for(x <- 0 to 6) yield for(y <- 0 to 5) yield apply(x, y)

Is this possible?

Thanks!

Best regards,
John

Answer 1

That would be pretty simple:

val cols = (0 to 6).map(x => (0 to 5).map( y => apply(x,y)))

UPD

There may be variations in maps. If you want flat object without nested structure it is better to use flatMap instead of just map:

def apply(x: Int, y: Int) = (x,y)
scala> val cols = (0 to 6).map(x => (0 to 5).map( y => apply(x,y)))
//cols: scala.collection.immutable.IndexedSeq[scala.collection.immutable.IndexedSeq[(Int, Int)]] =  ...

scala> val cols = (0 to 6).flatMap(x => (0 to 5).map( y => apply(x,y)))
//cols: scala.collection.immutable.IndexedSeq[(Int, Int)] = ...

or just flatten result at the end:

scala> val cols = (0 to 6).map(x => (0 to 5).map( y => apply(x,y))).flatten
//cols: scala.collection.immutable.IndexedSeq[(Int, Int)] = ...