Newbie question, how do you optimize/reduce expressions like these:
when(x1._1,x1._2).when(x2._1,x2._2).when(x3._1,x3._2).when(x4._1,x4._2).when(x5._1,x5._2)....
.when(xX._1,xX._2).otherwise(z)
The x1, x2, x3, xX are maps where x1._1 is the condition and x._2 is the "then".
I was trying to save the maps in a list and then use a map-reduce but it was producing a:
when(x1._1,x1._2).otherwise(z) && when(x2._1,x2._2).otherwise(z)...
Which is wrong. I have like 10 lines of pure when case and would like to reduce that so my code is more clear.
You can use foldLeft on the maplist:
val maplist = List(x1, x2) // add more x if needed
val new_col = maplist.tail.foldLeft(when(maplist.head._1, maplist.head._2))((x,y) => x.when(y._1, y._2)).otherwise(z)
An alternative is to use coalesce. If the condition is not met, null is returned by the when statement, and the next when statement will be evaluated until a non-null result is obtained.
val new_col = coalesce((maplist.map(x => when(x._1, x._2)) :+ z):_*)