更改Scala映射中的值

Question

I have a Scala Map like this:

Map("a"->"Null", "b"->"12", "c"->"23", "d"->"", "e"->"apple", "f"->"pear", "g"->"banana", "h"->null) 

Now, I want to replace the values of keys that contains ( a , d , h ) with 0.0, which should result in a map like this:

Map("a"->"0.0", "b"->"12", "c"->"23", "d"->"0.0", "e"->"apple", "f"->"pear", "g"->"banana", "h"->"0.0")

Is there any simple way to do it?

Answer 1

val data = Map("a"->"Null", "b"->"12", "c"->"23", "d"->"", "e"->"apple", "f"->"pear", "g"->"banana", "h"->null)

val replaced = data.map {
  case (k@("a"|"d"|"h"), v) => (k, "0.0")
  case x => x
}

( Edited the above to use Dima's more succinct syntax. )

If your intent is to replace null or null-like values with "0.0", you could do this:

val replaced = data.map {
  case (k, v) if (isNull(v)) => (k, "0.0")
  case x => x
}

I'll leave the implementation of isNull to you.