I want to use tuple returned from a method to make a new hashmap item but it gives me error when I write like this
var data= HashMap[String,String]()
data.update(choose("name"))
def choose(a:String):(String,String)= return (a, "Pete")
How do you use tuple to update the hashmap?
Eclipse IDE tells me "not enough arguments for method update: (key: String, value: String)Unit. Unspecified value parameter value." and won't let me compile the script.
Instead of
// update requires a separate parameters for key and value
data.update(choose("name")) // won't compile !
// the following will work
val (key,value) = choose("name")
data.update (key,value)
Use
data+=choose("name") // += takes (key,value) tuple as a parameter
This works as well:
(data.update _).tupled(choose("name"))
tupled converts a function requiring multiple arguments into a function requiring a tuple of arguments.
In your case, it's not a clean as Vlad's approach, but, in general, tupled can be used when you have a tuple containing your arguments.
val f = (a: String, b: String, c: String) => a + b + c
val myargs = ("1", "2", "3")
println(f.tupled(myargs)) // produces "123"
data.update()does not accept a tuple.