Get versus direct access on Maps in Scala
I know I haven’t posted in a while, I’m going to try to post more often. I’ll make a relevant post soon about what I’ve been up to. For now, I want to talk about Scala.
I’ve been learning Scala, it’s a great little programming language. I would like to see java replaced by it eventually.
I was dealing with a very specific issue in scala, whereby I was matching a Map and getting the following error:
error: constructor cannot be instantiated to expected type;
[scalac] found : Some[A]
[scalac] required: Int
[scalac] case Some(x) => {
It turns out, there are two ways to access a Map. So if I have
val wallet = Map(”Money” -> 100)
wallet(”Money”) returns 100
wallet(”Monkey”) throws an exception
wallet.get(”Money”) returns Some(100)
wallet.get(”Monkey”) returns None
Therefore, I was supposed to be using get when matching access to wallet:
val numOfM= wallet.get(”Monkey”)
numOfM match {
Some(num) => {println “#:” + num}
None => {println “You don’t have enough bananas :(”}
}