CODEWITHSUNDEEP
scaladictionarycollections
Some Name
Some Name

Reputation: 9521

What is the easiest way to change key in scala map?

I have a mutable.Map which I need to change a key of if the key is present. If not I want to add a new mapping. Here is what I mean:

val m = mutable.HashMap[String, String]()
val default = "default"
val key = "key_to_change"
val newKey = "key_to_set"
if(m.contains(key)) {
    val oldValue = m(key)
    m remove key
    m += newKey -> oldValue
} else m += newKey -> default

I wonder if scala does not have a more concise way to perform such "key-changing". Can you suggest a better solution?

Upvotes: 1

Views: 4493

Answers (1)

Alexey Romanov
Alexey Romanov

Reputation: 170723

remove "removes a key from this map, returning the value associated previously with that key as an option", so

val value = m.remove(key).getOrElse(default)
m += newKey -> value

Upvotes: 7

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