Pattern matching against Scala Map type
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Tom Morris
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Published on 2012-11-23T22:56:06Z
Indexed on
2012/11/24
11:06 UTC
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Imagine I have a Map[String, String]
in Scala.
I want to match against the full set of key–value pairings in the map.
Something like this ought to be possible
val record = Map("amenity" -> "restaurant", "cuisine" -> "chinese", "name" -> "Golden Palace")
record match {
case Map("amenity" -> "restaurant", "cuisine" -> "chinese") => "a Chinese restaurant"
case Map("amenity" -> "restaurant", "cuisine" -> "italian") => "an Italian restaurant"
case Map("amenity" -> "restaurant") => "some other restaurant"
case _ => "something else entirely"
}
The compiler complains thulsy:
error: value Map is not a case class constructor, nor does it have an unapply/unapplySeq method
What currently is the best way to pattern match for key–value combinations in a Map
?
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