Select first 'N' elements from map in Scala

Question

Is there an elegant method of extracting first 'N' elements from a Map ?

I could create a new Map and iterate over the values that are to be selected, is there a function that accomplishes this ?

Answer 1

From the docs for the take method on Map:

Selects first n elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

In the case of maps the collection isn't ordered, so don't count on getting the first n elements—in fact the concept of the first n elements doesn't even exist for maps.

But take will give you some first n elements, and it sounds like this is what you want:

scala> Map('a -> 1, 'b -> 2, 'c -> 3).take(2)
res1: scala.collection.immutable.Map[Symbol,Int] = Map('a -> 1, 'b -> 2)

In this case you happen to get the two elements that came first in the definition, but don't count on this happening.