functional programming - Scala combine Seq of Timestamps -

hello i'm learning scala , have seq of object of following case class:

case class historycounter(time: datetime, counter:int)

now combine value of counter based on timestamp time. sum of counters time on same day or same week.

how can this? 1 of collection functions fold or map capable of doing this?

if had list of these case classes called list, 1 way so:

  val counts =      list.groupby(_.time).map{       case (k, v) => (k, v.map(_.counter).sum)     }

or more succinctly:

list.groupby(_.time).mapvalues(_.map(_.counter).sum)

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