Created
September 3, 2014 01:38
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toMultiMap
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implicit class scEnrichColl[Coll <: Traversable[(_,_)]](val __this: Coll) extends AnyVal { | |
def toMultiMap[Result, A, B](implicit view: Coll <:< Traversable[(A, B)], cbf: CanBuildFrom[Coll, B, Result]): Map[A, Result] = { | |
var result = collection.mutable.Map[A, mutable.Builder[B, Result]]() | |
result = result.withDefault { a => val r = cbf(__this); result.update(a, r); r} | |
for((a,b) <- view(__this)) { | |
result(a) += b | |
} | |
result.mapValues(_.result()).toMap | |
} | |
} |
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