I have a collections groupBy / filter / map / redu...

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[v79]

I have a collections groupBy / filter / map / reduce challenge I can't quite get right. Can anyone help? I think I might be trying to do to much in a single line of code:
given:

allTags [
			tag { category: "genre", value: "classical", count=0, multiple=false },
			tag { category: "genre", value: "jazz",, count=0, multiple=false },
			tag { category: "composer", value: "mahler", count=0, multiple=false },
			tag { category: "composer", value: "bach", count=0, multiple=false },
			tag { category: "genre", value: "classical", count=0, multiple=false },
			tag { category: "composer", value: "bach", count=0, multiple=false },
	]

I want:

groupedList [
			tag { category: "genre", value: "classical", count=2, multiple=true },
			tag { category: "genre", value: "jazz", count=1, multiple=false },
			tag { category: "composer", value: "mahler", count=1, multiple=false }
			tag { category: "composer", value: "bach", count=2, multiple=true }
	]
// TODO: this isn't counting correctly
val groupedList = allTags.groupBy { it.label }.values.map { it.reduce { acc, item -> Tag(category = item.category, label = item.label, url =  item.url, postCount = item.postCount++, hasPosts = item.postCount > 1) } }

[spand]

There is no label in your objects

[spand]

But it seems you need to group by category, value then map each list to the wanted value (seems simpler than using reduce)

[v79]

Sorry, label=value. I keep changing the model.