lo/docs/data/it-countby.md

name, slug, sourceRef, category, subCategory, signatures, playUrl, variantHelpers, similarHelpers, position

name	slug	sourceRef	category	subCategory	signatures	playUrl	variantHelpers	similarHelpers	position
CountBy	countby	it/seq.go#L325	it	find	func CountBy[T any](collection iter.Seq[T], predicate func(item T) bool) int		it#find#count	core#slice#countby core#slice#count	35

Counts the number of elements in the collection that satisfy the predicate.

result := it.CountBy(it.Range(1, 11), func(item int) bool {
    return item%2 == 0
})
// 5