Dear all, Another one was: Set>>collectAll: aBlock | newSet | newSet := Set new: self size. array do: [:each | each ifNotNil: [newSet addAll: (aBlock value: each)]]. ^ newSet In analogy with addAll: aCollection. If useful, maybe we should provide a more general implementation for Collection instead of only Set I needed so far. Kind Regards, Bart -- imagination is more important than knowledge - Albert Einstein Logic will get you from A to B. Imagination will take you everywhere - Albert Einstein Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning. - Albert Einstein The true sign of intelligence is not knowledge but imagination. - Albert Einstein Gravitation is not responsible for people falling in love. - Albert Einstein