From: Erwin Date: 2008-08-15T02:22:18+09:00 Subject: nested loop I know there is DRY way tow rite that, but I don't remember how residence_rentals_ids = [] residences = user.franchise.residences for residence in residences residence_rentals_ids = residence.rentals.map {|rental| rental[:id] }.compact end I tried unsuccessfully : residence_rentals_ids = user.franchise.residences.each { |residence| residence.rentals.map { |rental| rental[:id}.compact } thanks for your lights erwin