In Swift: (0...100) .filter { $0 % 2 == 0 } .map { $0 * 2 } Will pass through the sequence multiple times, yes. But to avoid it it's as eas

In Swift: (0...100) .filter { $0 % 2 == 0 } .map { $0 * 2 } Will pass through the sequence multiple times, yes. But to avoid it it's as easy as: (0...100) .lazy .filter { $0 % 2 == 0 } .map { $0 * 2 }