If An airline is "countable", this means that there MUST be a flight attendant present on the plane, whose sole job is to count: So when you have to simply iterate through the in-memory collection, use IEnumerable, if you need to do any manipulation with the collection like Dataset and https://mylesrbgmr.affiliatblogger.com/80294157/greatest-kılavuzu-c-ienumerable-nerelerde-kullanılıyor-için