c# - 如何使用 LINQ 查找特定属性的副本？

Question

Customer customerOne = new Customer("John", "Doe");
Customer customerTwo = new Customer("Super", "Man");
Customer customerThree = new Customer("Crazy", "Guy");
Customer customerFour = new Customer("Jane", "Doe");
Customer customerFive = new Customer("Bat", "Man");

List<Customer> customers = new List<Customer>();
customers.Add(customerOne);
customers.Add(customerTwo);
customers.Add(customerThree);
customers.Add(customerFour);
customers.Add(customerFive);

什么 LINQ 查询会为具有相同姓氏的所有客户返回可枚举值？

结果应包括一个实例:John Doe、Jane Doe、Super Man 和 Bat Man

Answer 1

 customers.GroupBy(c => c.LastName).Where(g => g.Skip(1).Any()).SelectMany(c => c)

或使用 LINQ 语法:

        var q = from c in customers
                group c by c.LastName into g
                where g.Skip(1).Any()
                from c in g
                select c;