LINQ 基本子句之三 let

let子句，可以作为临时变量储存表达式的结果，但是let子句一旦初始化后无法再次进行更改。

1.

        static void Main(string[] args)
        {   string[] names = { "xyz", "now you see", "i can say", "my abc" };
            IEnumerable<string> queryFirstNames =
                from name in names
                let firstName = name.ToUpper()
                select firstName;

            foreach (string s in queryFirstNames)
            Console.Write(s + " ");
            Console.ReadLine();
        }

2.

           static void Main(string[] args)
         {
            string[] names = { "a 12", "b 13", "i 14", "m 15" };
            var Names =
                from name in names
                let firstName = name.Split(' ')
                from Upper in firstName
                let U = Upper.ToString().ToUpper()
                select U;

            foreach (string s in Names)
            Console.Write(s + " ");
            Console.ReadLine();
        }

运行结果

至此，基本语句结束。