Lambda入门示例实例

一些lambda的基础知识,例子都非常的简单.

class Program
    {
        delegate int 乘法(int i);
        static void Main(string[] args)
        {
            //显示数组中大于5的();
            //找出字符串中包含o的字符串();
            //显示年龄大于20岁的人且计数();
            //用枚举器显示年龄大于20岁的();
            //委托乘法();
            //显示字符串以J开头的();
            //整数数组排序();
            //按年龄大小排序();
            //取出姓的唯一值并打印出详细清单();
            


            Console.ReadLine();
        }

        private static void 显示年龄大于20岁的人且计数()
        {
            var names = new[]{
            new {Name="jack",Age=20},
            new {Name="rose",Age=10},
            new {Name="tom",Age=30},
            new {Name="jerry",Age=40},
            new {Name="Black",Age=50},
            };
            var output = names.Where(p => p.Age > 20);
            foreach (var item in output)
            {
                Console.WriteLine("名字是{0},年龄是{1}", item.Name, item.Age);
            }
            Console.WriteLine("年龄大于20岁的一共有:{0}", output.Count());
        }

        private static void 取出姓的唯一值并打印出详细清单()
        {
            var names = new[]{
            new {Name="jack 盖茨",Age=20},
            new {Name="rose 吴",Age=10},
            new {Name="tom 邓",Age=30},
            new {Name="jerry 盖茨",Age=40},
            new {Name="Black 吴",Age=50},
            };
            var output = names.GroupBy(p => p.Name.Split(' ')[1]);
            foreach (var item in output)
            {
                Console.WriteLine(item.Key);
                foreach (var 详细 in item)
                {
                    Console.WriteLine("  " + 详细);
                }
            }
        }

        private static void 按年龄大小排序()
        {
            var names = new[]{
            new {Name="jack",Age=20},
            new {Name="rose",Age=10},
            new {Name="tom",Age=30},
            new {Name="jerry",Age=40},
            new {Name="Black",Age=50},
            };
            var output = names.OrderBy(p => p.Age).Select(p => p);
            foreach (var item in output)
            {
                Console.WriteLine("名字是{0},年龄是{1}", item.Name, item.Age);
            }
        }

        private static void 整数数组排序()
        {
            int[] arr = { 5, 8, 9, 1, 4, 2, 3 };
            var output = arr.OrderBy(p => p);
            foreach (var item in output)
            {
                Console.WriteLine(item);
            }
        }

        private static void 显示字符串以J开头的()
        {
            string[] str = { "tom", "jerry", "jack", "rose" };
            var output = str.Select(p => p).Where(p => p.StartsWith("j"));
            foreach (var item in output)
            {
                Console.WriteLine(item);
            }
        }

        private static void 委托乘法()
        {
            乘法 x2;
            x2 = p => p * 2;
            for (int i = 0; i < 10; i++)
            {

                Console.WriteLine(x2(i));
            }
            x2 = p => p * p;
            for (int i = 0; i < 10; i++)
            {

                Console.WriteLine(x2(i));
            }
        }

        private static void 用枚举器显示年龄大于20岁的()
        {
            var names = new[]{
            new {Name="jack",Age=20},
            new {Name="rose",Age=10},
            new {Name="tom",Age=30},
            new {Name="jerry",Age=40},
            new {Name="Black",Age=50},
            };
            var ie = names.Where(p => p.Age > 20).Select(p => p);
            var output = ie.GetEnumerator();
            while (output.MoveNext())
            {
                Console.WriteLine("名字是{0},年龄是{1}", output.Current.Name, output.Current.Age);
            }
        }

        private static void 找出字符串中包含o的字符串()
        {
            string[] str = { "tom", "jerry", "jack", "rose" };
            var output = str.Select(p => p).Where(p => p.ToCharArray().Contains('o'));
            foreach (var item in output)
            {
                Console.WriteLine(item);
            }
        }

        private static void 显示数组中大于5的()
        {
            int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
            var output = arr.Select(p => p).Where(p => p > 5);
            foreach (var item in output)
            {
                Console.WriteLine(item);
            }
        }
    }