Lambda 遍历

Posted 2020-08-24 海阔天空XM

遍历列表元素

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ForEachDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(LambdaAndEach()); //输出：‘1‘,‘4‘,‘5‘,‘6‘,‘7‘,‘8‘,‘9‘,‘10‘
            Console.ReadKey();

        }

        public static string LambdaAndEach()
        {
            //数据源
            var retList = new List<int>() { 1, 4, 5, 6, 7, 8, 9, 10 };

            var sbBuilder = new StringBuilder();

            retList.ForEach(item =>
            {
                //如果是最后一个元素则用(‘item‘)包裹，否则用(‘item‘,)包裹元素
                if (item == retList[retList.Count - 1])
                {
                    sbBuilder.Append("‘" + item + "‘");
                }
                else
                {
                    sbBuilder.Append("‘" + item + "‘,");
                }
            });

            return sbBuilder.ToString();
        }

    }
}

例二：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class User
    {
        public Guid Id { get; set; }
        public string UserName { get; set; }
        public string Pwd { get; set; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            //数据源
            var dataSource = new List<User>()
            {
                new User() {Id = Guid.NewGuid(), UserName = "admin", Pwd = "123"},
                new User() {Id = Guid.NewGuid(), UserName = "zhang", Pwd = "345"},
                new User() {Id = Guid.NewGuid(), UserName = "liu", Pwd = "999"}
            };

            var uids = dataSource.Select(u => u.Id.ToString());

            Console.WriteLine("所有用户ID,用空格|隔开\n{0}", string.Join(" | ", uids));
            //输出：所有用户ID,用空格|隔开
            //44927238 - 8ce7 - 4581 - 91ec - 4797712dc85a | 116037c7 - 4275 - 4491 - 9a2a - afb887ea2cf0 | 2c157abc - 8f13 - 4394 - b5e3 - 4778a9a420df
            Console.ReadKey();

        }
    }
}