工作总结 EF GroupBy() Select() Select() 中 Count() 分组 求总

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> strarr = new List<string>()
            {
                "a","a","b","b","c"
            };
            var ss = strarr.FirstOrDefault(a => a == "z");
            var s = strarr.GroupBy(a => a).Select(a => new { countsss = a.Count() }).ToList();   //分组 求总
            var s3 = strarr.Select(a => new { countsss = a.Count() }).ToList();   //  不分组  就是  当前元素 (a取得就是当前元素) 求总   countsss 全是 1
            Console.WriteLine();
            Console.WriteLine();

        }
    }
}

 

 

 

 

 

 

posted @ 2018-05-04 10:35  ~雨落忧伤~  阅读(3342)  评论(0)    收藏  举报