C#linq計算總條數並去重複的寫法

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一，在實際需求中我們會存在選出了一個集合，而這時我們需要通過集合的某幾個欄位來計算重複，和統計重複的數量，這時我們可以用到linq來篩選和去重複。

二，如下代碼：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Bao{    class Program    {        static void Main(string[] args)        {            List<Demo> result = new List<Demo>();            result.Add(new Demo()            {                Name = "1",                Pro = "1",                Code = "1"            });            result.Add(new Demo()            {                Name = "1",                Pro = "1",                Code = "1"            });            result.Add(new Demo()            {                Name = "2",                Pro = "2",                Code = "3"            });            result.Add(new Demo()            {                Name = "3",                Pro = "3",                Code = "3"            });            result.Add(new Demo()            {                Name = "4",                Pro = "4",                Code = "4"            });            var test = from a in result                       select new                       {                           SchoolName = a.Name,                           Province = a.Pro,                           SchoolCode = a.Code,                           counts = (from t in result                                     where t.Name == a.Name && t.Pro == a.Pro && t.Code == a.Code                                     group t by new { Name = t.Name, Pro = t.Pro, Code = t.Code } into g                                     select new { counts = g.Count() }                                     ).FirstOrDefault().counts                       };            var ttt = test.ToList();            var aaa = ttt.Distinct().ToList();        }    }    public class Demo    {        public string Code { get; set; }        public string Name { get; set; }        public string Pro { get; set; }        public int counts { get; set; }    }}

 

C#linq計算總條數並去重複的寫法