List對象集合一些擴展方法 本文轉載自 查看原文 2017-04-13 17:50 5123 C#開發中的方法總結/ list擴展方法/ list/ 遍歷集合 // 商品集合信息 List<Product> list = new List<Product>() { new Product() {Id = 1,Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 2,Name = "IPhone4s",Price = 2999,Remark = "心動不如行動"}, new Product() {Id = 3,Name = "IPhone5",Price = 3999,Remark = "心動不如行動"}, new Product() {Id = 4,Name = "IPhone5s",Price = 4999,Remark = "心動不如行動"}, new Product() {Id = 5,Name = "IPhone6",Price = 5999,Remark = "心動不如行動"}, new Product() {Id = 6,Name = "IPhone6s",Price = 6999,Remark = "心動不如行動"}, new Product() {Id = 7,Name = "IPhone7",Price = 7999,Remark = "心動不如行動"}, new Product() {Id =8,Name = "IPhone7s",Price = 8999,Remark = "心動不如行動"}, new Product() {Id = 9,Name = "IPhone7s Plus",Price = 9999,Remark = "心動不如行動"}, // 除了ID其它字段重復數據 new Product() {Id = 1,Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 10,Name = "IPhone4s",Price = 2999,Remark = "心動不如行動"}, new Product() {Id = 11,Name = "IPhone5",Price = 3999,Remark = "心動不如行動"}, new Product() {Id = 12,Name = "IPhone5s",Price =4999,Remark = "心動不如行動"}, new Product() {Id = 13,Name = "IPhone6",Price = 5999,Remark = "心動不如行動"}, new Product() {Id = 14,Name = "IPhone6s",Price = 6999,Remark = "心動不如行動"}, // 完全重復數據 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"}, }; //// 1：根據條件篩選價格大於3000的商品信息 //var query = list.Where(p=>p.Price>3000).ToList(); //foreach (var item in query) //{ // Console.WriteLine(item.Id+"--"+item.Code + "--" +item.Name + "--" +item.Price + "--" +item.Remark); //} //// 2-1：去除重復的數據(聲明一個類繼承：IEqualityComparer<Product>) //var query = list.Distinct(new DistinctComparer()); //foreach (var item in query.ToList()) //{ // Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark); //} //// 2-2：利用HashSet去除重復數據 //var js = new List<string>() { "1", "1", "2", "3" }; //HashSet<string> hs = new HashSet<string>(js); //此時已經去掉重復的數據保存在hashset中 //foreach (var item in hs) //{ // Console.WriteLine(item); //} //// 獲取list集合總數 //var query = list.Count(); //Console.WriteLine(query); //// 新增數據 //list.Add(new Product() { Id = 10, Price = 123, Remark = "新增", Name = "IPhone8" }); //foreach (var item in list) //{ // Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark); //} //// 新增數據 //list.AddRange(new List<Product>() {new Product() {Id = 20,Name = "AddRange方法",Price = 1111,Remark = "AddRange添加"} }); //foreach (var item in list) //{ // Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark); //} //// 刪除所有數據 //list.Clear(); //var query = list.Count(); //Console.WriteLine(query); //// 刪除指定數據 //list.Remove(new Product() { Id = 14, Name = "IPhone6s", Price = 6999, Remark = "心動不如行動" }); //foreach (var item in list) //{ // Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark); //} // ForEach 遍歷集合 list.ForEach(p => { Console.WriteLine(p.Id + "--" + p.Code + "--" + p.Name + "--" + p.Price + "--" + p.Remark); }); list集合中還有許多擴展方法。以后持續補充。 × 免責聲明！ 本站轉載的文章為個人學習借鑒使用，本站對版權不負任何法律責任。如果侵犯了您的隱私權益，請聯系本站郵箱[e-mail]刪除。 猜您在找 針對list中的對象數據的一些簡單處理 Java中一些集合的用法（List、Map、List） js里面Object的一些方法 JS中Object的一些關於原型的方法 關於Function原型對象和Object原型對象的一些疑惑 擴展原生js的一些方法 [ES6] 一些類型方法的擴展 集合(set)的一些常用方法 List集合去重的一些方法（常規遍歷、Set去重、java8 stream去重、重寫equals和hashCode方法） List集合去重的一些方法（常規遍歷、Set去重、java8 stream去重、重寫equals和hashCode方法） 粵ICP備18138465號 © 2018-2025 CODEPRJ.COM

 // 商品集合信息
            List<Product> list = new List<Product>()
            {
                new Product() {Id = 1,Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                new Product() {Id = 2,Name = "IPhone4s",Price = 2999,Remark = "心動不如行動"},
                new Product() {Id = 3,Name = "IPhone5",Price = 3999,Remark = "心動不如行動"},
                new Product() {Id = 4,Name = "IPhone5s",Price = 4999,Remark = "心動不如行動"},
                new Product() {Id = 5,Name = "IPhone6",Price = 5999,Remark = "心動不如行動"},
                new Product() {Id = 6,Name = "IPhone6s",Price = 6999,Remark = "心動不如行動"},
                new Product() {Id = 7,Name = "IPhone7",Price = 7999,Remark = "心動不如行動"},
                new Product() {Id =8,Name = "IPhone7s",Price = 8999,Remark = "心動不如行動"},
                new Product() {Id = 9,Name = "IPhone7s Plus",Price = 9999,Remark = "心動不如行動"},

                // 除了ID其它字段重復數據
                new Product() {Id = 1,Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                new Product() {Id = 10,Name = "IPhone4s",Price = 2999,Remark = "心動不如行動"},
                new Product() {Id = 11,Name = "IPhone5",Price = 3999,Remark = "心動不如行動"},
                new Product() {Id = 12,Name = "IPhone5s",Price =4999,Remark = "心動不如行動"},
                new Product() {Id = 13,Name = "IPhone6",Price = 5999,Remark = "心動不如行動"},
                new Product() {Id = 14,Name = "IPhone6s",Price = 6999,Remark = "心動不如行動"},

                // 完全重復數據
                 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
                 new Product() {Id = 1,Code = "123456789",Name = "IPhone4",Price = 1999,Remark = "心動不如行動"},
            };

            //// 1：根據條件篩選價格大於3000的商品信息
            //var query = list.Where(p=>p.Price>3000).ToList();
            //foreach (var item in query)
            //{
            //    Console.WriteLine(item.Id+"--"+item.Code + "--" +item.Name + "--" +item.Price + "--" +item.Remark);
            //}

            //// 2-1：去除重復的數據(聲明一個類繼承：IEqualityComparer<Product>)
            //var query = list.Distinct(new DistinctComparer());
            //foreach (var item in query.ToList())
            //{
            //    Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark);
            //}

            //// 2-2：利用HashSet去除重復數據
            //var js = new List<string>() { "1", "1", "2", "3" };
            //HashSet<string> hs = new HashSet<string>(js); //此時已經去掉重復的數據保存在hashset中

            //foreach (var item in hs)
            //{
            //    Console.WriteLine(item);
            //}

            //// 獲取list集合總數
            //var query = list.Count();
            //Console.WriteLine(query);
            
            //// 新增數據
            //list.Add(new Product() { Id = 10, Price = 123, Remark = "新增", Name = "IPhone8" });
            //foreach (var item in list)
            //{
            //    Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark);
            //}

            //// 新增數據
            //list.AddRange(new List<Product>() {new Product() {Id = 20,Name = "AddRange方法",Price = 1111,Remark = "AddRange添加"} });
            //foreach (var item in list)
            //{
            //    Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark);
            //}

            //// 刪除所有數據
            //list.Clear();
            //var query = list.Count();
            //Console.WriteLine(query);

            //// 刪除指定數據
            //list.Remove(new Product() { Id = 14, Name = "IPhone6s", Price = 6999, Remark = "心動不如行動" });
            //foreach (var item in list)
            //{
            //    Console.WriteLine(item.Id + "--" + item.Code + "--" + item.Name + "--" + item.Price + "--" + item.Remark);
            //}

            // ForEach 遍歷集合
            list.ForEach(p =>
            {
                Console.WriteLine(p.Id + "--" + p.Code + "--" + p.Name + "--" + p.Price + "--" + p.Remark);

            });

 

list集合中還有許多擴展方法。以后持續補充。