【练习中】求大神指点

[_熱情總會變冷淡]

            List<Student> list = new List<Student>();
            list.Add(new Student { Age = 18, Name = "张三" });
            list.Add(new Student { Age = 17, Name = "李四" });
            list.Add(new Student { Age = 15, Name = "张三" });
            list.Add(new Student { Age = 19, Name = "李四" });
            list.Add(new Student { Age = 20, Name = "张三" });

            int sum = 0;
            foreach (var item in list)
            {
                if (item.Name.Equals("李四"))
                {
                    sum += item.Age;
                }
            }
            
            //现在想用list.ForEach(p => p.Name = "李四")  
            //这种拉姆达表达筛选出 名字为李四的年龄和

[-烟花雨季]

list.Where(p => p.Name == "李四").ToList()

[wuyq11]

int sum=0; list.Where(x=>x.Name.Equals("李四")).ForEach(item => sum+= item.Age);

[xdashewan]

list.Where(p => p.Equals("李四")).Sum(p => p.Age)