C#怎么用一行代码把一个集合的属性值根据条件改了,而其他值不变
刚无聊看到群里一位朋友在提问,大晚上没人解答,遂自己默默打开了VS,敲起了代码。
问题:请问怎么将集合newFoods中Name含有"包子"的Number+1,可以一句话写出来 ?
List<Food> newFoods = new List<Food>{ new Food { Money = 10, Name = "天津包子", Number=1 }, new Food { Money = 10, Name = "狗不理包子", Number = 1 }, new Food { Money = 10, Name = "小笼包子", Number = 1 }, new Food { Money = 10, Name = "馒头", Number = 1 }, new Food { Money = 10, Name = "粽子", Number = 1 } };
方法有很多种,但是每种的效率是不一样的
其中select会把数据源投射到新表中,所以会慢点
1楼给出的代码更加简洁快速
最后的代码:
1 #region 2 public class Food 3 { 4 public string Name { get; set; } 5 public int Money { get; set; } 6 public int Number { get; set; } 7 } 8 static void Example1() 9 { 10 List<Food> newFoods = new List<Food>{ 11 new Food { Money = 10, Name = "天津包子", Number=1 }, 12 new Food { Money = 10, Name = "狗不理包子", Number = 1 }, 13 new Food { Money = 10, Name = "小笼包子", Number = 1 }, 14 new Food { Money = 10, Name = "馒头", Number = 1 }, 15 new Food { Money = 10, Name = "粽子", Number = 1 } 16 }; 17 //lambda写法1 18 newFoods.ForEach(o => 19 { 20 o.Number = o.Name.Contains("包子") ? o.Number + 1 : o.Number; 21 }); 22 //lambda写法2 23 newFoods = newFoods.Select(o => 24 { 25 o.Number = o.Name.Contains("包子") ? o.Number + 1 : o.Number; 26 return o; 27 }).ToList(); 28 //普通写法 29 for (int i = 0; i < newFoods.Count; i++) 30 { 31 newFoods[i].Number = newFoods[i].Name.Contains("包子") ? newFoods[i].Number + 1 : newFoods[i].Number; 32 } 33 //遍历输出 34 foreach (Food food in newFoods) 35 { 36 Console.WriteLine("名称:" + food.Name + ",价格:" + food.Money + ",数量:" + food.Number); 37 } 38 Console.ReadLine(); 39 } 40 #endregion