如何在 C# 中查找一个列表中不在另一个列表中的项目?
csharpserver side programmingprogramming更新于 2025/5/4 17:22:17
LINQ Except 运算符属于 LINQ 中的 Set 运算符类别
Except() 方法需要两个集合并查找第二个集合中不存在的元素
除扩展外，该方法不会为复杂类型的集合返回正确的结果。
使用 Except() 方法的示例
using System;
using System.Collections.Generic;
using System.Linq;
namespace DemoApplication {
class Program {
static void Main(string[] args) {
List<string> animalsList1 = new List<string> {
"tiger", "lion", "dog"
};
Console.WriteLine($"Values in List1:");
foreach (var val in animalsList1) {
Console.WriteLine($"{val}");
}
List<string> animalsList2 = new List<string> {
"tiger", "cat", "deer"
};
Console.WriteLine($"Values in List2:");
foreach (var val in animalsList2) {
Console.WriteLine($"{val}");
}
var animalsList3 = animalsList1.Except(animalsList2);
Console.WriteLine($"Value in List1 that are not in List2:");
foreach (var val in animalsList3) {
Console.WriteLine($"{val}");
}
Console.ReadLine();
}
}
}
输出
上述代码的输出是
Values in List1: tiger lion dog Values in List2: tiger cat deer Value in List1 that are not in List2: lion dog
使用 Where 子句的示例
using System;
using System.Collections.Generic;
using System.Linq;
namespace DemoApplication {
class Program {
static void Main(string[] args) {
List<Fruit> fruitsList1 = new List<Fruit> {
new Fruit {
Name = "Apple",
Size = "Small"
},
new Fruit {
Name = "Orange",
Size = "Small"
}
};
Console.WriteLine($"Values in List1:");
foreach (var val in fruitsList1) {
Console.WriteLine($"{val.Name}");
}
List<Fruit> fruitsList2 = new List<Fruit> {
new Fruit {
Name = "Apple",
Size = "Small"
},
new Fruit {
Name = "Mango",
Size = "Small"
}
};
Console.WriteLine($"Values in List2:");
foreach (var val in fruitsList2) {
Console.WriteLine($"{val.Name}");
}
var fruitsList3 = fruitsList1.Where(f1 => fruitsList2.All(f2 => f2.Name != f1.Name));
Console.WriteLine($"Values in List1 that are not in List2:");
foreach (var val in fruitsList3) {
Console.WriteLine($"{val.Name}");
}
Console.ReadLine();
}
}
public class Fruit {
public string Name { get; set; }
public string Size { get; set; }
}
}
输出
上述代码的输出是
Values in List1: Apple Orange Values in List2: Apple Mango Values in List1 that are not in List2: Orange
