c# lambda表达式

// Lambda表达式的基本形式是：(参数列表) => 表达式或语句块

// 示例1：简单的Lambda表达式，没有参数，返回一个字符串
Func<string> getHello = () => "Hello, World!";
Console.WriteLine(getHello()); // 输出: Hello, World!

// 示例2：带有一个参数的Lambda表达式
Func<int, int> doubleNumber = x => x * 2;
Console.WriteLine(doubleNumber(5)); // 输出: 10

// 示例3：带有多个参数的Lambda表达式
Func<int, int, int> addNumbers = (a, b) => a + b;
Console.WriteLine(addNumbers(3, 7)); // 输出: 10

// 示例4：Lambda表达式中使用语句块
Func<int, int> squareAndAddTen = num => {
    int squared = num * num;
    return squared + 10;
};
Console.WriteLine(squareAndAddTen(4)); // 输出: 26

// 示例5：Lambda表达式用于LINQ查询
List<int> numbers = new List<int> { 1, 2, 3, 4, 5 };
var evenNumbers = numbers.Where(n => n % 2 == 0);
foreach (var num in evenNumbers)
{
    Console.WriteLine(num); // 输出: 2, 4
}