Swift 2.2 (3.0) 中映射修改对象数组

在 Swift 2.2 (3.0) 中，我们可以使用映射（Map）的特性来修改对象数组。映射是一种高阶函数，它可以将一个数组中的每个元素都应用一个特定的转换方法，并返回一个新的数组。

swift
class Person {
    var name: String
    var age: Int
    
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
}

swift
let people = [Person(name: "Alice", age: 25), Person(name: "Bob", age: 30), Person(name: "Charlie", age: 35)]
let uppercasedNames = people.map { $0.name.uppercased() }
print(uppercasedNames) // 输出 ["ALICE", "BOB", "CHARLIE"]

swift
class Product {
    var name: String
    var price: Double
    
    init(name: String, price: Double) {
        self.name = name
        self.price = price
    }
}
let products = [Product(name: "iPhone", price: 699), Product(name: "iPad", price: 999), Product(name: "MacBook", price: 1299)]

swift
let discountedPrices = products.map { product in
    let discountedPrice = product.price * 0.9
    return Product(name: product.name, price: discountedPrice)
}
print(discountedPrices) // 输出 [Product(name: "iPhone", price: 629.1), Product(name: "iPad", price: 899.1), Product(name: "MacBook", price: 1169.1)]

swift
let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
let evenNumbers = numbers.map { $0 }.filter { $0 % 2 == 0 }
print(evenNumbers) // 输出 [2, 4, 6, 8, 10]