ios - 将不同的数组合并到另一个数组中

Question

struct Product {
    let id: String
    let quantity: Int
    let price: Double
}

class ProductPrices {

    internal static var PricesArray : [String:Double] = ["product1": 5.00,"product2": 5.00,"product3": 5.00]

}

class ProductNames {

    internal static var NamesArray : [String:String] = ["product1": "name1","product2": "name2","product3": "name3"]

}

我有这个数组

["product1","product1","product2,"product1","product3","product2"]

我的问题是如何将这些项目放入 Product

预期结果:

Product(id: "name1", quantity: 3, price: 15.00)
Product(id: "name2", quantity: 2, price: 10.00)
Product(id: "name3", quantity: 1, price: 5.00)

Answer 1

输入

所以我们有一个结构

struct Product {
    let id: String
    let quantity: Int
    let price: Double
}

我们还有 2 个字典和 1 个数组

let prices = ["product1": 5.00, "product2": 5.00, "product3": 5.00]
let names = ["product1": "name1","product2": "name2","product3": "name3"]
let elms = ["product1", "product1", "product2", "product1", "product3", "product2"]

输出

现在我们要使用以下逻辑构建一个 Product(s) 数组

1. Product.id 从 names
中获取
2. Product.quantity 是 Product.id 在 elms
中出现的次数
3. Product.price 是产品的价格 * 数量

我们可以这样写

let products = names.compactMap { elm -> Product? in
    let name = elm.value
    let id = name
    let quantity = elms.filter { $0 == elm.key }.count
    guard quantity > 0, let price = prices[elm.key] else { return nil }
    return Product(id: id, quantity: quantity, price: price * Double(quantity))
}

测试

[
    Product(id: "name2", quantity: 2, price: 10.0),
    Product(id: "name1", quantity: 3, price: 15.0),
    Product(id: "name3", quantity: 1, price: 5.0)
]

The compactMap method is available in Swift 4.1. For previous versions of Swift please use flatMap.