Swift：在不使用索引的情况下从数组中删除有限数量的对象

Question

我有以下数组：

let chPizza = ["type": "deep", "Style" : "Chicago", "Size" : 12]
let nyPizza = ["type": "thin", "Style" : "New York", "Size" : 14]
let caPizza = ["type": "thai", "Style" : "California", "Size" : 12]
let gkPizza = ["type": "thick", "Style" : "Greek", "Size" : 16]


var pizzas = [chPizza, chPizza, gkPizza, nyPizza, caPizza, chPizza, chPizza, gkPizza, caPizza, chPizza]

如何删除chPizza 的前三个元素？我必须使用旧的 for 循环，还是可以使用高阶函数？

Answer 1

让我们创建自己的高阶方法：

extension Array where Element:Equatable {
    mutating func removeObject(obj:Element) {
        if let ix = self.indexOf(obj) {
            self.removeAtIndex(ix)
        }
    }
}

好的，我们开始；它现在是单行的（但请注意，我们必须强制转换为 NSDictionary，因为 Swift 字典不是 Equatable ，因此您无法在数组中找到一个）：

let chPizza = ["type": "deep", "Style" : "Chicago", "Size" : 12]
let nyPizza = ["type": "thin", "Style" : "New York", "Size" : 14]
let caPizza = ["type": "thai", "Style" : "California", "Size" : 12]
let gkPizza = ["type": "thick", "Style" : "Greek", "Size" : 16]

var pizzas : [NSDictionary] = [chPizza, chPizza, gkPizza, nyPizza, caPizza, chPizza, chPizza, gkPizza, caPizza, chPizza]

(0..<3).forEach {_ in pizzas.removeObject(chPizza)}

请注意，这是低效的！但是如果数组很小并且我们删除的次数很少，我们可以负担得起。