arrays - Swift 4 将项目 append 到结构化数组中的特定部分

Question

我希望(根据此示例)在创建初始条目后将更多项目添加到结构化数组的特定部分。

struct Zoo {
    let section: String
    let items: [String]
}

var objects = [Zoo]()

let animals = Zoo(section: "Animals", items: ["Cat","Dog","Mouse"])
let birds = Zoo(section: "Birds", items: ["Crow","Pidgeon","Hawk"])

let reptiles = ["Snake","Lizard"]

objects.append(animals)
objects.append(birds)

// ... varous logic and proccessing where I determine I need 
// to add two more items to the animals section...

// trying to extend animals with two more entries.
// this is where I am getting hung up:
objects[0].items.append(reptiles)

Answer 1

删除以下代码

  objects[0].items.append(reptiles)

使用此代码:

objects[0].items +=  reptiles

Swift 5 更新:

在 Swift 5 中，此解决方案将不起作用，您将收到类似错误

"Left side of mutating operator isn't mutable: 'items' is a 'let'constant"

解决方案是改变结构:

struct Zoo {
    let section: String
    var items: [String]
}