ios - 不可变值类型 [string] 只有名为 append 的可变成员

Question

我正在尝试将一个新的 Store 对象附加到我的 User 结构中的 stores 数组中...我向我的 Struct 添加了一个可变的 func append 但我仍然遗漏了一些东西，因为我仍然得到了

Immutable value type [Store] only has mutating members named 'append'

错误

import Foundation

import UIKit

struct User {
    var name: String
    var stores: [Store]



    mutating func append(newStore: Store) {
        stores.append(newStore)
    }
}

extension User: Printable {
    var description: String {
        var printedName = ("\(name as String, stores as [Store])")
        return printedName
    }
}

struct Store {
    var name: String
    var data: [[String: String]]



}

extension Store: Printable {
    var description: String {
        var printedStores = ("\(name as String, data as [[String : String]])")
        return printedStores
}
}

 @IBAction func done(segue: UIStoryboardSegue) {
        let addStoreViewController = segue.sourceViewController as! AddStoreViewController
        let store = addStoreViewController.store
        if let selectedIndex = addStoreViewController.index {
            stores[selectedIndex] = store!
        } else {
            if let selectedUser = user {
                selectedUser.stores.append(store!)
            }
        }
        storeTableView.reloadData()
    }

import UIKit

class AddStoreViewController: UIViewController {


    var store: Store?
    var index: Int?

    @IBOutlet weak var storeTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

        if let name = store?.name {
            storeTextField?.text = name
        }

        // Do any additional setup after loading the view.
    }





    // MARK: - Navigation


    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        let name = storeTextField?.text
        if segue.identifier == "addAction" {
            if var store = store {
                self.store?.name = name!
            } else {
                store = Store(name: name!, data: [["": ""]])
                println(store) 
            }
        }
    }



}

Answer 1

试试这个

if var selectedUser = user {
    selectedUser.append(store!)
}

append函数属于struct user，不属于user.stores