Swift 2 - 创建数组数组

Question

我正在尝试创建一个包含多个数组的数组。我正在使用 CloudKit 来获取数据。

import UIKit
import CloudKit

var questionsCount = 0
var questionsArray = [String]()

class hvadvilduhelstViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    //firstfield.setTitle("Klik her for at starte!", forState: .Normal)
    //secondfield.setTitle("Klik her for at starte!", forState: .Normal)
    firstfield.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
    firstfield.titleLabel?.textAlignment = NSTextAlignment.Center
    secondfield.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
    secondfield.titleLabel?.textAlignment = NSTextAlignment.Center

    let container = CKContainer.defaultContainer()
    let publicData = container.publicCloudDatabase

    let query = CKQuery(recordType: "Questions", predicate: NSPredicate(format: "TRUEPREDICATE", argumentArray: nil))
    publicData.performQuery(query, inZoneWithID: nil) { results, error in
        if error == nil { // There is no error
            for entry in results! {
                let firstOne = [entry["Question1"] as! String]
                let secondOne = firstOne + [entry["Question2"] as! String]
                let thirdOne = secondOne + [String(entry["Question1Rating"] as! Int)]
                let fourthOne = thirdOne + [String(entry["Question2Rating"] as! Int)]
                let fithOne = fourthOne + [String(entry["Reports"] as! Int)]
                questionsArray = questionsArray + fithOne
                print(questionsArray)

            }

        }
        else {
            print(error)
        }
    }

}

使用以前的代码，我在控制台输出中得到了这个：

["Dette er en test1", "Dette er en test2", "0", "0", "0", "test2", "test2", "0", "0", "0"]

而不是这个（这是我想要的输出）：

[["Dette er en test1", "Dette er en test2", "0", "0", "0"], ["test2", "test2", "0", "0", "0"]]

我只是不知道该怎么做。我的计划是获取大量记录并将它们放入这个单一的巨大数组中（以便于使用 'value'）是否有 easier/better 方法可以做到这一点？

对不起我的英语，不是我的母语。感谢您的帮助！

Answer 1

当你遇到这样的问题时，制作一个游乐场并进行实验并进行一些思考。本质上，这就是您正在做的事情：

var arr = [String]()
for _ in (1...3) {
    let first = ["Mannie"]
    let second = first + ["Moe"]
    let third = second + ["Jack"]
    arr = arr + third
}
arr // ["Mannie", "Moe", "Jack", "Mannie", "Moe", "Jack", "Mannie", "Moe", "Jack"]

那不是你想要的，所以不要那样做。首先，正如您的问题标题所说，您需要一个数组数组。那么，您不想以 [String] 结束；你刚刚告诉我们你想要一个 [[String]] （字符串数组的数组）！所以首先进行更改：

var arr = [[String]]()

现在，当您构建数组并将其插入数组数组时，请使用 append 方法（而不是 + 运算符）：

arr.append(third)

结果如下：

var arr = [[String]]()
for _ in (1...3) {
    let first = ["Mannie"]
    let second = first + ["Moe"]
    let third = second + ["Jack"]
    arr.append(third)
}
arr // [["Mannie", "Moe", "Jack"], ["Mannie", "Moe", "Jack"], ["Mannie", "Moe", "Jack"]]

现在开始吧，在你的真实代码中做同样的事情。

Answer 2

试试这个：

import UIKit
import CloudKit

var questionsCount = 0
var questionsArray = [[String]]()

class hvadvilduhelstViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        //firstfield.setTitle("Klik her for at starte!", forState: .Normal)
        //secondfield.setTitle("Klik her for at starte!", forState: .Normal)
        firstfield.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
        firstfield.titleLabel?.textAlignment = NSTextAlignment.Center
        secondfield.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
        secondfield.titleLabel?.textAlignment = NSTextAlignment.Center

        let container = CKContainer.defaultContainer()
        let publicData = container.publicCloudDatabase

        let query = CKQuery(recordType: "Questions", predicate: NSPredicate(format: "TRUEPREDICATE", argumentArray: nil))
        publicData.performQuery(query, inZoneWithID: nil) { results, error in
            if error == nil { // There is no error
                for entry in results! {
                    let firstOne = entry["Question1"] as! String
                    let secondOne = entry["Question2"] as! String
                    let thirdOne = String(entry["Question1Rating"] as! Int)
                    let fourthOne = String(entry["Question2Rating"] as! Int)
                    let fifthOne = String(entry["Reports"] as! Int)
                    questionsArray.append([firstOne, secondOne, thirdOne, fourthOne, fifthOne])
                    print(questionsArray)
                }
            }
            else {
                print(error)
            }
        }
    }
}

值得注意的是，questionsArray 现在是 [[String]] 类型，而不仅仅是 [String]，并且对于每个 entry，您想要附加一个新的 [String]

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