Question

因此，我使用CloudKit并将所有数据作为[StartDay]提取到数组中，我的StartDay类如下所示：

import UIKit
import CloudKit

class StartDay {

var recordID: CKRecord.ID!
var wakeUp: String!
var sleptWell: String!
var dNN: String!
var created: String! {

    get { 
        return created
    }
}
}`

我的函数加载得到一个arraylist，其中包含从数据库接收的信息。在我的数据库中，它是这样的：“ 22.01.09：

    func checkIfButtonShouldBeEnabled(startDayList: [StartDay]){

    let startDayDates = startDayList.map{$0.created}

    for i in 0..<startDayDates.count {

        print(startDayDates)

    }

}`

输出：可选（“ 22.01.2019”）可选（“ 22.01.2019”）

我想删除“ Optional（）”，所以只显示“ 22.01.2019”，我该怎么做？

更新：获取功能

func loadStartDay() -> [StartDay]{

    let predicate = NSPredicate(value: true)
    let query = CKQuery(recordType: "StartDay", predicate: predicate)
    let operation = CKQueryOperation(query: query)

    var startDays: [StartDay] = []
    operation.desiredKeys = ["wakeUp", "wellSlept", "dNN", "recordID", "createdDato"]

    operation.recordFetchedBlock = { (record:CKRecord) in
        let newStartDay = StartDay()

        newStartDay.wakeUp = record.object(forKey: "wakeUP") as? String
        newStartDay.sleptWell = record.object(forKey: "sleptWell") as? String
        newStartDay.dNN = record.object(forKey: "dNN") as? String
        newStartDay.recordID = record.object(forKey: "recordID") as? CKRecord.ID
        newStartDay.created = record.object(forKey: "createdDato") as? String

        print(newStartDay.created)

        startDays.append(newStartDay)

    }

Answer 1

您可以使用print(startDayDates!)或print(startDayDates ?? "default value")。

但是我建议使用startDayList.compactMap()而不是startDayList.map()，以确保您的数组不包含nil值。

您也可以这样：

startDayList
    .compactMap { $0.created }
    .forEach { print($0) }

Answer 2

您设计了您完全了解的数据库模型，其中记录属性始终存在。将类属性声明为隐式，未包装的可选属性（例如，不在写初始化程序的不在场证明）是非常糟糕的做法。

假设记录中的每个属性确实都有一个值，将这些属性声明为非可选属性，然后编写一个初始化程序。

至少created和recordID应该总是有一个值！

import UIKit
import CloudKit

class StartDay {

    var recordID: CKRecord.ID
    var wakeUp: String
    var sleptWell: String
    var dNN: String
    var created: String 

    init(record : CKRecord) {
        // recordID can be retrieved directly
        self.recordID = record.recordID
        self.wakeUp = record.object(forKey: "wakeUP") as! String
        self.sleptWell = record.object(forKey: "sleptWell") as! String
        self.dNN = record.object(forKey: "dNN") as! String
        self.created = record.object(forKey: "createdDato") as! String
    }
}

并使用

创建实例

operation.recordFetchedBlock = { record in
    startDays.append(StartDay(record: record))
}

现在Optional已经消失了。

print(startDayList.map{ $0.created })

如何从数组中的对象中删除“ Optional（）”

2 个答案: