如何在Swift中将一个数组附加到另一个数组？

Question

我有一个JSON响应，我需要解析它。我使用for循环将单个元素写入名为courseDataArray的数组中。之后，我想要将这个新创建的数组写入另一个名为combinedCourseArray的数组中，以便将其传递给UITableView。创建第一个数组似乎运行良好。但如何创建另一个数组combinedCourseArray，其中包含所有类型为courseDataArray的数组？

for (index, element) in result.enumerate() {

            // get one entry from the result array
            if let courseEntry = result[index] as? [String:AnyObject]{

                //work with the content of the array
                let courseName = courseEntry["name"]
                let courseType = courseEntry["course_type"]
                let courseDate = courseEntry["cor_date"]
                let courseId = courseEntry["cor_id"]
                let duration = courseEntry["duration"]
                let schoolId = courseEntry["sco_id"]
                let status = courseEntry["status"]


                let courseDataArray = ["courseName" : courseName, "courseType": courseType, "courseDate": courseDate, "courseId": courseId, "duration": duration, "schoolId":schoolId, "status":status]

                print(courseDataArray)

                var combinedCourseArray: [String: AnyObject] = [:]
                combinedCourseArray[0] = courseDataArray //does not work -- error: cannot subscript a value of type...

               // self.shareData.courseStore.append(scooter)

            }

- Stefan Badertscher

---

combinedArray 应该是 [[String: AnyObject]] 类型，因为它是一个 Array<[String:AnyObject]>。请使用 var combinedCourseArray: [[String: AnyObject]] = [[:]]。 - Khundragpan

[String: AnyObject] 是字典而不是数组。 - Nirav D

谢谢，那就是问题所在。我必须在 AnyObject 后面添加 ? ：var combinedCourseArray: [[String: AnyObject?]] = [[:]] - Stefan Badertscher

顺便提一下，courseDataArray 实际上是一个 Dictionary 而不是一个 Array。 - David Berry

Answer 1

您应该将combinedCourseArray声明移至数组之外。它应该是var combinedCourseArray: [[String: AnyObject]] = [[:]]，因为它是一个数组而不是字典。

同时，您应该执行

combinedCourseArray.append(courseDataArray)

替代

combinedCourseArray[0] = courseDataArray

- Wyetro

---

谢谢，运行良好。我不得不在这里添加问号：var combinedCourseArray: [[String: AnyObject?]] = [[:]] - Stefan Badertscher

Answer 2

var FirstArray = [String]()
var SecondArray = [String:AnyObject]()

FirstArray.append(contentsOf: SecondArray.value(forKey: "key") as! [String])

- Shakeel Ahmed

Answer 3

首先在这个循环之外声明 combinedCourseArray 数组

var combinedCourseArray: [[String: AnyObject]] = [[String: AnyObject]]()
for (index, element) in result.enumerate() {

        // get one entry from the result array
        if let courseEntry = result[index] as? [String:AnyObject]{

            //work with the content of the array
            let courseName = courseEntry["name"]
            let courseType = courseEntry["course_type"]
            let courseDate = courseEntry["cor_date"]
            let courseId = courseEntry["cor_id"]
            let duration = courseEntry["duration"]
            let schoolId = courseEntry["sco_id"]
            let status = courseEntry["status"]


            let courseDataArray = ["courseName" : courseName, "courseType": courseType, "courseDate": courseDate, "courseId": courseId, "duration": duration, "schoolId":schoolId, "status":status]

            print(courseDataArray)


            combinedCourseArray.append(courseDataArray) //does not work -- error: cannot subscript a value of type...

           // self.shareData.courseStore.append(scooter)

        }
 }

- Nirav D

---

谢谢，运行良好。我不得不在这里添加问号：var combinedCourseArray: [[String: AnyObject?]] = [[:]] - Stefan Badertscher

Answer 4

只需在外部数组上使用flatMap，将一个数组转换为另一个数组，可能会删除一些元素：

let courseDataArray : [[String:AnyObject?]] = result.flatMap {
    guard let courseEntry = $0 as? [String:AnyObject] else {
        return nil
    }

    return [
        "courseName" : courseEntry["name"],
        "courseType": courseEntry["course_type"],
        "courseDate": courseEntry["cor_date"],
        "courseId": courseEntry["cor_id"],
        "duration": courseEntry["duration"],
        "schoolId": courseEntry["sco_id"],
        "status": courseEntry["status"]
    ]
}

当然，由于输入类型已经是[[String:AnyObject]]，并且您不会遇到任何内部故障，因此警卫实际上并不必要，您只需使用map而不是flatMap即可。

- David Berry