如何在同一个数组中添加具有相同结束数的元素？ （Swift 3）

Question

我有我的代码在下面，我试图创建新的数组，每当用户添加一本书时，元素中的数字加1。例如，当用户已经有1本书加时，他又增加了一个数组应为["bookTitle2,"bookAuthor2", "bookPublisher2", "bookNumOfPages2"]

let bookDetails = ["bookTitle", "bookAuthor", "bookPublisher", "bookNumOfPages"] 
var bookDetail = "" 
var bookNumber = Int() 
var bookNumArray = [Int]() 

if bookNumArray.contains(bookNumber) { 

print("Book already exists") 

} else { 

while bookNumber < 2 { 

    bookNumber += 1 

    bookNumArray.append(bookNumber) 

    for detail in bookDetails { 

     bookDetail = "\(detail)" + String(bookNumber) 

     let newBookArray = [bookDetail] 

     print(newBookArray) 


    } 

} 


    } 

当我运行上面的代码，这反而说明了：

["bookTitle1"] 
["bookAuthor1"] 
["bookPublisher1"] 
["bookNumOfPages1"] 
["bookTitle2"] 
["bookAuthor2"] 
["bookPublisher2"] 
["bookNumOfPages2"] 

所以我想要所有以1结尾的字符串和另一个数组中以2结尾的字符串。

Answer 1

当你这样做：

for detail in bookDetails { 

    bookDetail = "\(detail)" + String(bookNumber) 

    let newBookArray = [bookDetail] 

    print(newBookArray) 
} 

对于每次迭代，您将创建一个新数组，其中包含当前详细信息，例如bookTitle到您的字符串var bookDetail的数组中，并在此循环范围之外声明。

另外请注意，newBookArray是一个局部变量，所以当它离开循环时它会被销毁。您需要一组bookDetail来存储newBookArray。

let bookDetails = ["bookTitle", "bookAuthor", "bookPublisher", "bookNumOfPages"] 
var bookDetailArray : [Array<String>] = [] //Your array to store all the bookDetails 
var bookDetail : [String] = [] //Your array to store a bookDetail 
var bookNumber = Int() 
var bookNumArray = [Int]() 

然后，你可以这样做：

bookDetail.removeAll() //Clear all objects before appending new one 

for detail in bookDetails { 

    bookDetail.append("\(detail) + String(bookNumber)") 
} 

bookDetailArray.append(bookDetail) 

只是一个建议：正如其他人表示，对于bookDetail性质字典或一类是你的情况更好的模式。如果您打算使用某个类，请阅读面向对象编程。

Answer 2

我会做一本字典或创建一个类BookDetails的属性，如bookTitle，bookAuthor等，然后我会创建一个这个类的实例的数组。

如果你想要做你的方式，为什么不创建一个双向阵列，是这样的：

var arrayFinal = [[""]] 
var bookNumber = 0 

// Whenever the action is triggered 

bookNumber += 1 

var bookDetails = ["bookTitle", "bookAuthor", "bookPublisher", "bookNumOfPages"] 

for detail in bookDetails 
{ 
    detail = "\(detail) +\(bookNumber)" 
} 

arrayFinal.add(bookDetails) 

或者类似的东西...