添加唯一值我在解析服務器陣列（SWIFT 3）

Question

我的解析服務器有一個名爲「BooksAddedByUser」類，它有3列：

1. OBJECTID
2. 用戶 - 包含PFUser的用戶名.current（）
3. ISBNArray - 圖書用戶

加我想補充新添加的bookNumber到ISBNArray只有當它沒有在數組中還存在的ISBN。但是，無論何時我在下面運行我的代碼，它都會在「BooksAddedByUser」類中使用相同的用戶名創建新的objectIds。而且它也不檢查bookNumber是否已經存在。我不確定實際情況如何。

let booksAddedByUser = PFObject(className: "BooksAddedByUser") 
    booksAddedByUser["user"] = PFUser.current()?.username 

    let query = PFQuery(className: "BooksAddedByUser") 
    query.whereKey("ISBNArray", contains: bookNumber) 
    query.findObjectsInBackground { (objects, error) in 
     if error != nil { 
      print(error) 
     } else { 
      print(self.bookNumber) 

      if let objects = objects { 
       for object in objects { 
        print("book is already added i think") 
       } 
      } 
     } 
    } 

booksAddedByUser.addObjects(from: [bookNumber], forKey: "ISBNArray") 

booksAddedByUser.saveInBackground { (success, error) in 
    if error != nil { 
     print("error saving new book") 
    } else { 
     print("new book saved!") 
    } 
} 

編輯瓦特/新代碼：

let booksAddedByUser = PFObject(className: "BooksAddedByUser") 
    booksAddedByUser["user"] = PFUser.current()?.username 


    let query = PFQuery(className: "BooksAddedByUser") 
    query.findObjectsInBackground { (objects, error) in 
     if error != nil { 

      print(error) 

     } else { 

      print(self.bookNumber) 

      if let objects = objects { 

       if objects.contains(bookNumber) { 

        print("book exists") 


       } 

      } 

     } 
    } 

    booksAddedByUser.addObjects(from: [bookNumber], forKey: "ISBNArray") 

    booksAddedByUser.saveInBackground { (success, error) in 

     if error != nil { 

      print("error saving new book") 

     } else { 

      print("new book saved!") 

     } 

    } 

Answer 1

你可以，如果一個對象退出陣列中使用此檢查：

if arrObjects.contains(where: { $0.bookNumberPropertyName == "bookNumber" }) { 
    print("Book exists") 
}