Question

我循环遍历整数对象并希望将每个整数添加到整数变量，然后在完成for循环时，打印总数。是否有捷径可寻？现在，我可以检索对象并单独打印它们，但每次打印总数为0。请参阅下面的代码。这是一个用Swift编写的应用程序，Parse作为后端。什么都有帮助，谢谢！

var itemsArray = [Int]()
let followingUserItemsQuery = PFUser.query()
followingUserItemsQuery?.whereKey("objectId", equalTo: (PFUser.currentUser()?.objectId!)!)
followingUserItemsQuery?.findObjectsInBackgroundWithBlock({ (objects: [PFObject]?, error) in
                if let objects = objects {
                for object in objects {
                let followingUsersArray = (object["following"] as! [String])
                // Get number of listed items of following users with PFUser query for their total objects
                    for followingUser in followingUsersArray {
                        print(followingUser)
                        let query = PFUser.query()
                        query?.whereKey("objectId", equalTo: followingUser)
                        //Get each user's listedItems count then append to a higher-level integer variable
                        query?.getFirstObjectInBackgroundWithBlock({ (object, error) in
                            itemsArray.append(object!["listedItems"] as! Int)
                        })
                    }
                }
            }
            let itemsSum = itemsArray.reduce(0, combine: +)
            print(itemsSum)
            self.followingUsersAddedItems.text = String("Your followers listed "+String(itemsSum)+" items")

Answer 1

试试这个：

var count = 0
...
for followingUser in followingUsersArray {
    count += object!["listedItems"] as! Int
}

Answer 2

减少/合并Int值的代码是正确的。问题是它在任何嵌套的异步Parse查询完成之前运行并执行它们的回调。所以当它运行时，itemsArray仍然是空的。您需要重新设计代码，以便在所有各种嵌套的Parse查询都已完成后，仅计算itemsSum。

在for循环中添加整数并打印总数

2 个答案: