ios - Swift 如何检查我是否遍历 List[String] 的最后一项

Question

我需要检查我何时遍历最后一项。我不能只把这一行放在我的 for 循环之后，因为那样我总是收到一个空列表。我尝试了以下但这个不起作用:

   .observeSingleEvent(of: .value, with: { (snapshot) in
            if snapshot.exists(){

                for rest in snapshot.children.allObjects.count as! [DataSnapshot] {
                    let refi = Database.database().reference().child("Users")
                    refi.observeSingleEvent(of: .value, with: { (snapshoti) in
                        if snapshoti.value as! String == "active"{

                            let userid = rest.key
                            self.someProtocol[rest.key] = self.checksum

                            if self.checksum == self.someProtocol.count-1 {
                                self.sortUsers()
                            }else{

                            }
                            self.checksum = self.checksum+1


                        }

                    })

                }

Answer 1

dr_barto 的答案可行，但需要进行以下调整:

    for (idx, element) in array.enumerated() {
      if idx == array.endIndex-1 {
        // handling the last element
       }
     }

来自 Apple 文档:

endIndex is the array’s “past the end” position—that is, the position one greater than the last valid subscript argument