为什么4个对象显示数组中是否有3个对象？

Question

我正在从解析中检索对象并将它们插入到数组中并将它们放在视图中，但由于某种原因，即使数组中只有3个对象，也会显示4个对象。我该如何解决这个问题？

   func locationsSet(){


    for (index, users) in upimage.enumerate() {

        let userbutton = UIButton()
        userbutton.addTarget(self, action: "buttonAction:", forControlEvents: .TouchUpInside)
        userbutton.frame = CGRectMake(100, 100, 50, 50)
        userbutton.layer.cornerRadius = userbutton.frame.size.width/2
        userbutton.clipsToBounds = true
        userbutton.setImage(users, forState: .Normal)

        let radians = CGFloat(M_PI) * 2.0 / CGFloat(upimage.count) * CGFloat(index)

        let centerx = self.view.bounds.width / 2.0
        let radius =  currentuserpic.frame.size.width / 2.0
        let centery = self.view.bounds.height / 2.0

        let pointx = centerx + cos(radians) * (radius + 40)
        let pointy = (centery) + (sin(radians)) * (radius + 40)

        userbutton.center.x = pointx
        userbutton.center.y = pointy

        self.userbutton.append(userbutton)
        self.view.addSubview(userbutton)

        print("x\(pointx)")
        print("y\(pointy)")
        print(upimage.count)

    }