python - 类实例不可迭代

Question

在我的函数中，我有:

        """
        Iterates 300 times as attempts, each having an inner-loop
        to calculate the z of a neighboring point and returns the optimal                 
        """

        pointList = []
        max_p = None

        for attempts in range(300):

            neighborList = ( (x - d, y), (x + d, y), (x, y - d), (x, y + d) )

            for neighbor in neighborList:
                z = evaluate( neighbor[0], neighbor[1] )
                point = None
                point = Point3D( neighbor[0], neighbor[1], z)
                pointList += point
            max_p = maxPoint( pointList )
            x = max_p.x_val
            y = max_p.y_val
        return max_p

我没有遍历我的类实例，但我仍然得到:

    pointList += newPoint
TypeError: 'Point3D' object is not iterable

Answer 1

问题是这一行:

pointList += point

pointList 是一个 list 而 point 是一个 Point3D 实例。您只能将另一个可迭代对象添加到可迭代对象。

你可以用这个修复它:

pointList += [point]

或

pointList.append(point)

在您的情况下，您不需要将None 分配给point。您也不需要将变量绑定(bind)到新点。您可以像这样将其直接添加到列表中:

pointList.append(Point3D( neighbor[0], neighbor[1], z))