类实例不可迭代

Question

在我的功能中,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

我没有迭代我的类实例,指出,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并且point是一个Point3D实例.您只能将另一个iterable添加到iterable中.

你可以解决这个问题:

pointList += [point]

要么

pointList.append(point)

在你的情况并不需要分配None给point.您也不需要将变量绑定到新点.您可以将它直接添加到列表中,如下所示:

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