VPython 6-对象不会删除

Question

I have a 3D elastic collision simulation. I'd like to clear all of the sphere objects from my program from a button press. The documentation indicates that I should do the following:

def clear_balls():
   for ball in balls:
      ball.visible = False
      del ball

This successfully makes the balls invisible in the scene, but they still take up memory and collide with balls that still exist. I want it completely removed. Trying this with a unique ball name this isn't part of a list as some have suggested still results in the same issue.

Answer 1

del ball is not doing what you think because balls still holds a reference to the object. You need to empty the balls list:

def clear_balls():
    for ball in balls:
        ball.visible = False
     balls[:] = []