How do I stop my tkinter animation from disappearing at the end of my loop?

Question

As the title states, how do I stop the images in an animation made in tkinter from disappearing?

I have my code here:

ballx1 = 100
bally1 = 500
speed=10

for frames in range(300):
    rectangle = s.create_rectangle(ballx1,bally1,ballx1+100,bally1+200,fill='red')
    s.update()
    sleep(0.0333)
    s.delete(rectangle)
    if(bally1 >= 600):
        speed=speed * -1
    if bally1<=0:
        speed=speed * -1
    bally1=bally1-speed

How would I prevent the screen from going black at the end of the loop?

I have attempted altering the delete line to this,

if frames<=299:
        s.delete(rectangle)

, but the screen still goes black in the end.

Answer 1

You should not create and delete the rectangle to move it. Instead create the rectangle once and just move it inside the for loop using .coords():

# create the rectangle
rectangle = s.create_rectangle(ballx1, bally1, ballx1+100, bally1+200, fill='red')

for frame in range(300):
    s.update()
    sleep(0.0333)
    if bally1 >= 600 or bally1 <= 0:
        speed *= -1
    bally1 -= speed
    # move the rectangle
    s.coords(rectangle, ballx1, bally1, ballx1+100, bally1+200)

However it is not recommended to use for loop and sleep() in a tkinter application because it will block the tkinter mainloop() from handling pending events and updates. Better use after loop instead.

rectangle = s.create_rectangle(ballx1, bally1, ballx1+100, bally1+200, fill='red')

def animation(bally, speed, n=300):
    if n >= 0:
        if bally >= 600 or bally <= 10:
            speed *= -1
        bally -= speed
        s.coords(rectangle, ballx1, bally, ballx1+100, bally+200)
        s.after(33, animation, bally, speed, n-1)

# start the animation
animation(bally1, speed)