[python] How to clear Tkinter Canvas?

When I draw a shape using:

canvas.create_rectangle(10, 10, 50, 50, color="green")

Does Tkinter keep track of the fact that it was created?

In a simple game I'm making, my code has one Frame create a bunch of rectangles, and then draw a big black rectangle to clear the screen, and then draw another set of updated rectangles, and so on.

Am I creating thousands of rectangle objects in memory?

I know you can assign the code above to a variable, but if I don't do that and just draw directly to the canvas, does it stay in memory, or does it just draw the pixels, like in the HTML5 canvas?

Yes, I believe you are creating thousands of objects. If you're looking for an easy way to delete a bunch of them at once, use canvas tags described here. This lets you perform the same operation (such as deletion) on a large number of objects.

Items drawn to the canvas are persistent. create_rectangle returns an item id that you need to keep track of. If you don't remove old items your program will eventually slow down.

From Fredrik Lundh's An Introduction to Tkinter:

Note that items added to the canvas are kept until you remove them. If you want to change the drawing, you can either use methods like coords, itemconfig, and move to modify the items, or use delete to remove them.