title: How to clear Tkinter Canvas?
body: <p>When I draw a shape using:</p>
  
  <pre><code>canvas.create_rectangle(10, 10, 50, 50, color="green")
  </code></pre>
  
  <p>Does Tkinter keep track of the fact that it was created? </p>
  
  <p>In a simple game I'm making, my code has one <code>Frame</code> 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. </p>
  
  <p>Am I creating thousands of rectangle objects in memory? </p>
  
  <p>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?</p>