python - Tkinter access Canvas Objects created by Loop outside the loop

Question

I am trying to manipulate some Canvas objects created by a loop on the Tkinter Canvas. Unfortunately I cannot access the the coordinates of these rectangles outside the loop, only one of them. How can I access all of the rectangles created by the loop outside the loop to get their coordinates, as well as manipulate them? This question might not make sense so please ask me if you don't understand and I will try to explain it better. Thanks!

    for y in range(2):
        for x in range(2):
            x1 = x*230
            y1 = y*230
            height = x1 + 200
            width = y1 + 200
            music_catalog_rect = canvas.create_rectangle((x1, y1, height, width), fill='red')
            canvas.move(music_catalog_rect, 180, 20)

Answer 1

You should store the items in some sort of data structure. You can then iterate over the structure to pick out specific values or iterate over all of the values.

For example, you might store them in a list:

rects = []
for y in range(2):
    for x in range(2):
        ...
        item = canvas.create_rectangle(...)
        rects.append(item)
        ...

This allows you to easily iterate over all of the items:

for item in rects:
    canvas.move(item, ...)

If keeping the x,y data is important, you can use the x,y as a key to a dictionary:

rects = {}
for y in range(2):
    for x in range(2):
        ...
        item = canvas.create_rectangle(...)
        rects[(x,y)] = item
        ...

Then later, you do something like the following:

canvas.move(rects[(3,4)], ...)