How do you pull out variables from a Tkinter Listbox to use elsewhere in your script?

Question

So I have a listbox Tkinter object in python that allows me to select multiple items and it prints out the index of what items where selected. I want to use that index to match elsewhere in my script to say something like, if item 0,2,4 were selected then run this set of code or show other attributes of the table for 0,2,4 and exclude items 1 and 3.

Here is my script:

Title = ["ABC","DEF","GHI","JKL","MNO"]

def select_title():
    print(title_list.curselection())
    root.destroy()

root = Tk()
title_list = Listbox(root, width = 100, selectmode = MULTIPLE)
i = 0
while i < len(Title):
    title_list.insert(END, Title[i])
    i += 1
title_list.pack()

my_button = Button(root, text="Select", command=select_title)
my_button.pack()

root.mainloop()

When I run it, I get this:

If I select "ABC", "GHI" & "MNO" (indexed of 0,2,4) and press the select button I get this output printed out:

(0, 2, 4)

I want to use these for a list = [0, 2, 4] that I can index elsewhere and that is what I am having trouble figuring out. I tried putting a return function in there but that doesn't seem to work when working with this format of Tkinter objects. I would really appreciate any insight that anyone could provide. Thanks!

Update: If I adjust the code to this, see below, I still can't use the list outside the def:

Title = ["ABC","DEF","GHI","JKL","MNO"]

def select_title():
    print(title_list.curselection())
    sel = title_list.curselection()
    lst = [_ for _ in sel]
    print(lst)
    root.destroy()

root = Tk()
title_list = Listbox(root, width = 100, selectmode = MULTIPLE)
i = 0
while i < len(Title):
    title_list.insert(END, Title[i])
    i += 1
title_list.pack()

my_button = Button(root, text="Select", command=select_title)
my_button.pack()

root.mainloop()

Output:

(0, 2, 4)
[0, 2, 4]

Trying outside the def:

lst

Output:

Assign a variable to that, like `sel = title_list.curselection()` and then `lst = [_ for _ in sel]`, now `lst` is index of those selection. — Delrius Euphoria, Nov 20 '20 at 19:57
This doesn't work the way I am trying to use it. I still can't use the list outside the def. I want to be able to do that. So say I go to a new markdown line in Jupyter notebooks and type "lst" I would get the output of "[0,2,4]. Please see my update above. — Andrew Hicks, Nov 20 '20 at 20:12

score 0 · Answer 1 · answered Nov 20 '20 at 20:21

Thank you Cool Cloud for your insight. It was crucial to get this to work.

Below is the script that worked:

Title = ["ABC","DEF","GHI","JKL","MNO"]

def select_title():
    sel = title_list.curselection()
    global lst
    lst = [_ for _ in sel]
    root.destroy()

root = Tk()
title_list = Listbox(root, width = 100, selectmode = MULTIPLE)
i = 0
while i < len(Title):
    title_list.insert(END, Title[i])
    i += 1
title_list.pack()

my_button = Button(root, text="Select", command=select_title)
my_button.pack()

root.mainloop()

lst

Just a tip your `while` loop can be changed to `for` loop, like `for i in Title: title_list.insert(END,i)` — Delrius Euphoria, Nov 20 '20 at 20:22

How do you pull out variables from a Tkinter Listbox to use elsewhere in your script?

1 Answers1