How to remove the text from label when checkbutton is not being checked? - checkbox

Question

i'm working on this code.i want to make it display the text from the checkbutton on the label, and also remove the text when the checkbutton is not being checked.the first question is i can't remove it since the system responses
TypeError: list indices must be integers or slices, not str
the other question is i want to make a shuffle button which can shuffle the text in the label.i tried random.shuffle() but it seems doesn't work. thanks in advance!!
import tkinter as tk
import random
window = tk.Tk()
checkbutton_frame = tk.Frame(window)
checkbutton_frame.grid(column=0, row=1)
contentvar = tk.StringVar()
label = tk.Label(window, textvariable=contentvar,
bg='white', font=('Arial', 10), width=20, height=20, wraplength=50)
label.grid(column=6, row=1, padx=20,
pady=20, columnspan=2)
cb_list = ['ray', 'kevin', 'jacky']
cb_vars = []
checked = []
check_list = 1
def display():
for text, var in zip(cb_list, cb_vars):
if var.get():
checked.append(text)
contentvar.set(list(set(checked)))
else:
for i in checked:
del checked[i]
def shuffle():
random.shuffle(checked)
for r, element in enumerate(cb_list):
var = tk.BooleanVar(window, False)
cb = tk.Checkbutton(checkbutton_frame, variable=var,
text=element, command=display)
cb.grid(column=check_list, row=r, sticky='w')
cb_vars.append(var)
shuffle_button = tk.Button(window, text='SHUFFLE', command=shuffle)
shuffle_button.grid(column=8, row=2)
window.mainloop()

Answer 1

In the function display() you have:
else:
for i in checked:
del checked[i]
but checked is a string, so i will be a string. Try:
for i, dummy in enumerate(checked):
There were a few more things: the function display() appends to the list checked for checked items even if they are already there. This makes it look like the delete does not work. You can't see that you have to many of any item as you put them through a set before you load them into the label as set doesn't allow identical items.
Then you should set the contentvar after all processing, i.e. last in the function. Here's a version that works:
def display():
for text, var in zip(cb_list, cb_vars):
if var.get():
if text not in checked:
checked.append(text)
else:
if text in checked:
checked.remove(text)
contentvar.set(checked)
Now the texts in the label appear in the order you put them there.
The function shuffle() works just fine and shuffles the list checked. But you will have to load it into the label as well:
def shuffle():
random.shuffle(checked)
contentvar.set(checked)