Tkinter - Listbox

https://stackoverflow.com/questions/14362116/python-tkinter-multiple-selection-listbox

INTRODUCTION

Listboxes are used to select from a group of textual items. Depending on how the listbox is configured, the user can select one or many items from that list.

# listbox1.py
import tkinter as tk

root = tk.Tk()   # root widget

listbox = tk.Listbox(root, selectmode=tk.MULTIPLE) # empty listbox
listbox.grid()

listbox.insert(tk.END, "a list entry")   # adding the first entry

for item in ["one", "two", "three", "four"]:
    listbox.insert(tk.END, item)

button = tk.Button(root, text="Choices", command=lambda:
    print([listbox.get(i) for i in listbox.curselection()]))
button.grid()

root.mainloop()

Selected keyword arguments in Listbox()

master=root     # the first argument
selectmode=tk.BROWSE   # the user can select only a single item (default)
selectmode=tk.MULTIPLE   # other: tk.SINGLE, tk.EXTENDED
width=20   # the width of the widget in characters (default is 20)
height=10   # number of lines shown in the listbox (default is 10)
relief=tk.SUNKEN   # default
listvariable=listvar   # a variable that holds the list of items contained in the listbox
yscrollcommand   # used to connect the listbox to a scrollbar's "set" method

Methods in Listbox()

listbox.insert(pos, item)   # pos can be number or tk.END (first available) or tk.ACTIVE
listbox.get(pos)
listbox.delete(pos)
listbox.delete(0, tk.END)   # delete range
listbox.curselection()   # return a tuple with selections

listbox.selection_set(pos)   # then use see(pos)
listbox.see(pos)

# Using listvariable.

# Items for listbox.
days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]

listvar = tk.StringVar(value=days)

listbox = tk.Listbox(root, listvariable=listvar)
listbox.grid()

# Changing items.
days.remove("Monday")
days.append("Monday")
listvar.set(days)