Tkinter print specified item from list in loop

Question

I've code like below:

from tkinter import *

root = Tk()
root.title("sample program")

def print_item_from_list(event):
    print(variable)

list = [1, 2, 3, 4, 5]
seclist = []
print(list)
for i in range(0,5):
    variable = list[i]
    sample = Label(text=variable)
    sample.pack()
    sample.bind('<Enter>', print_item_from_list)

root.mainloop()

What I want to achieve is that everytime my pointer enter label 'Sample', specified item form list is printed (i.e. when I hover over label '2', I want second object from my list to get printed). I tried already changing variable to list[i] (Just for tests if it would work) and creating second list and appending to it, but with no luck. My guess is it's somehow connected to Tkniter behaviour.

http://stackoverflow.com/questions/14259072/tkinter-bind-function-with-variable-in-a-loop — Billal Begueradj, Jul 25 '16 at 05:33

score 2 · Answer 1 · answered Jul 25 '16 at 06:21

With your code :

from tkinter import *

root = Tk()
root.title("sample program")

def print_item_from_list(event):
    print(event.widget.config("text")[-1])


list = [1, 2, 3, 4, 5]
seclist = []
print(list)
for i in range(0,5):
    variable = list[i]
    sample = Label(text=variable)
    sample.pack()
    sample.bind('<Enter>', print_item_from_list)

root.mainloop()

score 1 · Accepted Answer · answered Jul 25 '16 at 04:55

You can make use of closures:

for i in range(0,5):
    variable = list[i]
    sample = Label(text=variable)
    sample.pack()
    def connect_callback(variable):
        sample.bind('<Enter>', lambda event:print(variable))
    connect_callback(variable)

This creates a new callback function with a fixed value for each label. In your code, all callbacks refer to the same variable, but with this solution every callback has its own variable.

Tkinter print specified item from list in loop

2 Answers2