How to set a different command to each button, when buttons are created without names

Question

How can I set it so that all 10 buttons each have a different command using this code:

line1 = ['q','w','e','r','t','y','u','i','o','p']

for n in range(10):
        tkinter.Button(keyboard, text = line1[n], command = line1[n]).grid(column = n + 1, row = 0, padx = 1, pady = 1)

Current Code:

line1 = ['q','w','e','r','t','y','u','i','o','p']

functions = [lambda: q(), lambda: w(), lambda: e(), lambda: r(), lambda: t(), lambda: y(), lambda: u(), lambda: i(), lambda: o(), lambda: p()]
    buttons = []
    def q():
        buttons[0].destroy()
    def selectCallback(n):
        global functions
        global buttons
        if n > 1:
            functions[2](n)
        else:
            functions[n]()
    for n in range(10):
        buttons.append(tkinter.Button(keyboard, text = line1[n], command = lambda n = n: selectCallback(n)))
        buttons[n].grid(column = n + 1, row = 0, padx = 1, pady = 1)

When this is run it causes the error.

You ask about a "different command", but you're not referencing a command, you're referencing an element in a list. — Bryan Oakley, Jul 09 '15 at 16:26

maccartm · Accepted Answer · 2015-07-09T18:37:48.437

0

A callback for callbacks!

Probably not the most elegant solution but you can have one main function which decides which function to use based on the argument given by the button.

You will need to decide what each value of n will call.

EDIT: Changed code answer comment

import Tkinter

keyboard = Tkinter.Tk()
line1 = ['q','w','e','r','t','y','u','i','o','p']
buttons = []
def func0():

    print("This could be 0's function")
    buttons[0].destroy()

def func1():

    print("This could be 1's function")
    buttons[1].destroy()

def funcX(n):


    print("You get the idea...")
    buttons[n].destroy()

functions = [lambda: func0(), lambda: func1(), lambda n: funcX(n)]

def selectCallback(n):

    global functions
    global buttons
    # If `functions` is filled out for all elements you can neglect this 
    # if/else and simply call `functions[n]()`
    if n > 1:
        functions[2](n)
    else:
        functions[n]()

for n in range(10):
        buttons.append(Tkinter.Button(keyboard, text = line1[n], command = lambda n = n: selectCallback(n)))
        buttons[n].grid(column = n + 1, row = 0, padx = 1, pady = 1)

keyboard.mainloop()

Important points:

-Must keep a reference to the buttons to be able to delete them (buttons)

-Must call .grid() on a separate line so it does not return None for what should be the Button.

-If all you want to do is delete the buttons, this does not require a different function for each. This example is meant to illustrate how you could have 10 different functions as callbacks.

-Additionally, my example is simplified: for buttons [2:9] I only call one function and pass an index so that I don't have to write out 10 functions. If you want to do a different function that performs a different operation for each button, fill out the functions list properly and remove the if/else construct within selectCallback(n), and access each function directly by its index.

edited Jul 09 '15 at 18:37

answered Jul 09 '15 at 16:28

maccartm

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How could I make it so that the command removes the button that has been pressed? – matthaous54 Jul 09 '15 at 16:53
Do you know what I need to add to answer the question above – matthaous54 Jul 09 '15 at 17:16
Check out the new code/explanation. – maccartm Jul 09 '15 at 17:20
When I press one of the buttons, it comes up with an error saying that the global name 'functions' is not defined in the line that says: – matthaous54 Jul 09 '15 at 17:37
else: functions[n]() @maccartm – matthaous54 Jul 09 '15 at 17:38
Did you copy my code exactly (I've just removed the `type` call surrounding the first `functions[2](n)` as it was something I used for testing & useless. If you did there should be no problem, if not make sure functions is defined before `selectCallback` and that you include the `global functions` line – maccartm Jul 09 '15 at 18:39
Tried everything you've just said and it's still giving me the error – matthaous54 Jul 09 '15 at 19:00
Can you post your code either in your question or in a chat? – maccartm Jul 09 '15 at 20:04
Just edited the question to contain the code I currently have – matthaous54 Jul 09 '15 at 20:32
[I've moved this to chat](http://chat.stackoverflow.com/rooms/82880/set-different-command-to-each-button) to limit the amount of comments and edits that we have to make. – maccartm Jul 10 '15 at 15:43
Still giving me the error, but I'm going to try and figure it out myself, thank you so much for all the help you have given me, I really appreciate it. – matthaous54 Jul 10 '15 at 17:48
Check out the chatroom, it shows an alternative way of deleting the buttons if that's all you plan on doing. Best of luck – maccartm Jul 10 '15 at 18:41

How to set a different command to each button, when buttons are created without names

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