How do I pass a index of a list to a callback of a button?

Question

I am writing a GUI using tkinter, and I have several lines consisting of a Entry widget inline with a Button widget. When I press the button, the callback opens the askdirectory dialog, and the directory choosen is written in the Entry widget, from the same line as the button clicked.

To get to a more elegant solution than just copy/paste 12 times the code, I wrote the following:

    for i in range (0,12):
        e[i] = Entry(master)
        e[i].insert(0, "<Choose a directory...>")
        e[i].config(width=70)
        e[i].grid(row=i+2, column=0, sticky=NW, columnspan=2)
        b[i] = Button(master, text="Choose directory", command=lambda: self.getDir(e[i]))
        b[i].grid(row=i+2, column=2, sticky=N)

And the callback function:

def getDir(self, e):
    '''Retrieve directory and write it on the right "Entry" widget'''
    dirName = askdirectory(title='Choose a directory:')
    e.delete(0, END)
    e.insert(0, dirName)

When I run the script, I get the "list index out of range" error.

From my understanding, it is because i - which is used later on the code -, is not the index anymore, only in the moment I am building the buttons, right?

So, what should I do to make the callback understand which Button was clicked and to which Entry it should write?

You look like you need to pass an entry to your function rather than an index, but your title says you want to pass an index. Which is it? — Bryan Oakley, Nov 02 '16 at 19:35

score 0 · Answer 1 · answered Nov 02 '16 at 19:01

I can only guess since you didn't post the error message: could simply be the lenght of e and b! e and b need to be lists or tuples with at least the lenght of 12...or if you just want to process your code 12 times you dont need the [i] at all. I would have posted this as a comment but I don't have enough points to do so :(

How do I pass a index of a list to a callback of a button?

1 Answers1