Python Tkinter saving a list

Question

Help, I'm trying to save all the data in my file as a list.

register = []


def some_command():
    register.append([variable,'variable_x'])

def save():
    outFile = open('Save.txt', 'wb')
    pickle.dump(register, outFile)
    outFile.close()

It saves the file succesfully. But when I use "some_command" to add a new element to "register" it doesn't update; It doesn't even give an error. What could be the problem?

just checking it's not an indenting problem, so in the actual source you have the register.append... line tabbed in? — max k., Mar 09 '13 at 06:22
Can you give a more complete example showing what `variable` is when you are using `some_command`? — Radio-, Mar 09 '13 at 06:24
There are several not just one. For example: [Yellow,'Color'] [True, 'Is Monty Python funny?'] [42, 'Meaning of Life'] — madprogramer, Mar 09 '13 at 06:27

score 1 · Accepted Answer · answered Mar 09 '13 at 06:28

1

It will work if you pass register and variable into some_command, but otherwise you cant edit register properly from inside the function. So, it would look something like this:

def some_command( register, variable ):
    register.append([variable,'variable_x'])

It's not strictly necessary to pass variable in, but it does help keep things neat.

And obviously you would call it with

some_command( register, whatever you want )

answered Mar 09 '13 at 06:28

max k.

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Can't I: def some_command(): global register ... instead? – madprogramer Mar 09 '13 at 06:30
Have you tried it? I know the method that I put up is recommended to keep things neat when the projects get large (and people just generally hate global), but if that worked it would definitely be a better fix, and a lot smaller too – max k. Mar 09 '13 at 06:32
Tried, but it doesn't work. The problem with your code is that this saving function is supposed to be automatic. So just passing in some_command() should be enough. – madprogramer Mar 09 '13 at 06:41
Not sure what you mean by supposed to be automatic, so just some_command() should be enough? As in it is a callback or something like that? If that's the problem, you can always use a lambda to call it – max k. Mar 09 '13 at 06:44
http://stackoverflow.com/questions/423379/using-global-variables-in-a-function-other-than-the-one-that-created-them You can implement the register-variable as global, but as said above, global variables are mostly frowned upon (for a good reason). – Sami N Mar 09 '13 at 09:10
@madprogramer If you desperately wanted to use globals: `global register; register = []` (using semicolons so that you can see the separation; hard to show multiple lines of code in a comment. `def some_command(): register.append([variable, 'variable_x'])` You need it to be declared as `global` when you define the variable. – Rushy Panchal Mar 09 '13 at 16:48

Python Tkinter saving a list

1 Answers1