multiple global statements within function elifs

Question

The program first asks the user if they'd like to load their own file or use the the file provided by the script.

filename=0
def first(filename):
    print('Please Select:')
    print('Run Program Now? Press "1"')
    start = int(input('Load Your Own List and Run Program? Press "2": '))

    if start ==1:
        global filename
        filename = 'file.txt'
    elif start ==2:
        import tkinter as tk
        from tkinter import filedialog

        root = tk.Tk()
        root.withdraw()
        global filename
        filename = tkinter.filedialog.askopenfilename()
    else:
        print("You didn't enter a valid selection!")
        first(filename)
    main()

I'm using another function which should call the correct file based on the user input.

def guess(real):
    WORDLIST = filename
    with open(WORDLIST, 'r') as in_file:

Error:

ErrorSyntaxError: name 'filename' is assigned to before global declaration

This all worked earlier when I had the user input and elif statements within

def guess(real):

Although I wanted to call it separately and that's why I have the user input in it's own function.

Sorry, I missed a line of code. (filename=0) I would assume I need a global value to update the main value? that is what I found during research. — CYBORG, Apr 07 '17 at 12:42
No, you should be passing it into the functions that need it. — Daniel Roseman, Apr 07 '17 at 12:43
@DavidG I did try using 'return' but that also didn't work. But should I still need to use a return for a global? shouldn't it return it anyway? — CYBORG, Apr 07 '17 at 12:50

score 1 · Accepted Answer · edited May 23 '17 at 12:10

You don't need to use return with global variables, however I would avoid using global variables if possible. You might want to read "why are global variables evil" for more details.

A simplified version of the code you provided is shown below using return and then passing the result to another function to avoid using global variables:

def first():
    while True:
        print('Please Select:')
        print('Run Program Now? Press "1"')
        start = int(input('Load Your Own List and Run Program? Press "2": '))

        if start == 1:
            filename = 'file.txt'
            return filename
        elif start == 2:
            filename = 'hello.txt'
            return filename
        else:
            print("You didn't enter a valid selection!")

def second(filename):
    print (filename)

filename = first()
second(filename)

multiple global statements within function elifs

1 Answers1