use a variable defined in a function outside the function-CodePudding

I have this function here.

def choose_file():
    file = askopenfile(mode ='r', filetypes =[('xodr Files', '*.xodr')])
    if file:
        res = "selected:", file
    else:
        res = "file not selected"
    return(res)

I have this button to open the dialog and choose a file

e3=Button (scalF, text='Wählen Sie ein Dokument',font=('Bahnschrift SemiLight',12),command=choose_file, bg='blue')
e3.pack(side='top')

after choosing a file and closing the dialog I want to display the value of the variable defined res in the choose_file() in the label below

chosenFile = Label(scalF,text="I want to write here",font=('Bahnschrift SemiLight', 10))
chosenFile.pack(side='top')

can you explain how to read the variable resfrom the global scope?

CodePudding user response：

You can use tk.StringVar to hold the strings variables.

file_result = tk.StringVar()

def choose_file():
    file = askopenfile(mode ='r', filetypes =[('xodr Files', '*.xodr')])
    if file:
        res = "selected: {0}".format(file.name)
    else:
        res = "file not selected"
    file_result.set(res)

Then this variable(file_result) can be passed to Labels textvariable argument(Whose value will be used in place of the text).

chosenFile = Label(scalF, font=('Bahnschrift SemiLight', 10), textvariable=file_result)

CodePudding user response：

one of the ways i can recommend is : add global res to the 1st line of ur function.

CodePudding user response：

You can use the variable in the global scope by declaring it using the global keyword.

def choose_file():
    global res
    file = askopenfile(mode ='r', filetypes =[('xodr Files', '*.xodr')])
    if file:
        res = "selected:", file
    else:
        res = "file not selected"
    return(res)

If you wanna explore more, you can learn about namespaces in python

CodePudding user response：

You could use a class:

class File():
    def __init__(self):
        self.res = None

        e3=Button (scalF, text='Wählen Sie ein Dokument', font=('Bahnschrift SemiLight',12), command=self.choose_file, bg='blue')
        e3.pack(side='top')

    def choose_file(self):
        # Your implementation but updating self.res, without return

    def get_res(self):
        return self.res