为什么会出现错误：“ NameError：未定义全局名称'pupiluserinputbox'”

Question

def pupiluserpass():
    global usernames, passwords
    usernameinp = pupiluserinputbox.get()
    passwordinp = pupilpasswordinputbox.get()

Why do I get the error: NameError: global name 'pupiluserinputbox' is not defined?

The input boxes are in another procedure:

def pupillogin():
   ruapupil = Label(app, text = "If you're a pupil log in here:")
   ruapupil.grid(row = 1, columnspan = 3, sticky = W)

   pupilusername = Label(app, text = "Please enter your Username:")
   pupilusername.grid(row = 2, column = 0, sticky = W)
   pupiluserinputbox = Entry(app, width = 10)
   pupiluserinputbox.grid(row = 2, column = 1, sticky = W)

   pupilpassword = Label(app, text = "Please enter your Password:")
   pupilpassword.grid(row = 3, column = 0, sticky = W)
   pupilpasswordinputbox = Entry(app, width = 10)
   pupilpasswordinputbox.grid(row = 3, column = 1, sticky = W)

   pupilenter = Button(app, text = "Enter!", command = pupiluserpass)
   pupilenter.config(height = 1, width = 8)
   pupilenter.grid(row = 4, column = 1, sticky = W) 

How can I make this work successfully and not get a NameError ?

Answer 1

For a class , you should make the variables that carry those errors attributes to self , ie the current instance of that object. This is the de facto way to access these variables in other methods within the class . For example:

def pupiluserpass():
    ...
    usernameinp = self.pupiluserinbox.get()
    passwordinp = self.pupilpasswordinputbox.get()

def pupillogin():
    ...
    self.pupiluserinputbox = Entry(app, width = 10)
    self.pupiluserinputbox.grid(row = 2, column = 1, sticky = W)
    ...
    self.pupilpasswordinputbox = Entry(app, width = 10)
    self.pupilpasswordinputbox.grid(row = 3, column = 1, sticky = W)

You could also do lots of global declarations here instead but it is better to use self .