全局名称错误

Question

我对Python还很陌生，所以如果我的问题微不足道甚至很愚蠢，我很抱歉。我试图建立一个小模块，对一个按钮的回调反应(这不是在代码中)。回调在main()函数中模拟。现在我的问题是，我不知道如何摆脱全局名称错误。它说drink0_ingred没有被定义为全局名称。我需要这个作为self。10标签的文本。这是我目前所看到的:

import tkinter
from tkinter import ttk

def main():
    root = tkinter.Tk()
    callback = callbackkb0()
    drink0 = Drink0(root)
    root.mainloop()

def callbackkb0():
    with open(file="drink0_ingred.txt") as ingred0:
        drink0_ingred = ingred0.read()
    print(drink0_ingred)
    return drink0_ingred

class Drink0(ttk.Frame):
    def __init__(self, root):
        ttk.Frame.__init__(self, root)
        self.grid()
        self.widgets_create()
    def widgets_create(self):
        self.l0 = ttk.Label(self, text=drink0_ingred)
        self.l0.grid()

main()

我如何定义drink0_ingred作为全局名称，并使其可访问其他函数?谢谢你的帮助!

Answer 1

你可以做两件事:

全球化drink0_ingred:

with open(file="drink0_ingred.txt") as ingred0:
    global drink0_ingred
    drink0_ingred = ingred0.read()

调用函数而不是调用变量:

self.l0 = ttk.Label(self, text=callbackkb0()) # Notice how I called the function 
                                              # because it returned drink0_ingred