python tkinter在按键上书写标签

Question

 def button_pressed(item_name, item_price):
    global lbl
    for v1, v2 in zip(item_name, item_price):
        item_values = '{} {}'.format(v1, v2)
        sv = StringVar()
        lbl = Label(shop_window, height="2", textvariable=sv, anchor = NW).grid(columnspan = 4)
        sv.set(item_values)

# Create initial shopping cart window

shop_window = Tk()
shop_window.title('Welcome to the Outlet')
shop_window.geometry("1200x900")
shop_window.resizable(0, 0)


introduction_text = Label(shop_window, text = 'Welcome to the Shopping Outlet', font = ('Arial', 30))

electronics_button = Button(shop_window, text = 'Buy Electronics', font = ('Arial', 18), command = lambda:button_pressed(electronics_name, electronics_price))
books_button = Button(shop_window, text = 'Buy Books', font = ('Arial', 18), command = lambda:button_pressed(books_name, books_price))
kitchen_button = Button(shop_window, text = 'Buy Kitchen', font = ('Arial', 18), command = lambda:button_pressed(kitchen_name, kitchen_price))
monitors_button = Button(shop_window, text = 'Buy Kitchen', font = ('Arial', 18), command = lambda:button_pressed(monitors_name, monitors_price))

introduction_text.grid(row = 0, column = 0, columnspan = 4, sticky = N )

electronics_button.grid(row = 2, column = 0)
books_button.grid(row = 2, column = 1)
kitchen_button.grid(row = 2, column =2)
monitors_button.grid(row = 2, column = 3)

我创建了这个tk窗口来显示每个类别10个项目的购物列表。每个类别都有两个列表，item_name/item_price（它们是从amazon上删除的）

当我运行程序时，我可以按下按钮，列表将正确显示，但如果我再按一次，它会在先前制作的标签末尾添加新标签。例如，我的问题是如何使程序覆盖以前的标签。但“购买我的电子产品”后添加了更多的标签。我想把“买电子产品”的标签写多了。我想这可能是某种global lbl，但不确定。在

Answer 1

你可以为标签创建一个框架

f = Frame(shop_window)
f.grid(row=3, column=0, columnspan=4)

然后在回调函数中销毁框架的所有子级并创建新的子级

^{pr2}$

Answer 2

请参阅函数已创建的示例上的，要做到这一点，您需要在使用lbl["text"] = sv在那里定位当前的一个之前覆盖它

def button_pressed(item_name, item_price):
    global lbl
    for v1, v2 in zip(item_name, item_price):
        item_values = '{} {}'.format(v1, v2)
       # sv = StringVar()
        lbl["text"] = sv
        sv.set(item_values)

然后在root和{}内创建Label

^{pr2}$