Question

我正在处理以下程序，我无法从displayPage类中的搜索方法访问数据（它是一个数据帧）对象。我尝试使用全局关键字。似乎没有用，任何人都可以帮我解决这个问题吗？

import tkinter as tk
import tkinter.messagebox as tm
from tkinter import *
from tkinter import ttk
import sys
import pandas as pd

global data

#importing our other .py file whihc is used for scraping infomration from the webpages
import scrape

FONTT = ("Times", "12", "bold italic")

class myApp(tk.Tk): 
    def __init__(self,*args,**kwargs):
        tk.Tk.__init__(self,*args,**kwargs)

        tk.Tk.wm_title(self,"Python Project")
        container = tk.Frame(self)
        container.pack(side = "top", fill = "both", expand = True)
        container.grid_rowconfigure(0,weight = 1)
        container.grid_columnconfigure(0,weight = 1)

        self.frames = {}
        for F in (LoginPage, SearchPage,displayPage):
            frame = F(container,self)
            self.frames[F] = frame
            frame.grid(row = 0,column = 0,sticky = "nsew")

        self.show_frame(LoginPage)

    #Function to show the page required thorugh navigation in the application
    def show_frame(self,cont):
        frame = self.frames[cont]
        frame.tkraise()    


#Function to validate the username and password entered by the user

def loginValidate(user,pwd,cont):
    if(user == "yogesh" and pwd == "123456"):
        cont.show_frame(SearchPage)
    else:
        tm.showerror("Login error", "Incorrect username or password")

#Function for fetching the dataframe containing the scraped infomration
def search(item,loc,cont):
    **data = scrape.scrape_info(item,loc)**
    cont.show_frame(displayPage)

class LoginPage(tk.Frame):

    def __init__(self,parent,controller):
        tk.Frame.__init__(self,parent)
        usr_login = StringVar()
        pwd_login = StringVar()
        userLabel = tk.Label(self,text = "Name",font = FONTT )
        passwordLabel = tk.Label(self,text = "Password", font = FONTT)

        userEntry = tk.Entry(self, textvariable = usr_login, bd=5)
        passwordEntry = tk.Entry(self, textvariable=pwd_login,bd=5,show = "*")

        submitButton = ttk.Button(self,text = "Login",command = lambda: loginValidate(usr_login.get(),pwd_login.get(),controller))
        quitButton = ttk.Button(self,text = "Quit",command = self.exit)


        userLabel.grid(row = 0,sticky = "E",padx =10,pady =10)
        passwordLabel.grid(row =1,sticky = "E",padx =10,pady =10)
        userEntry.grid(row=0,column=1,padx =10,pady =10)
        passwordEntry.grid(row=1,column=1,padx =10,pady =10)
        submitButton.grid(row =2,column =1,padx =10,pady =10)
        quitButton.grid(row=2,column=2,padx =10,pady =10)

    def exit(self):
        exit()

class SearchPage(tk.Frame):
    def __init__(self,parent,controller):
        tk.Frame.__init__(self,parent)
        welcomeLabel = tk.Label(self,text = "Welcome User", font = FONTT)
        logoutButton = ttk.Button(self,text = "Logout", command = lambda: controller.show_frame(LoginPage))

        item_search = StringVar()
        loc_search = StringVar()        

        item = tk.Label(self,text = "Find?")
        location = tk.Label(self,text = "Location?")
        itemSearch = tk.Entry(self,bd =5,textvariable = item_search)
        locSearch = tk.Entry(self,bd =5,textvariable = loc_search)

        searchButton = ttk.Button(self,text = "Search",command = lambda: search(item_search.get(),loc_search.get(),controller) )

        welcomeLabel.grid(row = 0)
        logoutButton.grid(row = 0,column =2)



        item.grid(row=1,column=0,padx =10,pady =10)
        location.grid(row=2,column=0,padx =10,pady =10)
        itemSearch.grid(row=1,column=1,padx =10,pady =10)
        locSearch.grid(row=2,column=1,padx =10,pady =10)
        searchButton.grid(row=3,column=1,padx =10,pady =10)

class displayPage(tk.Frame):
    def __init__(self,parent,controller):
        tk.Frame.__init__(self,parent)
        for i in range(25):
            **lable = tk.Label(self,text = str(data.business_name[i]),padx =10,pady =10 )**
            lable.pack()


app = myApp()
app.mainloop()

Answer 1

您应该将global data移到data = scrape.scrape_info(item,loc)上方的行，因为没有它，分配会在data的范围内创建一个新的displayPage变量__init__方法。

见这个非常基本的例子：

def foo():
    global a
    a = 1

def bar():
    print(a)

foo()
bar()
>> 1

如果我们从global a删除foo，即

def foo():
    a = 1

def bar():
    print(a)

foo()
bar()
>> Traceback (most recent call last):
   File "main.py", line 33, in <module>
       ba()
   File "main.py", line 30, in bar
       print(a)
   NameError: name 'a' is not defined

Answer 2

您需要在global方法中使用search关键字来访问全局data。

def search(item,loc,cont):
    global data

使数据帧全局化，以便我可以在类中的任何位置访问它

2 个答案: