python tkinter中的字典即使使用grid_forget（）也不会在网格中隐藏按钮

Question

EDIT 2: I realized that I forgot to change a variable name at the top to the dictionary... I am very mad now.

EDIT: I changed all these exec's to a dictionary.

First of all, please don't rage at me for using exec()/eval(). It was a last resort, and I'm not taking input for this. brute force writing out variable names seems too lengthy, and I can't think of a better way to do this.

Anyways, I am writing a calendar application in python tkinter, and changing the month has become a problem for me. In a calendar, whenever someone changes a month, the days obviously begin on a different day of the week (May 2014 begins on a Thursday, and June 2014 on a Sunday).

In order to display the days of the month, though, I gave each day a button and its own special variable name using

exec('self.daynum'+str(7*(w-2)+d)+
     ' = Button(text=day, width=2)')

where w and d were variables for the week number and day number. So, when I want to hide these buttons, I believe I should use

exec('self.daynum'+str(day)+'.grid_forget()')

where day is looped over 0-35 and clears the whole grid(in theory). But, instead it raises an AttributeError, insisting that these variables do not exist.

Is there a way to fix this and hide the buttons I don't want, or suggestions on how to remodel the program to not use these (but still hide buttons I don't want)?

Answer 1

There is no good way to fix this fundamentally flawed approach. There is a much simpler approach, which is to use a dictionary to hold your widgets:

widgets = {}
for daynum in range(31):
    widgets[daynum] = Button(text=str(day), width = 2)
...
widgets[daynum].grid_forget()

Doing this will make your code much easier to manage.

Answer 2

Using lists and dicts, you really don't ever need to use eval/exec. The following example creates a calendar of a month and keeps a list of buttons. You can have access to these buttons later using eg dayButtons[0]. So to hide a button later, you can do dayButtons[day].grid_forget().

import Tkinter as tk
import datetime

f = tk.Frame()

dayButtons = []

for day in range(1, 32):
    date = datetime.datetime(day=day, month=5, year=2014)
    _, weeknum, weekday = date.isocalendar()

    dayButton = tk.Button(None, text=str(day), width=2)
    dayButton.grid(row=weeknum, column=weekday)
    dayButtons.append(dayButton)

tk.mainloop()