ValueError：int（）的基数为10的无效文字：''随机数生成器

Question

I'm trying to allow for the button created to randomly generate a value in Tkinter yet i keep getting an error stating

ValueError: invalid literal for int() with base 10: ''

from tkinter import *
from random import *
global playedNumber

class Paul_Lottery:
    def __init__(self):
        self.winningNumber = randrange(1,10)
        self.userInterface = Tk()
        self.playedNumber = 0


        Label(self.userInterface,text ='Type in your name').pack()
        Entry(self.userInterface,width =100).pack()

        Label(self.userInterface,text= 'Enter a number from 1-10:').pack()
        Entry(self.userInterface,width = 100).pack()
        self.justinNumber = Entry(self.userInterface,width=100)


        self.RandomButton= Button(self.userInterface,text = 'Play',command = self.CheckNumber).pack()
        self.finalresult = StringVar()
        self.finalresultLabel=Label(self.userInterface, textvariable = self.finalresult).pack()
        self.userInterface.mainloop()

    def CheckNumber(self):
            playedNumber = int(self.justinNumber.get())

            if playedNumber==self.winningNumber:
                self.finalresult.set('you are a winner')
            else:
                self.finalresult.set('the winning number is' + str(self.winningNumber) + 'you are not a winner')




def main():
     paul_lottery = Paul_Lottery()

main()

I know the string must be converted into a float but confused as to how to do this as i had already set the playedNumber to 0 as an integer.

Answer 1

It looks like you are trying to convert a string to an integer, but the string may contain something that is not convertible to an int. You should handle this by catching the ValueError exception. For example

try:
   playedNumber = int(self.justinNumber.get())
except ValueError as e:
   # Do something reasonable when this error occurs such as
   # 1. Logging an error to help you debug
   # 2. Resetting the widget to a valid state
   # 3. Give the user some feedback (such as a warning message)
   print('Failed to convert to int {}'.format(e))

Answer 2

You are passing an empty string (ie '' ) to your int() method, which is what your error is telling you. It looks to me like you are either pressing your RandomButton without anything entered in the justinNumber field (thus an empty string), or your CheckNumber() method is getting triggered automatically somehow before you are able to enter a guess in your justinNumber field. I think that's where your error is coming from. Note that your CheckNumber() method is still looking in this field for a guess, not checking a random number.

To have the button randomly generate a number, how about you just create a new method, call it random_guess() defined like this:

def random_guess(self):
    guess = np.random.randint(1, 10)
    if guess == self.winningNumber:
        self.finalresult.set('you are a winner')
    else:
        self.finalresult.set('the winning number is' + str(self.winningNumber) + 'you are not a winner')

Then tie that to your random button with:

self.RandomButton = Button(self.userInterface, text='Play',
                           command=self.random_geuss).pack()

And if you want to get fancy, I encourage you to find a way to minimize repeated code before random_guess() and your CheckNumber() on your own!