字符串索引错误解决方案

字符串索引错误通常是由于尝试访问字符串中不存在的索引位置而引起的。我在Python编译中，字符串是一个不可变的序列，可以通过索引访问其中的字符。如果尝试访问超出字符串长度范围的索引位置，将引发IndexError异常。所以下面的问题如果遇到了，可以这样解决。

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1、问题背景

Tom和Alice合作开发了一个名为Hangman的文字游戏作为项目作业。HangmanGUI是一个图形界面，可让用户进行互动体验。在运行HangmanGUI时，他们遇到如下错误：

 self.__letterVar.set(self.__ans.getAnswer())
 TypeError: set() missing 1 required positional argument: 'value'

2、解决方案

为了解决 TypeError: set() missing 1 required positional argument 的错误，需要在 HangmanGUI 类中将 self.__letterVar 变量声明为 StringVar 的实例。

将 self.__letterVar= StringVar 替换为 self.__letterVar = StringVar()

修改后的代码如下：

from tkinter import *
from random import *
from hangman import *

FOUR = 4

class HangmanUI(Frame):

  def __init__(self):
    Frame.__init__(self)
    self.master.title("Hangman")
    self.grid()
    self.__label = Label(self, text = "Let's play Hangman!")
    self.__label2 = Label(self, text = "Please choose a category!")
    self.__label2.grid(row = 1, column = 0)
    self.__buttonPane = Frame(self)
    self.__buttonPane.grid(row = 2, column = 0)
    # 创建了一个 Hangman 类的模型
    self.__ans = Hangman()
    self.__fruitButton= Button(self.__buttonPane, text = 'Fruits', command = self.startFruit)
    self.__nameButton = Button(self.__buttonPane, text = 'Names' , command = self.startName)
    self.__vegeButton = Button(self.__buttonPane, text = 'Veges', command = self.startVege)
    self.__fruitButton.grid(row = 2, column = 0)
    self.__vegeButton.grid(row = 2, column = 1)
    self.__nameButton.grid(row = 2, column = 2)
    self.__label.grid(row = 0 , column = 0)
    # to change later so if shuffles images 1-10 with each error (for loop)
    self.__image = PhotoImage(file = "0.gif")
    self.__imageLabel = Label(self, image = self.__image)
    self.__imageLabel.grid(row = 3, column = 0)
    self.__letterLabel = Label(self, text = "Please submit a letter to play!")
    # instead of the submit button, tried using enter instead for now
    self.__letterVar = StringVar()
    self.__letterEntry = Entry(self, textvariable = self.__letterVar)
    self.__letterEntry.bind('<Return>', self.set)
    self.__letterLabel.grid(row = 4, column = 0)
    self.__letterEntry.grid(row = 5, column = 0)

    self.__value = Label(self, textvariable = self.__letterVar)
    self.__value.grid(row= 6, column = 0)


    # creates nested frame
    self.__letterPane = Frame(self)
    self.__letterPane.grid(row = 7, column = 0)
    self.__letter1 = Label(self.__letterPane, text = '_  _  _  _  _  _')
    self.__letter1.grid(row = 7, column = 0)

  def startFruit(self):
    self.__ans.startFruit()

  def startVege(self):
    self.__ans.startVege()

  def startName(self):
    self.__ans.startName()

  def set(self,event):
    guessWord = self.__ans.getTheWord()
    entryLetter = self.__letterEntry.get()
    self.__ans.find(guessWord, entryLetter)
    newValue = self.__letterEntry.get()
    self.__ans.set(newValue)
    # display new value in letterVar
    # this is where the program crashes
    self.__letterVar.set(self.__ans.getAnswer())
    # invoke delete() to clear entry box
    self.__letterEntry.delete(0,END)


def main():
  HangmanUI().mainloop()

main()