python - python为什么显示 'list index out of range'错误？

Question

我是python的新手，仅在1周前开始学习。该程序非常有效，除了当我在以0开头的guess1变量中输入数字时。

import random
import sys
def script():
    while True:
        number1 = random.randint(1000, 9999)
        number1 = int(number1)
        while True:
            print ("Enter Your Guess")
            guess1 = input()
            guess1 = int(guess1)
            while True:
                if guess1 != number1:
                    break
                elif guess1 == number1:
                    print ("Your Guess Was Right!")
                    print ("Do you want to play again? Type YES or NO")
                    ask = input()
                    ask = str(ask)
                    if ask == "YES" or ask == "yes":
                        script()
                    elif ask == "NO" or ask == "no":
                        sys.exit()
                    else:
                        print ("Invalid input, try again.")
                        continue
            number = list(str(number1))
            guess = list(str(guess1))
            if len(guess) > 4:
                print ("Please type a 4-digit number")
                continue
            bulls = 0
            wr = 0
            cows = 0
            a = 3
            while a >= 0:
                if number[a] == guess[a]:
                    number[a] = 'a'
                    guess[a] = 'b'
                    bulls += 1
                a -= 1
            b = 0
            c = 0
            while b < 4:
                c = 0
                while c < 4:
                    if number[b] == guess[c]:
                        number[b] = 'a'
                        guess[c] = 'b'
                        wr += 1
                    c += 1
                b += 1
            z = bulls + wr
            cows = 4 - z
            bulls = str(bulls)
            cows = str(cows)
            wr = str(wr)
            print ("Cows: "+cows)
            print ("Bulls: "+bulls)
            print ("Wrongly Placed: "+wr)
        break
script()

这是一个为游戏编写的程序，其中要猜测一个4位数字。我们从一个随机数开始，然后以奶牛，公牛和放错位置的形式获得线索。牛表示数字错误，公牛表示数字正确，放错位置表示数字正确但放错位置。
整个过程正常工作，但是当我输入一个以0开头的数字时，它显示如下内容:-

Traceback (most recent call last):
  File "GuessingGame.py", line 61, in <module>
    script()
  File "GuessingGame.py", line 36, in script
    if number[a] == guess[a]:
IndexError: list index out of range

请帮忙，谢谢!

更新:

感谢用户@blue_note的回答，该程序现在可以运行!这就是它的修改方式-

import random
import sys
def script():
    while True:
        number1 = random.randint(1000, 9999)
        number1 = int(number1)
        while True:
            print ("Enter Your Guess")
            guess1 = input()
            number = list(str(number1))
            guess = list(str(guess1))
            if guess[0] == 0:
                guess1 = str(guess1)
            else:
                guess1 = int(guess1)
            while True:
                if guess1 != number1:
                    break
                elif guess1 == number1:
                    print ("Your Guess Was Right!")
                    print ("Do you want to play again? Type YES or NO")
                    ask = input()
                    ask = str(ask)
                    if ask == "YES" or ask == "yes":
                        script()
                    elif ask == "NO" or ask == "no":
                        sys.exit()
                    else:
                        print ("Invalid input, try again.")
                        continue
            bulls = 0
            wr = 0
            cows = 0
            a = 3
            while a >= 0:
                if number[a] == guess[a]:
                    number[a] = 'a'
                    guess[a] = 'b'
                    bulls += 1
                a -= 1
            b = 0
            c = 0
            while b < 4:
                c = 0
                while c < 4:
                    if number[b] == guess[c]:
                        number[b] = 'a'
                        guess[c] = 'b'
                        wr += 1
                    c += 1
                b += 1
            z = bulls + wr
            cows = 4 - z
            bulls = str(bulls)
            cows = str(cows)
            wr = str(wr)
            print ("Cows: "+cows)
            print ("Bulls: "+bulls)
            print ("Wrongly Placed: "+wr)
        break
script()

由于我的猜测总是错误的，如果第一个数字为0，则无需将其转换为int。

再次感谢您的帮助!这是我在网站上的第一个问题。这确实是一个很酷的网站。

Answer 1

当您传递以0开头的整数(例如0123)，并在下一行将其转换为int时，剩下的是123(3位数字)。稍后，您执行number = list(str(number1))，因此您的number是['1', '2', '3'](长度3)。然后，尝试使用number[a]获取a=3，那就是您得到了错误。

你可以做类似的事情

number = list(str(number1) if number1 > 999 else '0' + str(number1))