我需要帮助在一个简单的随机数游戏中修复 ValueError

Question

我创建了一个简单的数字猜谜游戏，我正在尝试修复一个意外输入任何内容的错误。

当程序要求猜测时，如果用户在没有输入数字的情况下点击回车，则会出现以下错误：

Traceback（最近一次调用最后一次）：文件 “/Users/tom/Documents/Automate with Python/RandomNumberGame.py”，行 13、在 guess = int(input()) ValueError: int() 以 10 为底的无效文字：''

我希望它改为打印“请输入一个数字”。

我是编程新手，已开始阅读“使用 Python 自动化无聊的东西”。提前致谢！

原代码没有包含

elif guess == ' ':
     print('Please enter a number')

但目标是让程序说如果输入为空

我尝试添加：

guess = int(input()) or str(input()) 

没有任何进展

猜数字游戏

import random
print('Hello, What is your name?')
name = input()
print('Well, ' + name + ', I am thinking of a number between 1 and 1000, You have 10 guesses to figure it out. Good luck!')
secretNumber = random.randint(1,1000)

print('DEBUG: Secret number is ' + str(secretNumber))

for guessesTaken in range(1,11):
    print('Take a guess.')
    guess = int(input())


    if guess < secretNumber: 
          print('Your guess is too low.')
    elif guess > secretNumber:
          print('Your guess is too high.')
    elif guess == ' ':
          print('Please enter a number')
    else:
          break #This condition is for the correct guess

if guess == secretNumber:
          print('Good job ' + name + '! You guessed the number in ' + str(guessesTaken) + ' guesses!')
else:
          print('Too many guesses, The number I was thinking of was ' + str(secretNumber))

Answer 1

变量guess 是一个整数值，因为您将输入转换为整数：guess = int(input())。如果输入是空格或任何其他无效字符串（无法解析为数字），则会引发 ValueError exception - 这就是您收到该错误消息的原因。

您可以使用 try/except 块在 Python 中发生特定异常时进行处理。它是这样工作的：

try:
  # execute some code
except SomeException:
  # handle the exception

try 块中的代码将尝试执行，如果运行代码导致引发异常 SomeException，则将运行 except 块中的代码。

在您的特定情况下，您要做的是处理 ValueError 异常，因此您可以像这样将相关代码包装在 try/except 中：

...
for guessesTaken in range(1,11):
    print('Take a guess.')

    try:
        guess = int(input())
        if guess < secretNumber: 
              print('Your guess is too low.')
        elif guess > secretNumber:
              print('Your guess is too high.')
        elif guess == ' ':
              print('Please enter a number')
        else:
              break #This condition is for the correct guess
    except ValueError:
        print('Please enter a number')
...

如果您希望无效输入不进行猜测，您可以像这样实现游戏：

...
guessesTaken = 1
while True:
    print('Take a guess.')

    try:
        guess = int(input())
        if guess < secretNumber: 
              print('Your guess is too low.')
        elif guess > secretNumber:
              print('Your guess is too high.')
        elif guess == ' ':
              print('Please enter a number')
        else:
              break #This condition is for the correct guess
    except ValueError:
        print('Please enter a number')
        continue # go back to the start of loop (without incrementing guessesTaken)

    guessesTaken += 1
    if guessesTaken >= 10:
        break
...

Answer 2

如果您也不想在用户没有输入数字就按 Enter 键的情况下输掉一次尝试。您可以像这样在 while True: 块中使用 try-except

#code till this
for guessesTaken in range(1,11):
    print('Take a guess.')
    while True:
        try:
            guess = int(input())
            break
        except ValueError:
            print('Please enter a number')
            continue
#rest of your code

这将允许用户在尝试次数保持不变的情况下意外按 Enter 继续游戏。

完整代码：

import random
print('Hello, What is your name?')
name = input()
print('Well, ' + name + ', I am thinking of a number between 1 and 1000, You have 10 guesses to figure it out. Good luck!')
secretNumber = random.randint(1,1000)

print('DEBUG: Secret number is ' + str(secretNumber))

#code till this
for guessesTaken in range(1,11):
    print('Take a guess.')
    while True:
        try:
            guess = int(input())
            break
        except ValueError:
            print('Please enter a number')
            continue
#rest of your code

    if guess < secretNumber:
          print('Your guess is too low.')
    elif guess > secretNumber:
          print('Your guess is too high.')
    else:
          break #This condition is for the correct guess

if guess == secretNumber:
          print('Good job ' + name + '! You guessed the number in ' + str(guessesTaken) + ' guesses!')
else:
          print('Too many guesses, The number I was thinking of was ' + str(secretNumber))