我正在编写一个简单的文字游戏来增强我对 Python 的了解。在游戏的某个阶段，用户需要猜出集合[1, 5]中的一个数字才能实现自己的愿望。他们只有三次尝试机会。我有两个问题：
1、假设 genie_number 随机选为 3。这个值在用户每次猜测后是否会改变？我不想让程序在每次猜测后随机选择另一个整数。它应该保持不变，这样用户就有 3/5 的机会猜对。
2、我希望对那些不只猜测整数的用户进行惩罚，我已经在 except ValueError 部分完成这一点。但是，如果用户连续三次猜测非整数并用尽所有尝试机会，我希望循环重定向到 else：dead("The genie turns you into a frog."). 现在它给了我下面的错误信息。我该如何解决这个问题？
'Before I grant your first wish,' says the genie, 'you must answer this
'I am thinking of a discrete integer contained in the set [1, 5]. You ha
(That isn't much of a riddle, but you'd better do what he says.)
What is your guess? > what
That is not an option. Tries remaining: 2
What is your guess? > what
That is not an option. Tries remaining: 1
What is your guess? > what
That is not an option. Tries remaining: 0
Traceback (most recent call last):
File "ex36.py", line 76, in <module>
start()
File "ex36.py", line 68, in start
lamp()
File "ex36.py", line 48, in lamp
rub()
File "ex36.py", line 38, in rub
wish_1_riddle()
File "ex36.py", line 30, in wish_1_riddle
if guess == genie_number:
UnboundLocalError: local variable 'guess' referenced before assignment
以下是我的部分代码：
def wish_1_riddle():
print "\n'Before I grant your first wish,' says the genie, 'you must answer this riddle!'"
print "'I am thinking of a discrete integer contained in the set [1, 5]. You have three tries.'"
print "(That isn't much of a riddle, but you'd better do what he says.)"
genie_number = randint(1, 5)
tries = 0
tries_remaining = 3
while tries < 3:
try:
guess = int(raw_input("What is your guess? > "))
tries += 1
tries_remaining -= 1
if guess == genie_number:
print "Correct!"
wish_1_grant()
else:
print "Incorrect! Tries remaining: %d" % tries_remaining
continue
except ValueError:
tries += 1
tries_remaining -= 1
print "That is not an option. The genie penalizes you a try. Be careful!"
print "Tries remaining: %d" % tries_remaining
if guess == genie_number:
wish_1_grant()
else:
dead("The genie turns you into a frog.")
解决方案
问题 1 的解答：
不，不会改变。如果您不断调用 randint(1, 5)，是的，它会改变，但一旦您分配它，该值就固定了：
>>> import random
>>> x = random.randint(1, 10)
>>> x
8
>>> x
8
>>> x
8
>>> random.randint(1, 10)
4
>>> random.randint(1, 10)
8
>>> random.randint(1, 10)
10
如您所见，一旦我们将随机数分配给 x，x 始终保持不变。但是，如果我们继续调用 randint()，它就会改变。
问题 2 的解答：
在 int(raw_input()) 之后，您不应该让 tries 加 1，如果该值是一个整数，它也会把 tries 加 1。相反，尝试将您的代码合并到类似以下的内容中：
tries = 0
while tries < 3:
try:
x = raw_input('Hello: ')
x = int(x)
except ValueError:
tries+=1
您收到错误，因为您已经错误地回答了所有 3 次问题。因此，没有为 guess 分配任何值。在 while 循环之后，您尝试查看 guess 是否为某个值，而它不是：
tries = 0
while tries < 3:
try:
guess = int(raw_input('Enter input: '))
print guess
except ValueError:
tries+=1
完整代码如下：
def wish_1_riddle():
print "\n'Before I grant your first wish,' says the genie, 'you must answer this riddle!'"
print "'I am thinking of a discrete integer contained in the set [1, 5]. You have three tries.'"
print "(That isn't much of a riddle, but you'd better do what he says.)"
genie_number = randint(1, 5)
tries = 0
tries_remaining = 3
while tries < 3:
try:
guess = int(raw_input("What is your guess? > "))
tries += 1
tries_remaining -= 1
if guess == genie_number:
print "Correct!"
wish_1_grant()
else:
print "Incorrect! Tries remaining: %d" % tries_remaining
except ValueError:
tries += 1
tries_remaining -= 1
print "That is not an option. The genie penalizes you a try. Be careful!"
print "Tries remaining: %d" % tries_remaining
if guess == genie_number:
wish_1_grant()
else:
dead("The genie turns you into a frog.")
