<p>我希望用户能够退出这个程序在任何时候输入“退出”。在</p>
<p>有没有一种方法可以用break语句的一个实例来实现这一点,还是需要在代码中的每个“if y==”语句中添加一个break?在</p>
<pre><code>fruits = []
notfruits = []
print(fruits)
print(notfruits)
while len(fruits) < 3 or len(notfruits) < 3: # replaced `and` with `or`
print("Please enter fruits or notfruits:") #
y = str(input(": ")) # moved the input here
if y == "fruits":
while len(fruits) < 3:
x = str(input(": "))
x = x.strip()
if x in notfruits:
print(x + " is not a fruit!")
elif x in fruits:
print(x + " is already in the list!")
else:
fruits.<a href="https://www.cnpython.com/list/append" class="inner-link">append</a>(x)
print(fruits)
elif y == "notfruits":
while len(notfruits) < 3:
x = str(input(": "))
x = x.strip()
if x in fruits:
print(x + " is a fruit!")
elif x in notfruits:
print(x + " is already in the list!")
else:
notfruits.append(x)
print(notfruits)
elif y == "clearfruits":
del fruits[:]
elif y == "clearnotfruits":
del notfruits[:]
elif y == "quit":
break
else:
print("Not a valid option!")
</code></pre>