pizza = str(input('Which size pizza do you want: S/M/L/XL?'))
while pizza != "S/M/L/XL":
print(" That is not a valid answer")
pizza = "S/M/L/XL"
pizza = str(input("Which size pizza do you want: S/M/L/XL?"))
这就是我所拥有的，但它的剂量工作
pizza = str(input('Which size pizza do you want: S/M/L/XL?'))
while pizza != "S" and pizza != "M" and pizza!="L" and pizza!="XL"and pizza!="s"and pizza!="m"and pizza!="l"and pizza!="xl":
print(" That is not a valid answer")
pizza = str(input("Which size pizza do you want: S/M/L/XL?"))
print(pizza.upper())
这就是你想要的吗？
将允许的字符列表设置为一个集合，并检查输入是否在该集合中。此外，强制输入大写字符，这样用户就不必担心了
此外，输入中有str是多余的，默认情况下input会返回一个字符串。
pizza = input('Which size pizza do you want: S/M/L/XL?').upper()
while pizza not in ('S','M','L','XL'):
print(" That is not a valid answer")
pizza = input("Which size pizza do you want: S/M/L/XL?").upper()
试试这个。我为一个函数编写了代码。
def asking():
pizza = str(input('Which size pizza do you want: S/M/L/XL? ')).upper()
if pizza != 'S' and pizza != 'M' and pizza != 'L' and pizza != 'XL':
print('That is not a valid answer!')
asking()
else:
print('Okay, your pizza's size will be: {}'.format(pizza))
asking()
我建议您不要重复使用变量名。它将帮助你真正"命名"事物。"pizza"是变量的最佳名称吗？"大小"或"订单"如何？这将帮助您更容易地发现错误。让我们重命名这些变量。
size_of_pizza = str(input('Which size pizza do you want: S/M/L/XL?'))
while size_of_pizza != "S/M/L/XL":
print(" That is not a valid answer")
pizza = "S/M/L/XL" # See? Here you're manipulating the value of 'pizza' inside a 'while' loop. That's not advised, you can remove this line
size_of_pizza = str(input("Which size pizza do you want: S/M/L/XL?"))
让我们去掉那条线。我们最终得到：
size_of_pizza = str(input('Which size pizza do you want: S/M/L/XL?'))
while size_of_pizza != "S/M/L/XL":
print(" That is not a valid answer")
size_of_pizza = str(input("Which size pizza do you want: S/M/L/XL?"))
哦，但请注意，你在问披萨的尺寸"S/M/L/XL"；。这是不对的！你有几个正确的答案，所以你要么需要几个if子句，要么需要某种类型的列表或迭代器。这个怎么样。。。
size_of_pizza = str(input('Which size pizza do you want: S/M/L/XL?'))
while size_of_pizza not in ["S","M","L","XL"]:
print("That is not a valid answer")
size_of_pizza = str(input("Which size pizza do you want: S/M/L/XL?"))
好多了！但是你还有工作要做！让我问你：
- 如果用户输入一个数字会发生什么(你可能已经想到了，但你应该知道这个决定！(
- size_of_pizza应该总是被强制变成字符串吗
祝你好运！