requested_topping = ["mushrooms","green peppers","extra cheese"]
for requested _topping in requested_toppings:
print("Adding" + "requested_topping + ",")
print("/nFinshed makeing your pozza!")
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Adding mushrooms.
Adding green peppers.
Adding extra cheese.
finished making your pizza!
#如果披萨店的青椒用完了如何处理
for requested _topping in requested_toppings:
if requested_topping == "green peppers":
print("Sorry,we are out of green peppers right now.")
else:
pprint("Adding " + requested_topping +".")
print("/nFinished making your pizza!")
---------------------------------------------------------------------------------------------------------------------------------
Adding mushrooms.
Sorry,we are out of green peppers right now.
Adding extra cheese.
Finshed making your pizza!
- Q：确定列表不是空的
- A：if +列表名 检查是否为空列表
requested_ toppings = []
if requested_ toppings:
for requested. _topping in requested_ _toppings:
print("Adding” + requested_ topping +.")
print("
Finished making your pizza!")
else:
print("Are you sure you want a plain pizza?")
#在if列表中将列表名用在条件表达式中，python将在列表至少包含一个元素时返回Ture，并在列表为空时返回False。
available_ toppings = ['mushrooms', 'olives', 'green peppers'，' pepperoni',' pineapple', 'extra cheese']
requested_ toppings = ['mushrooms','french fries','extra cheese']
for requested topping in requested toppings:
if requested topping in available_ toppings:
print("Adding " + requested_ topping + ".")
else:
print("Sorry, we don't have " + requested_ topping + ".")
print("/nFinshed making your pozza!")