Python编程 从入门到实践-5if语句下

笔记出处(学习UP主视频记录) https://www.bilibili.com/video/av35698354?p=10

5.4.1 检查特殊元素

requested_toppings = ['mushrooms', 'green peppers', 'extra chees']

for requested_topping in requested_toppings:
    print ("Adding " + requested_topping + ".")

print ("
Finished making your pizza!")

Adding mushrooms.
Adding green peppers.
Adding extra chees.

Finished making your pizza!

requested_toppings = ['mushrooms', 'green peppers', 'extra chees']

#假设青椒没了，用完了

for requested_toppong in requested_toppings:
    if requested_toppong == 'green peppers':
        print ("Sorry, we are out of green penppers right now.")
    else:
        print ("Adding " + requested_toppong + ".")

print ("
Finished making your pizza!")

Adding mushrooms.
Sorry, we are out of green penppers right now.
Adding extra chees.

Finished making your pizza!

5.4.2 确定列表不是空的

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?")

Are you sure you want a plain pizza?

5.4.3 使用多个列表

available_toppongs = ['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_toppongs:
        print ("Adding " + requested_topping + ".")
    else:
        print ("Sorry, we don't have " + requested_topping + ".")

print ("
Finished making your pizza!")

Adding mushrooms.
Sorry, we don't have french fries.
Adding extra cheese.

Finished making your pizza!

Caesar卢尚宇

2020年3月13日