Python编程 从入门到实践-5if语句中

笔记出处(学习UP主视频记录) https://www.bilibili.com/video/av35698354?p=9

5.3 if语句

5.3.1 简单的if语句

if conditional_test:
    do somthing

age = 19
if age >= 18:
    print ("You are old enough to vote!")

You are old enough to vote!

5.3.2 if-else语句

age = 17
if age >= 18:
    print ("You are old enough to vote!")
    print ("Have you registered to vote yet?")
else:
    print ("Sorry, you are too young to vote.")
    print ("Please register to vote as soon as you turn 18!")

Sorry, you are too young to vote.
Please register to vote as soon as you turn 18!

5.3.3 if-elif-else结构

#根据年龄段收费的游乐场
#4岁以下免费
#4~18岁收费$5
#18岁（含）以上收费$10

age = 12

if age < 4:
    print ("Your admission cost is $0.")
elif age < 18:
    print ("Your admission cost is $5.")
else:
    print ("Your admission cost is $10.")

Your admission cost is $5.

5.3.4 使用多个elif代码块

age = 12

if age < 4:
    price = 0
elif age < 18:
    price = 5
elif age < 65:
    price = 10
else:
    price = 5 #age>65

print ("Your admission cost is $" + str(price) + ".")

Your admission cost is $5.

5.3.5 省略else代码块

age = 12

if age < 4:
    price = 0
elif age < 18:
    price = 5
elif age < 65:
    price = 10
elif age >= 65:
    price = 5

print ("Your admission cost is $" + str(price) + ".")

Your admission cost is $5.

5.3.6 测试多个条件

#如果顾客点了2种配料，就需要确保在其比萨种包含这些配料
requested_toppings = ['mushrooms', 'extra cheese']
if 'mushrooms' in requested_toppings:
    print ("Adding mushrooms.")
if 'pepperoni' in requested_toppings:
    print ("Adding pepperoni.")
if 'extra cheese' in requested_toppings:
    print ("Adding extra chees.")

print ("
Finished making your pizza!")

Adding mushrooms.
Adding extra chees.

Finished making your pizza!

Caesar卢尚宇

2020年3月12日