Python第七章

# 第 7 章 用户输入和while循环
# 7.1 函数input()的工作原理
# message = input("Tell me something, and I will repeat it back to you: ")
# print(message)

# 7.1.1 编写清晰的程序
# name = input("Please enter your name: ")
# print("Hello, " + name + "!")

# prompt = "If you tell us who you are, we can personalize the message you see."
# prompt += "\nWhat is your first name? "
# name = input(prompt)
# print("\nHello, " + name + "!")

# 7.1.2 使用int()来获取数值输入
# age = input("How old are you? ")
# print("I'm " + str(age) + ".") # 可转化为字符串再打印输出，间接的赋值数字必须转化为字符串再输出打印，否则打印会出错
# print("I'm " + age + ".") # 输入的数字age为字符串可直接打印

# age = input("How old are you? ") # 此处age为字符串，需用int()转换为数字才能跟数字比较大小
# age >= 18

# age = input("How old are you? ")
# age = int(age)
# if age >= 18:
# print("Yes!")

# 判断一个人是否满足坐过山车的身高要求
# height = input("How tall are you, in inches? ")
# height = int(height)
# if height >= 36:
# print("\nYou 're tall enough to ride!")
# else:
# print("\nYou'll be able to ride when you're a little older.")

# 7.1.3 求模运算符
a = 4 % 3
print(a)
b = 5 % 3
print(b)
c = 6 % 3
print(c)

# 如果一个数可被另一个数整除，余数就为0，因此求模运算符将返回0。
# 你可利用这一点来判断一个数是奇数还是偶数。
# number = input("Enter a number, and I'll tell you if it's even or odd: ")
# number = int(number)
# if number % 2 == 0:
# print("\nThe number " + str(number) + " is even.")
# else:
# print("\nThe number " + str(number) + " is odd.")

# 如果你使用的是Python 2.7，应使用函数raw_input() 来提示用户输入。这个函数与Python 3中的input() 一样，也将输入解读为字符串。

# 7-1 汽车租赁
# car = input("What kind of car would you like? ")
# print("Let me see if I can find you a " + car.title() + ".")

# 7-2 餐馆订位
# number = input("How many people are in your dinner party tonight? ")
# number = int(number)
# if number > 8:
# print("I'm sorry, you'll have to wait for a table.")
# else:
# print("Your table is ready.")

# 7-3 10的整数倍
# number = input("Please enter a number: ")
# number = int(number)
# if number % 10 == 0:
# print(str(number) + " is a multiple of 10.")
# else:
# print(str(number) + " is not a multiple of 10.")

# 7.2.1 使用while循环
current_number = 1
while current_number <= 5:
print(current_number)
current_number += 1 # current_number = current_number + 1

# 7.2.2 让用户选择何时退出
# prompt = "\nTell me something, and I will repeat it back to you:"
# prompt += "\nEnter 'quit' to end the program."
# message = ""
# while message != 'quit':
# message = input(prompt)
# print(message)

# prompt = "\nTell me something, and I will repeat it back to you:"
# prompt += "\nEnter 'quit' to end the program."
# message = ""
# while message != 'quit':
# message = input(prompt)
#
# if message != 'quit':
# print(message)

# 7.2.3 使用标志
# prompt = "\nTell me something, and I will repeat it back to you:"
# prompt += "\nEnter 'quit' to end the program. "
#
# active = True
# while active:
# message = input(prompt)
# if message == 'quit':
# active = False
# else:
# print(message)

# 7.2.4 使用break 退出循环
# 注意 在任何Python循环中都可使用break 语句。例如，可使 用break 语句来退出遍历列表或字典的for 循环。
# prompt = "\nPlease enter the name of a city you have visited:"
# prompt += "\n(Enter 'quit' when you are finished.) "
#
# while True:
# city = input(prompt)
# if city == 'quit':
# break
# else:
# print("\nI'd love to go to " + city.title() + ".")

# 7.2.5 在循环中使用continue
current_number = 0
while current_number < 10:
current_number += 1
if current_number % 2 == 0:
continue
print(current_number)

# 7.2.6 避免无限循环
x = 1
while x <= 5:
print(x)
x += 1 # 没这句程序会无限循环下去

# 7-4 披萨配料
# prompt = "\nWhat topping would you like on your pizza?"
# prompt += "\nEnter 'quit' when you are finished: "
# while True:
# topping = input(prompt)
# if topping != 'quit':
# print(" I will add " + topping + " to your pizza.")
# else:
# break

# 7-5 电影票
# prompt = "\nHow old are you? We will tell you the prize."
# prompt += "\nEnter 'quit' when you are finished. "
#
# while True:
# age = input(prompt)
# if age == 'quit':
# break
# age = int(age)
#
# if age < 3:
# print(" You get in free!")
# elif age < 12:
# print(" Your ticket is 10 dollars.")
# else:
# print(" Your ticket is 15 dollars.")

# 7-6 三个出口
# prompt = "\nWhat topping would you like on your pizza?"
# prompt += "\nEnter 'quit' when you are finished: "
# active = True
# while active:
# topping = input(prompt)
# if topping != 'quit':
# print(" I will add " + topping + " to your pizza.")
# else:
# active = False

# 7.3.1 在列表之间移动元素
# 首先，创建一个待验证用户列表和⼀个⽤于存储已验证⽤户的空列表
unconfirmed_users = ['alice', 'brian', 'candace']
confirmed_users = []
# 验证每个用户，直到没有未验证用户为止
# 将每个经过验证的列表都移到已验证用户列表中
while unconfirmed_users:
current_user = unconfirmed_users.pop()
print("Verifying user: " + current_user.title())
confirmed_users.append(current_user)
# 显示已验证的用户
print("\nThe following users have been confirmed:")
for confirmed_user in confirmed_users:
print(confirmed_user.title())

# 7.3.2 删除包含特定值的所有列表元素
pets = ['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
print(pets)
while 'cat' in pets:
pets.remove('cat')
print(pets)

# 7.3.3 使用用户输入来填充字典
# responses = {}
# 设置一个标志，指出调查是否继续
# polling_active = True
# while polling_active:
# # 提示输入被调查者的名字和回答
# name = input("\nWhat is your name? ")
# response = input("Which mountain would you like to climb someday? ")
# # 将答卷存储在字典中
# responses[name] = response
# # 看看是否还有人要参与调查
# repeat = input("Would you like to let another person response? (yes/no) ")
# if repeat == 'no':
# polling_active = False
# # 调查结束，显示结果
# print("\n--- Poll Results ---")
# for name, response in responses.items():
# print(name.title() + " would like to climb " + response.title() + ".")

# 7-8 熟食店
sandwich_orders = ['tuna', 'veggie', 'grilled cheese', 'turkey', 'roast beef']
finished_sandwiches = []
for sandwich in sandwich_orders:
print("\nI made your " + sandwich + " sandwich.")
finished_sandwiches.append(sandwich)
print("Here are the finished sandwiches:")
for sandwich in finished_sandwiches:
print(sandwich)

sandwich_orders = ['tuna', 'veggie', 'grilled cheese', 'turkey', 'roast beef']
finished_sandwiches = []
while sandwich_orders:
current_sandwich = sandwich_orders.pop()
print("I'm working on your " + current_sandwich + " sandwich.")
finished_sandwiches.append(current_sandwich)
print("\n")
for sandwich in finished_sandwiches:
print("I made a " + sandwich + " sandwich.")

# 7-9 五香烟熏牛肉（pastrami）卖完了
sandwich_orders = ['pastrami', 'tuna', 'pastrami', 'veggie', 'grilled cheese', 'pastrami', 'turkey', 'roast beef']
finished_sandwiches = []
print("I'm sorry, we're all out of pastrami today.")
while sandwich_orders:
current_sandwich = sandwich_orders.pop()
if current_sandwich != 'pastrami':
finished_sandwiches.append(current_sandwich)
print("I'm working on your " + current_sandwich + " sandwich.")
print("\n")
for sandwich in finished_sandwiches:
print("I made a " + sandwich + " sandwich.")

sandwich_orders = ['pastrami', 'tuna', 'pastrami', 'veggie', 'grilled cheese', 'pastrami', 'turkey', 'roast beef']
finished_sandwiches = []
print("I'm sorry, we're all out of pastrami today.")
while 'pastrami' in sandwich_orders:
sandwich_orders.remove('pastrami')
print("\n")
while sandwich_orders:
current_sandwich = sandwich_orders.pop()
print("I'm working on your " + current_sandwich + " sandwich.")
finished_sandwiches.append(current_sandwich)
print("\n")
for sandwich in finished_sandwiches:
print("I made a " + sandwich + " sandwich.")

# 7-10 梦想的度假胜地
responses = {}
name_prompt = "\nWhat's your name? "
place_prompt = "If you want to visit one place in the world, what would it be? "
continue_prompt = "\nWould you like to let someone else respond? (yes/no) "
while True:
name = input(name_prompt)
place = input(place_prompt)
responses[name] = place
repeat = input(continue_prompt)
if repeat != 'yes':
break
print("\n--- Results ---")
for name, place in responses.items():
print(name.title() + " would like to visit " + place.title() + ".")