Python Learning(7) 用户输入和while循环

旧城等待， 2022-02-03 05:55 233阅读 0赞

python从入门到实践

""" chapter7 用户输入和while循环 """
    # 7.1 函数 input()的工作原理:函数input()让程序暂停运行，等待用户输入一些文本
    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 messages 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
    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
    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.")
    
    # 7.2 while 循环简介
    # 7.2.1 使用 while 循环
    number = 1
    while number <= 5:
        print(number)
        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)
    
    # 7.2.3 使用标志 -让while循环更简洁
    prompt = "\nTell me something, and I will repeat it back to you:"
    prompt += "\nEnter 'quit' to end the program. "
    flag = True
    while flag:
        message = input(prompt)
    
        if message == 'quit':
            flag = False
        else:
            print(message)
    
    # 7.2.4 使用 break 退出循环
    number = 1
    while number < 7:
        print(number)
        number += 1
        if number == 3:
            break
    
    print("--------------------")
    number = 1
    while number < 7:
        print(number)
        number += 1
        if number == 3:
            continue
    
    # 7.2.5 在循环中使用 continue
    # 打印10以内的所有奇数
    print("--------------------")
    number = 0
    while number < 10:
        number += 1
        if number % 2 == 0:
            continue
        print(number)
    
    # 7.2.6 避免无限循环 小心处理while循环，防止无限循环
    
    # 7.3 使用 while 循环来处理列表和字典
    # 7.3.1 在列表之间移动元素
    # 假设有一个列表，其中包含新注册但还未验证的网站用户；验证这些用户后，如何将他们移到另一个已验证用户列表中呢？
    print("--------------------")
    unconfirmed_users = ['zhangsan', 'lisi', 'wangwu']
    confirmed_users = []
    while len(unconfirmed_users) != 0:
        user = unconfirmed_users.pop()
        confirmed_users.append(user)
        print(user + "be confirmed")
    # 显示所有已验证的用户
    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
    print("7.3.2 --------------------")
    users = ['zhangsan', 'lisi', 'wangwu', 'zhangsan2']
    print(users)
    for user in users:
        if user.startswith("zhangsan"):
            users.remove(user)
    print(users)
    
    print("7.3.2 2--------------------")
    users = ['zhangsan', 'lisi', 'wangwu', 'zhangsan2']
    print(users)
    for user in users:
        while user.startswith("zhangsan"):
            users.remove(user)
            break  # 小心while循环带来的问题，少使用while循环
    print(users)
    
    # 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? ")
        responses[name] = response
        # 看看是否还有人要参与调查
        repeat = input("Would you like to let another person respond? (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 + " would like to climb " + response + ".")

练习：

# 7-1 汽车租赁：编写一个程序，询问用户要租赁什么样的汽车，并打印一条消息，如“Let me see if I can find you a Subaru”。
    # prompt = "\nWhat kind of car do you want to rent? "
    # car = input(prompt)
    # print("Let me see if I can find you a " + car + "!")
    
    # 7-2 餐馆订位：编写一个程序，询问用户有多少人用餐。如果超过 8 人，就打印一条消息，指出没有空桌；否则指出有空桌。
    # prompt = "\nHow many people do you have to eat? "
    # guest_number = input(prompt)
    # if int(guest_number) > 8:
    # print("There is no empty table here.")
    # else:
    # print("Follow me ,pls")
    
    # 7-3 10 的整数倍：让用户输入一个数字，并指出这个数字是否是 10 的整数倍。
    # prompt = "\ninput a number ,I can tell you if it is an integer multiple of 10 "
    # number = int(input(prompt))
    # if number % 10 == 0:
    # print("it is an integer multiple of 10。 ")
    # else:
    # print("it is not an integer multiple of 10。 ")
    #
    
    # 7-4 比萨配料：编写一个循环，提示用户输入一系列的比萨配料，并在用户输入'quit'时结束循环。每当用户输入一种配料后，
    # 都打印一条消息，说我们会在比萨中添加这种配料。
    # prompt = "\n请输入披萨配料： "
    # message = ""
    # while True:
    # message = input(prompt)
    # if 'quit' == message:
    # break
    # else:
    # print("我们会在披萨中添加这种配料！")
    
    # 7-5 电影票：有家电影院根据观众的年龄收取不同的票价：不到 3 岁的观众免费；3~12 岁的观众为 10 美元；
    # 超过 12 岁的观众为 15 美元。请编写一个循环，在其中询问用户的年龄，并指出其票价。
    
    # prompt = "\n请问你今年多大： "
    # while True:
    # age_str = input(prompt)
    # if not str(age_str).isnumeric():
    # break
    # else:
    # age = int(age_str)
    # if age < 3:
    # print("free!")
    # elif age > 3 and age < 12:
    # print("10$")
    # else:
    # print("15$")
    
    
    # prompt = "\n请问你今年多大： "
    # flag = True
    # while flag:
    # age_str = input(prompt)
    # if not str(age_str).isnumeric():
    # flag = False
    # else:
    # age = int(age_str)
    # if age < 3:
    # print("free!")
    # # elif age > 3 and age < 12:
    # elif 3 < age < 12:
    # print("10$")
    # else:
    # print("15$")
    
    
    # 7-8 熟食店：创建一个名为 sandwich_orders 的列表，在其中包含各种三明治的名
    # 字；再创建一个名为 finished_sandwiches 的空列表。遍历列表 sandwich_orders，对于
    # 其中的每种三明治，都打印一条消息，如 I made your tuna sandwich，并将其移到列表
    # finished_sandwiches。所有三明治都制作好后，打印一条消息，将这些三明治列出来。
    sandwich_orders = ['三明治1', '三明治2', '三明治3']
    finished_sandwiches = []
    for sandwich in sandwich_orders:
        print("I made your tuna sandwich")
        finished_sandwiches.append(sandwich)
    print(finished_sandwiches)
    
    # 7-9 五香烟熏牛肉（pastrami）卖完了：使用为完成练习 7-8 而创建的列表
    # sandwich_orders，并确保'pastrami'在其中至少出现了三次。在程序开头附近添加这样
    # 的代码：打印一条消息，指出熟食店的五香烟熏牛肉卖完了；再使用一个 while 循环将
    # 列表 sandwich_orders 中的'pastrami'都删除。确认最终的列表 finished_sandwiches 中
    # 不包含'pastrami'
    
    sandwich_orders = ['11', 'pastrami', '22', '33', 'pastrami', '44', 'pastrami']
    finished_sandwiches = []
    
    print("Pastrami has been sold out")
    
    while 'pastrami' in sandwich_orders:
        sandwich_orders.remove('pastrami')
    
    for sandwich in sandwich_orders:
        print("I made your " + sandwich + " sandwich.")
        finished_sandwiches.append(sandwich)
    
    for sandwich in finished_sandwiches:
        print(sandwich)
    
    # 7-10 梦想的度假胜地：编写一个程序，调查用户梦想的度假胜地。使用类似于“If
    # you could visit one place in the world, where would you go?”的提示，并编写一个打印调
    # 查结果的代码块。
    responses = { }
    polling_active = True
    while polling_active:
        name = input("\n What's u name?")
        place = input("\nIf you could visit one place in the world, where would you go?")
        responses[name] = place
        # 看看是否还有人要参与调查
        repeat = input("Would you like to let another person respond? (yes/ no) ")
        if repeat == 'no':
            polling_active = False
    # 调查结束，显示结果
    print("\n--- Poll Results ---")
    for name, pl in responses.items():
        print(name + " would like to visit " + pl + ".")