# _*_ coding:utf-8 _*_

#######用户输入和while循环#######

#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)

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Tell me something, and I will repeat it back to you: Hello everyone!

Hello everyone!

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#有时候提示可能超过一行，可将提示存储在一个变量中，再将该变量传递给函数input()

prompt = "If you tell us who you are, we can personalize the message you see."

prompt += " What is your first name? "

name = input(prompt)

print(" Hello, " + name + "!")

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If you tell us who you are, we can personalize the message you see.

What is your first name? Eric

Hello, Eric!

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#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(" You're tall enough to ride!")

else:

print(" You'll be able to ride when you're a little older.")

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How tall are you, in inches? 71

You're tall enough to ride!

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#求模运算符

#它将两个数相除并返回余数

number = input("Enter a number, and I'll tell you if it's even or odd: ")

number = int(number)

if number % 2 == 0:

print(" The number " + str(number) + " is even.")

else:

print(" The number " + str(number) + " is odd.")

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Enter a number, and I'll tell you if it's even or odd: 42

The number 42 is even.

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#while循环简介

#while循环不断地运行，直到指定的条件不满足为止

#while循环从1数到5

current_number = 1

while current_number <= 5:

print(current_number)

current_number +=1

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1

2

3

4

5

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#让用户选择何时退出

prompt = " Tell me something, and I will repeat it back to you: "

prompt += " Enter 'quit' to end the program. "

message = ""

while message != 'quit':

message = input(prompt)

if message != 'quit':

print(message)

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Tell me something, and I will repeat it back to you:

Enter 'quit' to end the program. Hello everyone!

Hello everyone!

Tell me something, and I will repeat it back to you:

Enter 'quit' to end the program. Hello again.

Hello again.

Tell me something, and I will repeat it back to you:

Enter 'quit' to end the program. quit

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#使用标志

prompt = " Tell me something, and I will repeat it back to you: "

prompt += " Enter 'quit' to end the program. "

active = True

while active:

message = input(prompt)

if message == 'qiut':

active = False

else:

print(message)

#使用break退出循环

prompt = " Please enter the name of a city you have visited:"

prompt += " (Enter 'quit' when you are finished.) "

while True:

city = input(prompt)

if city == 'quit':

break

else:

print("I'd love to go to " + city.title() + "!")

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Please enter the name of a city you have visited:

(Enter 'quit' when you are finished.) New York

I'd love to go to New York!

Please enter the name of a city you have visited:

(Enter 'quit' when you are finished.) San Francisco

I'd love to go to San Francisco!

Please enter the name of a city you have visited:

(Enter 'quit' when you are finished.) quit

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#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)

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1

3

5

7

9

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#使用while循环来处理列表和字典（要在遍历列表的同时对其进行修改，可使用while循环）

#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() #函数pop()以每次一个的方式从列表unconfirmed_users末尾删除未验证的用户

print("verifying user: " + current_user.title())

confirmed_users.append(current_user)

#显示所有已验证的用户

print(" The following users have been confirmed:")

for confirmed_user in confirmed_users:

print(confirmed_user.title())

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verifying user: Candace

verifying user: Brian

verifying user: Alice

The following users have been confirmed:

Candace

Brian

Alice

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#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)

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['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']

['dog', 'dog', 'goldfish', 'rabbit']

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#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(" What is your name? ")

response = input("Which mountain would you like to climb someday? ")

#将答案存储在字典中

responses[name] = response

#看看是否还有人要参与调查

repeat = input("Would you like to let another person respond?(yes/ no) ")

if repeat == 'no':

polling_active = False

#调查结束，显示结果

print(" --- Poll Results ---")

for name, response in responses.items():

print(name + " would like to climb " + response + ".")

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What is your name? Eric

Which mountain would you like to climb someday? Denali

Would you like to let another person respond?(yes/ no) yes

What is your name? Lynn

Which mountain would you like to climb someday? Devil's Thumb

Would you like to let another person respond?(yes/ no) no

--- Poll Results ---

Eric would like to climb Denali.

Lynn would like to climb Devil's Thumb.

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