用户输入和while循环

input()

prompt = "If you tell us who you are, we can personalize the messages you see."
prompt += "
what is your first name? "

name = input(prompt)
print("
hello, " + name + "!")

输出：
If you tell us who you are, we can personalize the messages you see.
what is your first name? Eric

hello, Eric!

求模运算符：%，它将两个数相除并返回余数

print(4%3)

print(6%3)

print(1%3)

print(-1%3)  #为啥是2

输出： 
1
0
1
2

余数如果是0，可利用这点来判断奇/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:   #numbber % 2 == 0 ,number就是偶数，否则是奇数
    print("
The number " + str(number) + " is even.")
else:
    print("
The number " + str(number) + " is odd.")
输出：
Enter a number, and I'll tell you if it's even or odd: 5

The number 5 is odd.

while循环：不断地运行，知道指定的条件不满足为止。

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)
输出：
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

标记

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 == 'quit':
        active = False
    else:
        print(message)

break

prompt = "
PLS 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  #退出循环
    else:
        print("I'd love to go to " + city.title() + "!")
输出：

PLS enter the name of a city you have visited:
(Enter 'quit' when you are finished.) Beijing
I'd love to go to Beijing!

PLS enter the name of a city you have visited:
(Enter 'quit' when you are finished.) ShenYang
I'd love to go to Shenyang!

PLS enter the name of a city you have visited:
(Enter 'quit' when you are finished.) quit

continue

current_number = 0

while current_number < 10:
    current_number += 1
    if current_number % 2 == 0:
        continue
    
    print(current_number)
        
输出：
1
3
5
7
9

注：如果命令行出现无限循环，Ctrl+C退出

验证新注册用户，将未验证用户移动到已验证用户列表中

unconfirmed_users = ['alice','brian','candace']  #待验证用户
confirmed_users = []    #已验证的用户

while unconfirmed_users:   #验证每个用户
    current_user = unconfirmed_users.pop()
    
    print("Verifying user: " + current_user.title())
    confirmed_users.append(current_user)
#显示所有已验证用户
print("
The following users have been confirmed: ")
for confirmed_user in confirmed_users:
    print(confirmed_user.title())
    
输出：
Verifying user: Candace
Verifying user: Brian
Verifying user: Alice

The following users have been confirmed:
Candace
Brian
Alice

删除列表中所有的指定元素

pets = ['dog','cat','dog','goldfish','cat','rabbit','cat']
print(pets)

while 'cat' in pets:
    pets.remove('cat')

print(pets)
输出：
['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
['dog', 'dog', 'goldfish', 'rabbit']

responses = {}

active = True

while active:
    name = input("what's your name? ")
    response = input("what's your favorite language:")
    
    responses[name] = response
    
    repeat = input("go on?(yes/no)")
    if repeat == 'no':
        active = False
        
print("
 -- Result -- ")
for name,response in responses.items():
    print(name.title() + "'s favorite language is :" + response.title())
输出：
what's your name? alex
what's your favorite language:python
go on?(yes/no)yes
what's your name? suki
what's your favorite language:C
go on?(yes/no)no

 -- Result --
Alex's favorite language is :Python
Suki's favorite language is :C