python从入门到实践第七章——输入与循环

'''
函数input()的工作原理：让程序暂停，等待用户输入。在终端输入与输出。
'''
message = input('Tell me something,and I will repeat it back to you: ')
print(message)
name = input('Please enter your name:')
print('hello,'+name+'!')
'''
多行内容输入：将字符串存入变量里，然后再传给input()。input()输入的只是字符串。
'''
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.title()+'!')
'''
使用int()来获取数值输入
'''
age = input('How old are you?')
if int(age) >= 18:
print('true')
'''如果是if age >= 18:则会出现错误，程序无法执行。因为input（）将接收的内容全部转换为字符串。'''
'''
判断一个人是否满足过山车的身高
'''
height = input('How tall are you,in inches?')
height =int(height)
if height >= 36:
print('you are tall enough to ride!')
else:
print('you will be able to ride when you are a little older.')
print('-------')
height = input('How tall are you,in inches?')
if int(height) >= 36:
print('you are tall enough to ride!')
else:
print('you will be able to ride when you are a little older.')
'''
求模运算符：%将两个数相除并返回余数。
'''
number = input('enter a number ,and I will 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')
'''
while循环
'''
current_number = 1
while current_number <= 5:
print(current_number)
current_number += 1
'''
for 语句表示的循环
'''
print('--------')
for current_number in range(1,6):
print(current_number)
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)

'''
for 语句表示的循环
'''
print('--------')
for current_number in range(1,6):
print(current_number)
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':#如果输入的为quit则不输出quit而直接结束。
print(message)
'''
使用标志---用于多条件判断
'''
print('--------')
prompt = '\nTell me something, and I will repeat it back to you:'
prompt += '\nEnter "quit" to end the program. '#在字符串中要用""而不要重复用''
active = True
while active:
message = input(prompt)
if message == 'quit':
active = False
else:
print(message)
'''
退出循环：
1、break:直接跳出整个循环,不在运行循环中的余下代码
2、cotinue:返回到循环开头，并根据条件测试结果决定是否继续执行循环。
'''
print('--------')
prompt = '\nplease enter a name of a city you have visited:'
prompt += '\nEnter "quit" when you are finished. '#在字符串中要用""而不要重复用''
while True :
city = input(prompt)
if city == 'quit':
break
else:
print('I`d love to go to '+city.title()+'!')
print('--------')
current_number = 0
for current_number in range(1,11):
if current_number % 2 == 1:
print(current_number)
print('--------')
current_number = 0
while current_number < 10:
current_number += 1
if current_number % 2 == 0:
continue#此处若没有continue将会出错。
print(current_number)

'''
for与while 的用法区别：
for 是遍历列表，便利时不应修改列表。
while是遍历的同时修改列表
'''
'''
列表之间移动元素
'''
unconfirmed_users = ['alice','brain','candace']
confirmed_users = []
while unconfirmed_users :
current_user = unconfirmed_users.pop()
confirmed_users.append(current_user)
print('\nThe following users have been confirmed:')
for confirmed_user in confirmed_users:
print(confirmed_user.title())
'''
删除包含特定值的所有列表元素：
.remove()
'''
pets = ['dog','cat','dog','goldfish','cat','rabbit','cat']
print(pets)
while 'cat' in pets:
pets.remove('cat')
print(pets)
'''
使用用户输入来填充字典。
'''
responses = {}
polling_active = True
while polling_active:
name = input('\nWhat is your name?')
response = input('which moutain would you like to climb someday?')
responses[name] = response
repeat = input('Would you like to let another person respond?(yes/no)')
if repeat == 'no':
polling_active = False
print('\n---- poll Result----')
for name,response in responses.items():
print(name+' would like to climb'+response+'.')