day①:python的用户交互

  py2           py3
①input() --> eval(input)
#eval()作用：把字符串当作变量

py2:
>>> var=input("please input your name:")
please input your name:hy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <module>
NameError: name ‘hy‘ is not defined
>>> var=input("please input your name:")
please input your name:"hy"           ##输入字符串或者字符的时候，要用双引号或者单引号包起来
>>> var
‘hy

py2:
>>> var=input("please input your name:")
please input your name:yaobin
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <module>
NameError: name ‘yaobin‘ is not defined
>>> yaobin="hy"
>>> var=input("please input your name:")
please input your name:yaobin
>>> var
‘hy‘
##py2的input()是一个特殊的raw_input(),只是外层调用了eval()函数而已。

py3:
>>> eval(input("your name:"))
your name:yaobin
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <module>
NameError: name ‘yaobin‘ is not defined
>>> yaobin="hy"
>>> eval(input("your name:"))
your name:yaobin
‘hy‘



  py2           py3
②raw_input --> input() 
py2:
>>> raw_input("your name:")
your name:abc               #不管你输入什么样的类型，都会转变成字符串
‘abc‘

py3:
>>> input("your name:")
your name:abc
‘abc‘
>>>