#input假设用户输入的是合法的Python表达式
>>> name = input("what is your name?")
what is your name?ZJ
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "<string>", line 1, in <module>
NameError: name 'ZJ' is not defined

#于是，必须这么使用，输入Python格式的字符串"ZJ"
>>> name = input("what is your name?")
what is your name? "ZJ"
>>> print name
ZJ
>>> 

#raw_input会把所有输入当作原始数据(raw data)，然后将其放入字符串中
>>> name = raw_input("what is your name?")
what is your name?ZJ
>>> print name
ZJ
>>>