Noob Python代码不会工作

Question

我得到这个工作，它似乎很简单，但它不会。

bob = raw_input("What do you need?") 
if bob is "Hello": 
    sayhello() 

def sayhello(): 
    print"yo" 

Answer 1

使用值比较操盘==，is检查引用（short answer I wrote onis，其official doc）。

def sayhello(): 
    print"yo" 

bob = raw_input("What do you need?") 
if bob == "Hello": 
    sayhello() 

Answer 2

mrdomoboto为您提供解决方案。但是一点背景信息从来都不错。

is如果两个变量指向相同的对象，则返回True。

>>> a = [2, 3] 
>>> b = a 
>>> b is a 
True 
>>> b == a 
True 
>>> b = a[:] 
>>> b is a 
False 
>>> b == a 
True