def index(self):

[Jussi Salmela]

Gert Cuykens kirjoitti:
> Is there a difference between
> 
> <code>
> class HelloWorld:
> def index(self):
>  index.exposed = True
>  return "Hello world!"
> </code>
> 
> and
> 
> <code>
> class HelloWorld:
> def index(self):
>  self.exposed = True
>  return "Hello world!"
> </code>

The resident experts seemingly being absent for a while, I'll strike:

Yes: the first gives a runtime error and the second is OK.
I've renamed the second class to HelloWorld2 and then:

 >>> hw = HelloWorld()
 >>> hw2 = HelloWorld2()

 >>> hw.index()
Traceback (most recent call last):
   File "<pyshell#144>", line 1, in <module>
     hw.index()
   File "C:\Python\Dive into Python\Py\apihelper.py", line 40, in index
     index.exposed = True
NameError: global name 'index' is not defined

 >>> hw2.index()
'Hello world!'

The error message shows that the Python compiler has interpreted the 
construction 'index.exposed' to refer to a global variable 'index' that 
doesn't exist at run time. The second class succesfully defines an 
instance attribute 'exposed' as can be seen by:

 >>> print hw2.exposed
True

HTH
Jussi