None assigment

[Simon Brunning]

> From:	Gregoire Welraeds [SMTP:greg at perceval.be]
> > After doing "None = 2", you can "del None" to get the default value 
> > back.
 
Hmm. This is true - I didn't know that.
 
> If we follow that logic, I could use any non assigned variable to have the
> following working:
> 
> >>> a= [1,'',3]
> >>> filter(b,a)
> 
> but this won't work as the interpreter complains that there is no variable
> named b.
 
You can't do this with *ordinary* labels - by del'ing them, you are
un-assigning them. But the 'None' label is *extraordinary*, obviously.
 
> It seems that (the so called variable) None is neither a variable like any
> other, nor is it a label as stated by Simon Brunning in another post.
 
It *is* a label - try this:

>>>print None
None
>>> None = 'spam'
>>> print None
spam

So, clearly, None is a label.
 
	 Now that I look at this problem, I'm totally confused about None.
Any
> explanaition is welcome. Anyway, I don't understand that one can override
> None. Could you give me at least one single good reason to do that.
 
I can give you a good reason *not* to - it will confuse the hell out of
people. ;-)

I'm sure one of the Python gurus will give you a bit more background, but I
think that the short answer is this - leave 'None' alone to get on with its
job, and you won't have any problems.

Cheers,
Simon Brunning
TriSystems Ltd.
sbrunning at trisystems.co.uk




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