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Date: Wed, 22 Jun 2011 13:04:40 -0700
From: Ethan Furman <ethan@stoneleaf.us>
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To: Neal Becker <ndbecker2@gmail.com>
Subject: Re: writable iterators?
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:8242

Neal Becker wrote:
> AFAICT, the python iterator concept only supports readable iterators, not write.  
> Is this true?
> 
> for example:
> 
> for e in sequence:
>   do something that reads e
>   e = blah # will do nothing
> 
> I believe this is not a limitation on the for loop, but a limitation on the 
> python iterator concept.  Is this correct?

No.  e = blah will rebind the indentifier 'e' with 'blah' whatever that 
is.  That is how python works.

Now, if e is mutable, say a list, you can do

    e.append(blah)

and, since the name 'e' is not being rebound, you would see the change 
in 'sequence'.

~Ethan~