Re: Unicode Objects in Tuples

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From	Roy Smith <roy@panix.com>
Newsgroups	comp.lang.python
Subject	Re: Unicode Objects in Tuples
Date	Sat, 12 Oct 2013 09:11:00 -0400
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In article <mailman.1034.1381575143.18130.python-list@python.org>,
 Ned Batchelder <ned@nedbatchelder.com> wrote:

> This idea that the repr can reconstruct the object always fell flat with 
> me since the vast majority of classes don't have a repr that works that 
> way.  I look at it a little differently: the repr is meant to be as 
> unambiguous as possible to a developer.  It turns out that Python 
> literal syntax is really good at that, so where possible, that's what's 
> used.   But most classes don't make an attempt to create a Python 
> expression, because that's very difficult

Well, it's not actually difficult.  You could imagine doing something 
like:

def __repr__(self):
    return "pickle.loads(%s)" % pickle.dumps(self)

and while you can paste that into a REPL, it's not really useful to most 
people.

What we do with our database model layer is have the repr include the 
name of the class and the primary key.  So:

>>> str(u)
'roysmith'
>>> repr(u)
"<User 1000564: u'roysmith'>"

That follow's Ned's idea that reprs should be unambiguous.  In this 
case, if I want to reconstitute myself as an object, I can just do a 
database query for user_id = 1000564.

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Re: Unicode Objects in Tuples Ned Batchelder <ned@nedbatchelder.com> - 2013-10-12 06:52 -0400
  Re: Unicode Objects in Tuples Roy Smith <roy@panix.com> - 2013-10-12 09:11 -0400

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