Is there a way to pring a list object in Python?

Richard Thomas chardster at gmail.com
Sun Oct 31 20:38:00 CET 2010


On Oct 31, 7:04 pm, Zeynel <azeyn... at gmail.com> wrote:
> On Oct 31, 5:52 am, Dave Angel <da... at ieee.org> wrote:
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> > On 2:59 PM, Zeynel wrote:> class Rep(db.Model):
> > >      author = db.UserProperty()
> > >      replist = db.ListProperty(str)
> > >      unique = db.ListProperty(str)
> > >      date = db.DateTimeProperty(auto_now_add=True)
>
> > > ....
>
> > > Rep().replist = L
> > > Rep().put()
> > > mylist = Rep().all().fetch(10)
>
> > > I am trying to display mylist; but I am getting the object. Thanks.
>
> > I don't know any meaning for "pring."
>
> > Care to mention what db is?  Presumably it's some other module, not in
> > the standard library, that you've imported.  And presumably it has a
> > class called Model defined in it.
>
> > But the three lines following make no sense to me in isolation, so
> > unless you know how db.Model is intended to be used, I can't imagine
> > what you expect here.  Rep().replist = L  creates a temporary object,
> > gives it an attribute, and throws them both away.  Although I could
> > write code that would have enough side effects to do something with
> > that, I can't imagine why I would want to.
>
> > Be more explicit with the assumptions (in this case, at least show the
> > import), and with the results.  So instead of saying "I am getting the
> > object," say
>
> > print mylist
>
> > produces the output:
>
> > sjfdsljdsfds;lkjfdsfds
> > fdsljfds;ldsj;dslkjfds
> > dsfjlfkjslkjfd s fj lkjfd
>
> > DaveA
>
> I am using Google App Engine, but it seems that the problem is a
> Python problem. I fixed the code a little bit, now I can print the
> lists:
>
>         Rep().replist = L
>         Rep().put()
>         query = Rep.all()
>         for result in query:
>             self.response.out.write(result.replist)
>
> The output of this is:
>
> [u'a', u'b'][u'a', u'b'][u'a', u'b']. . .
>
> So, these are the lists in datastore. I want to take one of these
> lists and apply list method on it. How do I do that? Thanks.

Okay that <Rep object at 0x....> is the representation of the object.
If you want to control how an object is represented when you put it in
a template you should define a __str__ method:

class Rep(db.model):
    # Properties
    ...
    # Representation
    def __str__(self):
        return "\n".join(self.replist)

Or however you want to object to appear. It may help to do a few
experiments outside GAE in the interactive interpreter.

Richard.



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