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Groups > comp.lang.python > #100990

Re: using __getitem()__ correctly

From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: using __getitem()__ correctly
Date 2015-12-31 00:11 +1100
Message-ID <mailman.70.1451481087.11925.python-list@python.org> (permalink)
References <n60kcc$h89$1@dont-email.me>

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On Wed, Dec 30, 2015 at 11:57 PM, Charles T. Smith
<cts.private.yahoo@gmail.com> wrote:
> Hello,
>
> I thought __getitem__() was invoked when an object is postfixed with an
> expression in brackets:
>
>   - abc[n]
>
> and __getattr__() was invoked when an object is postfixed with an dot:
>
>   - abc.member

That would be normal (with the caveat that __getattr__ is called only
if the attribute isn't found; __getattribute__ is called
unconditionally).

> but my __getitem__ is being invoked at this time, where there's no
> subscript (going into a spiral recursion death):
>
>   self.mcc = self.attrs.mcc
>
> Can anybody explain to me why __getitem__()  would be invoked here?

Can you post your entire class, or at least __getattr__? Also check
superclasses, if there are any.

ChrisA

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Thread

using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 12:57 +0000
  Re: using __getitem()__ correctly Chris Angelico <rosuav@gmail.com> - 2015-12-31 00:11 +1100
    Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 14:40 +0000
      Re: using __getitem()__ correctly Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-30 08:35 -0700
        Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 16:58 +0000
          Re: using __getitem()__ correctly Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-30 13:40 -0700
            Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 22:54 +0000
              Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 22:58 +0000
              Re: using __getitem()__ correctly Ben Finney <ben+python@benfinney.id.au> - 2015-12-31 10:13 +1100
                Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-30 23:18 +0000
                Re: using __getitem()__ correctly Steven D'Aprano <steve@pearwood.info> - 2015-12-31 10:50 +1100
                Re: using __getitem()__ correctly Ben Finney <ben+python@benfinney.id.au> - 2015-12-31 11:21 +1100
                Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-31 11:30 +0000
                Re: using __getitem()__ correctly Ben Finney <ben+python@benfinney.id.au> - 2015-12-31 22:51 +1100
                Re: using __getitem()__ correctly Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-12-31 12:12 +0000
                Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-31 13:39 +0000
                Re: using __getitem()__ correctly Steven D'Aprano <steve@pearwood.info> - 2016-01-01 02:03 +1100
                Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-31 11:17 +0000
                Re: using __getitem()__ correctly Steven D'Aprano <steve@pearwood.info> - 2016-01-01 01:43 +1100
              Re: using __getitem()__ correctly Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-30 17:31 -0700
                Re: using __getitem()__ correctly "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2015-12-31 12:45 +0000

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