Re: hasattr() or "x in y"?

From	Grant Edwards <invalid@invalid.invalid>
Newsgroups	comp.lang.python
Subject	Re: hasattr() or "x in y"?
Date	2016-03-11 22:30 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<nbvgum$5v6$1@reader1.panix.com> (permalink)
References	<nbve7c$nbo$1@dont-email.me> <nbvf69$105$1@reader1.panix.com> <nbvg8a$vcv$1@dont-email.me>

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On 2016-03-11, Charles T. Smith <cts.private.yahoo@gmail.com> wrote:
> On Fri, 11 Mar 2016 22:00:41 +0000, Grant Edwards wrote:
>
>> Since they behave differently, perhaps the question ought to be "which
>> does what you want to do?"
>
> For parsed msgs, I had this:
>
>               elif hasattr (msg.msgBody, 'request'):
>
> It occurred to me that this was less abstruse:
>
>               elif 'request' in msg.msgBody:

If you want to know if msg.msgBody has an attribute named 'request'
then use hasattr().

If you want to know if msg.msgBody "contains"[1] the string 'request'
then use "in".

_They're_two_different_things_

[1] for some definition of "contains" that depends on the type of
msg.msgBody.

> and by the way, how would you do that with duck-typing?

Do WHAT?

> If I were doing this anew, I probably use a dictionary of functors,
> but that's not an option anymore.

-- 
Grant Edwards               grant.b.edwards        Yow! Were these parsnips
                                  at               CORRECTLY MARINATED in
                              gmail.com            TACO SAUCE?

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Thread

hasattr() or "x in y"? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-03-11 21:44 +0000
  Re: hasattr() or "x in y"? Chris Angelico <rosuav@gmail.com> - 2016-03-12 08:55 +1100
  Re: hasattr() or "x in y"? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-03-11 21:53 +0000
    Re: hasattr() or "x in y"? Chris Angelico <rosuav@gmail.com> - 2016-03-12 09:04 +1100
    Re: hasattr() or "x in y"? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-11 22:05 +0000
  Re: hasattr() or "x in y"? Grant Edwards <invalid@invalid.invalid> - 2016-03-11 22:00 +0000
    Re: hasattr() or "x in y"? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-03-11 22:18 +0000
      Re: hasattr() or "x in y"? Grant Edwards <invalid@invalid.invalid> - 2016-03-11 22:30 +0000

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