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From: Grant Edwards <invalid@invalid.invalid>
Newsgroups: comp.lang.python
Subject: Re: hasattr() or "x in y"?
Date: Fri, 11 Mar 2016 22:30:46 +0000 (UTC)
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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?