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Date: Sat, 29 Mar 2014 17:46:53 -0500
From: Tim Chase <tim@thechases.com>
To: Roy Smith <roy@panix.com>
Subject: Re: checking if two things do not equal None
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Xref: csiph.com comp.lang.python:69352

On 2014-03-29 18:41, Roy Smith wrote:
> On Mar 29, 2014, at 6:36 PM, Tim Chase wrote:
> 
> > And for cases where you have more than one or two things to test
> > for None-itude, you could use
> > 
> >  if all(x is None for x in [a, b, c, d]):
> >    do_something_if_theyre_all_None()
> 
> I might have written that as:
> 
> if set([a, b, c, d]) == set(None)
> 
> That's even clearer if you happen to already have the items in an
> iterable:
> 
> if set(conditions) == set(None)

Though am I correct that your iteration tests for equality, while
mine tests for identity?  Also, my version bails early in the event
quitting early is possible.  That's particularly useful in the case
of doing something like

  if all(x() is None for x in [func1, func2, func3, costly_func]):
    do_something()

-tkc