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Groups > comp.lang.python > #101860

Re: "x == None" vs "x is None"

From Random832 <random832@fastmail.com>
Newsgroups comp.lang.python
Subject Re: "x == None" vs "x is None"
Date 2016-01-17 16:33 -0500
Message-ID <mailman.75.1453066407.15297.python-list@python.org> (permalink)
References <n7fo7q$dso$1@news2.informatik.uni-stuttgart.de> <mailman.57.1453025729.15297.python-list@python.org> <n7fshb$f36$1@news2.informatik.uni-stuttgart.de> <CAPTjJmrDZCiDLmRtiukDv2Z1Gz69fz3+_4xYeu-PoXBdC3dtGg@mail.gmail.com> <CAJ4+4aoHHzFJNHvw+LjimO6qHr6dsUskMsQw6y+uiW0jrQzm-w@mail.gmail.com>

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<paul.hermeneutic@gmail.com> writes:

> I prefer (x is None) and (x is not None).
>
> This matches the SQL concept of NULL.
>
> (X = NULL) is not valid since NULL is not a value and cannot be compared
> with anything.

The suitably generic SQL operator is "is (not) distinct from", in some
dialects of SQL [certainly if you're using NULL directly you can simply
use is/is not, but the "distinct from" operators can be used to compare
two expressions that may either or both be NULL.

"X is not distinct from Y" == "X = Y or X is NULL and Y is NULL"

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Thread

"x == None" vs "x is None" Ulli Horlacher <framstag@rus.uni-stuttgart.de> - 2016-01-17 09:51 +0000
  Re: "x == None" vs "x is None" Chris Angelico <rosuav@gmail.com> - 2016-01-17 21:15 +1100
    Re: "x == None" vs "x is None" Ulli Horlacher <framstag@rus.uni-stuttgart.de> - 2016-01-17 11:05 +0000
      Re: "x == None" vs "x is None" Peter Otten <__peter__@web.de> - 2016-01-17 12:26 +0100
      Re: "x == None" vs "x is None" Chris Angelico <rosuav@gmail.com> - 2016-01-17 22:29 +1100
      Re: "x == None" vs "x is None" <paul.hermeneutic@gmail.com> - 2016-01-17 11:01 -0700
      Re: "x == None" vs "x is None" Random832 <random832@fastmail.com> - 2016-01-17 16:33 -0500
      Re: "x == None" vs "x is None" Chris Angelico <rosuav@gmail.com> - 2016-01-18 08:38 +1100
      Re: "x == None" vs "x is None" Ben Finney <ben+python@benfinney.id.au> - 2016-01-18 13:46 +1100
  Re: "x == None" vs "x is None" fernando junior <fernandojr.ifcg@live.com> - 2016-01-19 14:20 -0800

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