On 31/03/14 19:28, Abe wrote:
I couldn't see anyone else give this, but I like
if None not in (a, b):
I did.
I am now considering:
if None not in (a,b):
or
if (a is not None) and (b is not None):
That's just
if not (a is None or b is None):
but you seem to have found your way.
However, I
> I couldn't see anyone else give this, but I like
> if None not in (a, b):
I did.
> I am now considering:
> if None not in (a,b):
> or
> if (a is not None) and (b is not None):
However, I decided to just turn the two parameters into one (sequence), since
they were logically grouped anyhow.
contact.tri...@gmail.com wrote:
> if (a, b) != (None, None):
> or
> if a != None != b:
>
> Preference? Pros? Cons? Alternatives?
I couldn't see anyone else give this, but I like
if None not in (a, b):
pass
Jeremy
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Roy Smith wrote:
Adding to the
confusion, many designs would use "active low" logic, which means a 1
was represented by a low voltage, and a 0 by a high voltage. So, you
quickly end up with gibberish like, "not active low clear nand not
active low enable clock".
There are ways of dealing wi
On 2014-03-30 13:21, Roy Smith wrote:
In article <5337b4e4$0$29994$c3e8da3$54964...@news.astraweb.com>,
Steven D'Aprano wrote:
I think Johannes got it right: boolean logic is easier to reason about
when there is a minimum of "not"s.
I used to do a lot of digital logic design. In certain l
In article <5337b4e4$0$29994$c3e8da3$54964...@news.astraweb.com>,
Steven D'Aprano wrote:
> I think Johannes got it right: boolean logic is easier to reason about
> when there is a minimum of "not"s.
I used to do a lot of digital logic design. In certain logic families,
it's easier to build a
Gregory Ewing :
> a != b != c
>
> does *not* imply that a != c. At least it doesn't in Python; I've
> never seen any mathematicians write that, so I don't know what they
> would make of it.
Any resemblance between mathematics notation and Python is purely
coincidental. I must admit I had missed
On Sun, Mar 30, 2014 at 5:52 PM, Ben Finney wrote:
> Chris Angelico writes:
>
>> The problem isn't that I can't see what the comparisons are. It makes
>> very good sense to bound a variable within constants; but you already
>> know exactly where 2 is on the number line, so asking "Is 2 between
>>
Chris Angelico writes:
> The problem isn't that I can't see what the comparisons are. It makes
> very good sense to bound a variable within constants; but you already
> know exactly where 2 is on the number line, so asking "Is 2 between
> these two variables" seems a bit odd. Maybe it's less so w
Roy Smith wrote:
But, if you show me
a != None != b:
my brain just goes into overload.
Chained comparisons get weird with not-equal operators.
If you see
a == b == c
then it implies that a == c, but
a != b != c
does *not* imply that a != c. At least it doesn't in
Python; I've never s
On Sun, Mar 30, 2014 at 4:54 PM, Steven D'Aprano
wrote:
> On Sun, 30 Mar 2014 13:15:18 +1100, Chris Angelico wrote:
>
>> Chained comparisons where you're checking a single variable against two
>> constants make perfect sense:
>>
>> 2 < x < 5
>>
>> Chained comparisons where you check a single const
On Sat, 29 Mar 2014 19:54:09 -0700, Rustom Mody wrote:
> On Sunday, March 30, 2014 8:09:45 AM UTC+5:30, Roy Smith wrote:
>> I have no particular problem with
>
>> x < 2 < y
>
>> because it fits the same pattern. But, if you show me
>
>> a != None != b:
>
>> my brain just goes into overload.
On Sun, 30 Mar 2014 13:15:18 +1100, Chris Angelico wrote:
> On Sun, Mar 30, 2014 at 1:04 PM, Steven D'Aprano
> wrote:
>> On Sat, 29 Mar 2014 17:07:20 -0400, Roy Smith wrote:
>>
>>> I certainly agree that things like
>>>
if a is not b is not None: ...
>>>
>>> belong in an obfuscated coding co
On March 29, 2014 9:43:00 PM CDT, Roy Smith wrote:
>In article <5337807b$0$29994$c3e8da3$54964...@news.astraweb.com>,
> Steven D'Aprano wrote:
>
>> a is b is c is None
>
>And we are all together. See how they run like pigs from a gun, see
>how
>they fly.
I'm cryin'.
(Really, that was terrib
On Sunday, March 30, 2014 8:09:45 AM UTC+5:30, Roy Smith wrote:
> I have no particular problem with
> x < 2 < y
> because it fits the same pattern. But, if you show me
> a != None != b:
> my brain just goes into overload. Honestly, I don't even know what that
> means. My brain keeps tryin
In article <5337807b$0$29994$c3e8da3$54964...@news.astraweb.com>,
Steven D'Aprano wrote:
> a is b is c is None
And we are all together. See how they run like pigs from a gun, see how
they fly.
--
https://mail.python.org/mailman/listinfo/python-list
In article ,
Chris Angelico wrote:
> Chained comparisons where you're checking a single variable against
> two constants make perfect sense:
>
> 2 < x < 5
>
> Chained comparisons where you check a single constant against two
> variables don't, so much:
>
> x < 2 < y
To me, chained comparison
On Sat, 29 Mar 2014 17:36:55 -0500, 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()
>
> or
>
> if all(x is not None for x in [a, b, c, d])
On Sun, Mar 30, 2014 at 1:04 PM, Steven D'Aprano
wrote:
> On Sat, 29 Mar 2014 17:07:20 -0400, Roy Smith wrote:
>
>> I certainly agree that things like
>>
>>> if a is not b is not None: ...
>>
>> belong in an obfuscated coding contest.
>
> Apart from the fact that I got it wrong (that's what happen
On Sat, 29 Mar 2014 17:07:20 -0400, Roy Smith wrote:
> I certainly agree that things like
>
>> if a is not b is not None: ...
>
> belong in an obfuscated coding contest.
Apart from the fact that I got it wrong (that's what happens when I post
at 6am after being up all night, thanks for the co
On Sun, Mar 30, 2014 at 12:19 PM, Tim Chase
wrote:
> On 2014-03-30 10:17, Chris Angelico wrote:
>> On Sun, Mar 30, 2014 at 9:46 AM, Tim Chase
>> wrote:
>>> Though am I correct that your iteration tests for equality, while
>>> mine tests for identity? Also, my version bails early in the
>>> event
On 2014-03-30 10:17, Chris Angelico wrote:
> On Sun, Mar 30, 2014 at 9:46 AM, Tim Chase
> wrote:
>> 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
On 03/29/2014 02:01 PM, Johannes Bauer wrote:
On 29.03.2014 20:05, Steven D'Aprano wrote:
On Sat, 29 Mar 2014 11:56:50 -0700, contact.trigon wrote:
if (a, b) != (None, None):
or
if a != None != b:
Preference? Pros? Cons? Alternatives?
if not (a is b is None): ...
Or if you prefer:
if a is
Thanks everyone; it has been very educational.
> Dave Angel:
> ...we'll find that two of the alternatives are not even equivalent.
That helped me realize (a,b) != (None, None) is not correct for the function.
It's a case where two parameters have None as the default argument. What I want
is to
On Sun, Mar 30, 2014 at 9:46 AM, Tim Chase wrote:
> 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
On 3/29/2014 2:56 PM, contact.tri...@gmail.com wrote:
if (a, b) != (None, None):
or
if a != None != b:
Preference? Pros? Cons? Alternatives?
if a is not None is not b
==
if a is not None and None is not b
==
if a is not None and b is not None
which is what I would write if not trying to be cut
In article ,
Tim Chase wrote:
> 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]):
> > >
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 ha
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)
On 2014-03-29 17:07, Roy Smith wrote:
> > if (a is not None) or (b is not None):
> >
> > is immediately understandable by everyone?
>
> I agree with that. But
>
> > if (a, b) != (None, None):
>
> seems pretty straight-forward to me too. In fact, if anything, it
> seems easier to understan
On 29.03.2014 22:55, Johannes Bauer wrote:
>>> if (a is not None) or (b is not None):
>
> Yes, probably. I liked the original, too. If I were writing the code,
> I'd probably try to aim to invert the condition though and simply do
>
> if (a is None) and (b is None)
>
> Which is pretty easy to u
On 29.03.2014 22:07, Roy Smith wrote:
> I agree with that. But
>
>> if (a, b) != (None, None):
>
> seems pretty straight-forward to me too. In fact, if anything, it seems
> easier to understand than
>
>> if (a is not None) or (b is not None):
Yes, probably. I liked the original, too. If I w
Roy Smith Wrote in message:
> In article ,
> Johannes Bauer wrote:
>
>> On 29.03.2014 20:05, Steven D'Aprano wrote:
>> > On Sat, 29 Mar 2014 11:56:50 -0700, contact.trigon wrote:
>> >
>> >> if (a, b) != (None, None):
>> >> or
>> >> if a != None != b:
>> >>
>> >> Preference? Pros? Cons? Altern
In article ,
Johannes Bauer wrote:
> On 29.03.2014 20:05, Steven D'Aprano wrote:
> > On Sat, 29 Mar 2014 11:56:50 -0700, contact.trigon wrote:
> >
> >> if (a, b) != (None, None):
> >> or
> >> if a != None != b:
> >>
> >> Preference? Pros? Cons? Alternatives?
> >
> > if not (a is b is None): ...
On 29.03.2014 20:05, Steven D'Aprano wrote:
> On Sat, 29 Mar 2014 11:56:50 -0700, contact.trigon wrote:
>
>> if (a, b) != (None, None):
>> or
>> if a != None != b:
>>
>> Preference? Pros? Cons? Alternatives?
>
> if not (a is b is None): ...
>
> Or if you prefer:
>
> if a is not b is not None: ..
> Do you actually want to check for arbitrary objects which may claim to
> equal None, or do you want to check for objects which are None?
Arbitrary objects are not a concern.
> if not (a is b is None): ...
>
> if a is not b is not None: ...
Thanks for the examples.
--
https://mail.python.o
Steven D'Aprano writes:
> if not (a is b is None): ...
>
> Or if you prefer:
>
> if a is not b is not None: ...
>>> 1 is not 1 is not None
False
So definitely the former!
ciao, lele.
--
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad ave
On Sat, 29 Mar 2014 11:56:50 -0700, contact.trigon wrote:
> if (a, b) != (None, None):
> or
> if a != None != b:
>
> Preference? Pros? Cons? Alternatives?
Do you actually want to check for arbitrary objects which may claim to
equal None, or do you want to check for objects which are None?
Nea
if (a, b) != (None, None):
or
if a != None != b:
Preference? Pros? Cons? Alternatives?
:D
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