Le Tuesday 11 November 2008 15:21:03 M.-A. Lemburg, vous avez écrit :
> Because None is already special, has had this feature for a very
> long time (...)
Yeah, Python3 breaks compatibility by removing old dummy behaviour like
comparaison between bytes and characters, or between an integer an Non
We're not going to add the "feature" back that None compares smaller
than everything. It's a slippery slope that ends with all operations
involving None returning None -- I've seen a proposal made in all
earnestness requesting that None+42 == None, None() == None, and so
on. This Nonesense was wise
M.-A. Lemburg wrote:
Why was the special case for None being "smaller" than all other
objects in Python removed from Python 3.0 ? (see object.c in Py2.x)
For one thing, it is only smallest when it controls the comparison.
>>> class c(object):
... def __lt__(s,o): return True
...
>>> cc = c()
[M.-A. Lemburg]
> ...
> That's fine. I'm just talking about the special case for None that
> has existed in Python for years - and for a good reason.
That's overstating it a bit ;-) In Python 1.5.1, comparisons were
changed so that objects of numeric types compared smaller than objects
of non-num
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On Nov 11, 2008, at 8:54 AM, M.-A. Lemburg wrote:
On 2008-11-11 14:28, Antoine Pitrou wrote:
M.-A. Lemburg egenix.com> writes:
Why was the special case for None being "smaller" than all other
objects in Python removed from Python 3.0 ? (see objec
On 2008-11-11 18:09, Guido van Rossum wrote:
> We're not going to add the "feature" back that None compares smaller
> than everything. It's a slippery slope that ends with all operations
> involving None returning None -- I've seen a proposal made in all
> earnestness requesting that None+42 == Non
>> What it does is that it injects the classes defined in this particular
>> module to the other modules. First problem: 2to3 tool doesn't convert
>> this correctly, I had to manually conver this
>> to:
>
> Would you file a bug report for the 2to3 problem, please? That should be
> fixed.
I will.
M.-A. Lemburg egenix.com> writes:
>
> NULLs are a fact in life, not only in SQL, but also in numerics and
> statistics. You often don't want a complex calculation or query to
> fail just because a few input values are not available.
But it only works in the case where you only do comparisons, an
On 2008-11-11 14:28, Antoine Pitrou wrote:
> M.-A. Lemburg egenix.com> writes:
>> Why was the special case for None being "smaller" than all other
>> objects in Python removed from Python 3.0 ? (see object.c in Py2.x)
>
> Because ordered comparisons (<, <=, >, >=) are much stricter in 3.0 than in
On 2008-11-11 15:07, Barry Warsaw wrote:
> On Nov 11, 2008, at 8:54 AM, M.-A. Lemburg wrote:
>
>> On 2008-11-11 14:28, Antoine Pitrou wrote:
>>> M.-A. Lemburg egenix.com> writes:
Why was the special case for None being "smaller" than all other
objects in Python removed from Python 3.0 ?
On 2008-11-11 15:22, Daniel Stutzbach wrote:
> On Tue, Nov 11, 2008 at 7:06 AM, M.-A. Lemburg <[EMAIL PROTECTED]> wrote:
>
>> Why was the special case for None being "smaller" than all other
>> objects in Python removed from Python 3.0 ? (see object.c in Py2.x)
>>
>
> It wasn't true in Python 2.5
M.-A. Lemburg egenix.com> writes:
>
> Why was the special case for None being "smaller" than all other
> objects in Python removed from Python 3.0 ? (see object.c in Py2.x)
Because ordered comparisons (<, <=, >, >=) are much stricter in 3.0 than in 2.x.
In practice, ordered comparisons which do
M.-A. Lemburg wrote:
And here's another one:
...
Two values that compare equal to each other (and are in fact identical),
yet cannot be compared less-than or greater-than.
That's not particularly surprising -- complex numbers have
been like that for a long time. The only surprise, if any,
is t
Why was the special case for None being "smaller" than all other
objects in Python removed from Python 3.0 ? (see object.c in Py2.x)
There's currently a discussion on c.l.p regarding this issue (see below).
It looks like a bug in Python 3.0 to me, since None is widely used as
"n/a" object in Pyth
M.-A. Lemburg egenix.com> writes:
>
> >>> None > None
> Traceback (most recent call last):
> File "", line 1, in
> TypeError: unorderable types: NoneType() > NoneType()
> >>> None != None
> False
>
> Two values that compare equal to each other (and are in fact identical),
> yet cannot be comp
M.-A. Lemburg wrote:
On 2008-11-11 14:28, Antoine Pitrou wrote:
But why should "n/a" (or "missing", or "undefined") imply "smaller than
everything else"?
It's just a convention based on viewing None as "nothing" or the
empty set.
It would be possible to implement this convention in the
sort
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