On 3/19/2010 9:20 PM, Nick Coghlan wrote:
Glenn Linderman wrote:
The same person that would expect both
0 == 0
0.0 == 0.0
to be False... i.e. anyone that hasn't coded in Perl for too many years.
Completely different - that is comparing numbers to strings.
One can
On Fri, Mar 19, 2010 at 1:17 PM, Case Vanhorsen cas...@gmail.com wrote:
On Fri, Mar 19, 2010 at 3:07 AM, Mark Dickinson dicki...@gmail.com wrote:
On Fri, Mar 19, 2010 at 9:37 AM, Mark Dickinson dicki...@gmail.com wrote:
Making hashes of int,
float, Decimal *and* Fraction all compatible with
On Sat, Mar 20, 2010 at 12:10 AM, Greg Ewing
greg.ew...@canterbury.ac.nz wrote:
Nick Coghlan wrote:
Mark Dickinson wrote:
It seems to me that given the existing conflation of numeric equivalence
and containment testing, going the whole hog and fixing the set
membership problem for all of
On 20 March 2010 04:20, Nick Coghlan ncogh...@gmail.com wrote:
In the case of floats and Decimals, there's no ambiguity here that
creates any temptation to guess - to determine a true/false result for a
comparison, floats can be converted explicitly to Decimals without any
loss of accuracy.
On Sat, Mar 20, 2010 at 11:41 AM, Paul Moore p.f.mo...@gmail.com wrote:
On 20 March 2010 04:20, Nick Coghlan ncogh...@gmail.com wrote:
In the case of floats and Decimals, there's no ambiguity here that
creates any temptation to guess - to determine a true/false result for a
comparison, floats
Michael Foord a écrit :
On 19/03/2010 18:58, Pascal Chambon wrote:
Hello
I've already crossed a bunch of articles detailing python's attribute
lookup semantic (__dict__, descriptors, order of base class
traversing...), but I have never seen, so far, an explanation of
WHICH method did waht,
Mark Dickinson dickinsm at gmail.com writes:
On Fri, Mar 19, 2010 at 9:50 PM, Guido van Rossum guido at python.org
wrote:
There is one choice which I'm not sure about. Should a mixed
float/Decimal operation return a float or a Decimal?
I'll just say that it's much easier to return a
On Sat, Mar 20, 2010 at 4:06 AM, Mark Dickinson dicki...@gmail.com wrote:
On Fri, Mar 19, 2010 at 1:17 PM, Case Vanhorsen cas...@gmail.com wrote:
On Fri, Mar 19, 2010 at 3:07 AM, Mark Dickinson dicki...@gmail.com wrote:
On Fri, Mar 19, 2010 at 9:37 AM, Mark Dickinson dicki...@gmail.com wrote:
On Fri, 19 Mar 2010 23:20:52 -0400, Alexander Belopolsky
alexander.belopol...@gmail.com wrote:
I will not go into details here beyond referring to
http://bugs.python.org/issue8154, but if you follow the link, you'll
see that there was not a consensus on how the issue should be
addressed and
On 3/20/2010 7:06 AM, Mark Dickinson wrote:
Will this change the result of hashing a long? I know that both gmpy
and SAGE use their own hash implementations for performance reasons. I
understand that CPython's hash function is an implementation detail,
but there are external modules that rely
Sean Reifschneider jafo at tummy.com writes:
I would propose changing the Python syslog() call to do the C equivalent of:
if openlog_hasnt_been_called_before_now:
if sys.argv[0]:
syslog.openlog(os.path.basename(sys.argv[0]))
In other words, if there's a script name and
I did not receive the usual Friday tracker post on issues opened and
closed during the past week.
Did anyone else?
I am reading via gmane.
Terry Jan Reedy
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On Sat, Mar 20, 2010 at 09:11, Antoine Pitrou solip...@pitrou.net wrote:
Mark Dickinson dickinsm at gmail.com writes:
On Fri, Mar 19, 2010 at 9:50 PM, Guido van Rossum guido at python.org
wrote:
There is one choice which I'm not sure about. Should a mixed
float/Decimal operation return a
On Sat, Mar 20, 2010 at 3:17 PM, Case Vanhorsen cas...@gmail.com wrote:
On Sat, Mar 20, 2010 at 4:06 AM, Mark Dickinson dicki...@gmail.com wrote:
What external modules are there that rely on existing hash behaviour?
I'm only aware of gmpy and SAGE.
And exactly what behaviour do they rely
On Sat, Mar 20, 2010 at 11:02, Terry Reedy tjre...@udel.edu wrote:
I did not receive the usual Friday tracker post on issues opened and closed
during the past week.
Did anyone else?
I am reading via gmane.
Terry Jan Reedy
I actually haven't seen that mail in a few weeks (subscribed to the
On Sat, Mar 20, 2010 at 10:05 AM, Mark Dickinson dicki...@gmail.com wrote:
On Sat, Mar 20, 2010 at 3:17 PM, Case Vanhorsen cas...@gmail.com wrote:
On Sat, Mar 20, 2010 at 4:06 AM, Mark Dickinson dicki...@gmail.com wrote:
What external modules are there that rely on existing hash behaviour?
On Sat, 20 Mar 2010 11:11:17 -0600, Brian Curtin brian.cur...@gmail.com wrote:
On Sat, Mar 20, 2010 at 11:02, Terry Reedy tjre...@udel.edu wrote:
I did not receive the usual Friday tracker post on issues opened and closed
during the past week.
Did anyone else?
I am reading via gmane.
On Sat, Mar 20, 2010 at 4:58 AM, Mark Dickinson dicki...@gmail.com wrote:
On Sat, Mar 20, 2010 at 11:41 AM, Paul Moore p.f.mo...@gmail.com wrote:
On 20 March 2010 04:20, Nick Coghlan ncogh...@gmail.com wrote:
In the case of floats and Decimals, there's no ambiguity here that
creates any
Darn. I bet I broke it when I added the 'languishing' status. I even
thought about that at the time but didn't follow up on it. I'll see
if I can figure out where the script lives.
My guess is that the Debian upgrade killed it.
Regards,
Martin
On Sat, Mar 20, 2010 at 4:16 AM, Mark Dickinson dicki...@gmail.com wrote:
True. The reason I was concentrating on the hashes is that it's not
immediately obvious that it's even *possible* to find a decent hash
function that's efficient to compute and gives equal results for
numerically equal
On Sat, Mar 20, 2010 at 7:56 PM, Guido van Rossum gu...@python.org wrote:
I propose to reduce all hashes to the hash of a normalized fraction,
which we can define as a combination of the hashes for the numerator
and the denominator. Then all we have to do is figure fairly efficient
ways to
On Sat, Mar 6, 2010 at 12:43, Brett Cannon br...@python.org wrote:
I see two possible fixes for this. One is to not silence DeprecationWarning
if Py_DivisionWarningFlag is set to = 1. The other is to introduce a new
subclass of DeprecationWarning called IntegerDivisionWarning and have that
Glenn Linderman wrote:
One can argue that either way, that it is completely different, or
completely the same.
An important difference is that there is no intermediate type
that can be compared with both ints and strings.
Another relevant difference is that numbers are just one of
many
Adam Olsen wrote:
For a little context, we have this numeric tower:
int - Fraction - float - complex
Decimal is more precise, and pays a performance cost for it. It also
seems odd to stick it between float and complex (nobody's planning a
ComplexDecimal, right?) That suggests it should go
On Sat, Mar 20, 2010 at 4:20 PM, Greg Ewing greg.ew...@canterbury.ac.nz wrote:
Adam Olsen wrote:
For a little context, we have this numeric tower:
int - Fraction - float - complex
Decimal is more precise, and pays a performance cost for it. It also
seems odd to stick it between float and
On Sat, Mar 20, 2010 at 11:20 PM, Greg Ewing
greg.ew...@canterbury.ac.nz wrote:
* Decimal and float really belong side-by-side in the
tower, rather than one above the other. Neither of them is
inherently any more precise or exact than the other.
Except that float is fixed-width (typically 53
On Sat, Mar 20, 2010 at 4:46 PM, Mark Dickinson dicki...@gmail.com wrote:
On Sat, Mar 20, 2010 at 11:20 PM, Greg Ewing
greg.ew...@canterbury.ac.nz wrote:
* Decimal and float really belong side-by-side in the
tower, rather than one above the other. Neither of them is
inherently any more
On Sat, Mar 20, 2010 at 17:20, Greg Ewing greg.ew...@canterbury.ac.nz wrote:
There are two ways in which that linear tower is overly
simplistic:
* It conflates the notions of exactness and width. They're
really orthogonal concepts, and to reflect this you would
need two parallel towers, with
Greg Ewing wrote:
Antoine Pitrou wrote:
We forbid comparisons when there is a real danger or ambiguity, such
as unicode
vs. bytes. There is no such danger or ambiguity when comparing a
decimal with a
float.
So do you think that float(0.1) and Decimal(0.1) should be
equal or not, and
Glenn Linderman wrote:
Thanks, though for the nice chart from an internals guy, you confirmed
all that I thought I knew about how this presently works, from PEP and
manual reading, a bit of experimentation, and the discussions here.
I'll confess to a bit of interpreter prompt experimentation
On 20/03/2010 12:00, Pascal Chambon wrote:
Michael Foord a écrit :
On 19/03/2010 18:58, Pascal Chambon wrote:
Hello
I've already crossed a bunch of articles detailing python's
attribute lookup semantic (__dict__, descriptors, order of base
class traversing...), but I have never seen, so
Guido van Rossum wrote:
I think we should seriously reconsider allowing mixed arithmetic
involving Decimal, not just mixed comparisons.
I'm glad I'm not the only one that started wondering that. I
wasn't quite game enough to actually suggest it though :)
There is one choice which I'm not
Michael Foord wrote:
Well, the documentation you pointed to specifies that __getattr__ will
be called if __getattribute__ raises an AttributeError, it just doesn't
specify that it is done by object.__getattribute__ (which it isn't).
And as for why not: because __getattribute__ implementations
On Mar 20, 2010, at 6:54 PM, Nick Coghlan wrote:
I suggest a 'linearised' numeric tower that looks like:
int - Decimal - Fraction - float - complex
Is that a typo? Shouldn't Decimal and float go between Fraction and complex?
The abstract numeric tower is:
Number Complex Real
On Mar 20, 2010, at 4:27 PM, Jeffrey Yasskin wrote:
When designing it, I tried to include a notion of exact/inexact types,
but we couldn't find anything practical to do with them, so we took
them out.
The were also other reasons that they were taken out. The notion of
inexactness is a
Mark Dickinson wrote:
Except that float is fixed-width (typically 53 bits of precision),
while Decimal allows a user-specified, arbitrarily large, precision;
Yes, but it still has *some* fixed limit at any given
moment, so the result of an operation on Decimals always
has the potential to
Nick Coghlan wrote:
Note that Antoine's point was that float(0.1) and
Decimal.from_float(0.1) should compare equal.
That would mean that Decimal(0.1) != float(0.1), which might be
surprising to someone who didn't realise they were mixing floats
and decimals.
--
Greg
Michael Foord wrote:
Well, the documentation you pointed to specifies that __getattr__ will
be called if __getattribute__ raises an AttributeError, it just doesn't
specify that it is done by object.__getattribute__ (which it isn't).
If __getattribute__ raises an exception, it won't get a
Nick Coghlan wrote:
int - Decimal - Fraction - float - complex
I don't think it's a good idea to put Decimal below Fraction,
because Decimal has to be considered an implicitly inexact
type like float, and we don't want to coerce from an inexact
type to an exact one.
--
Greg
On Sat, Mar 20, 2010 at 22:48, Greg Ewing greg.ew...@canterbury.ac.nz wrote:
Nick Coghlan wrote:
Note that Antoine's point was that float(0.1) and
Decimal.from_float(0.1) should compare equal.
That would mean that Decimal(0.1) != float(0.1), which might be
surprising to someone who didn't
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