Re: Help with changes in traceback stack from Python 2.7 to Python 3.x
On Mon, 28 Apr 2014 12:19:02 +1000, Chris Angelico wrote: > On Mon, Apr 28, 2014 at 12:11 PM, Steven D'Aprano > wrote: >> Suppose we could pass variables directly to the constructor, like this: >> >> a = b = 2 >> L = [1, 2, 3] >> dctA = dict(a, b, L[1], 2, 1+1) >> >> Obviously all five values are 2, but what are the keys? >> >> The dict construct >> receives five arguments, all bound to the object 2. (That might be the >> same object five times, or five distinct objects, all with the same >> value of 2.) > > Just to nit-pick: A conforming Python implementation might pass up to > four distinct objects, but the first two MUST be the same object. :) So it does, thanks for the correction. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: Unicode in Python
Le samedi 26 avril 2014 15:38:29 UTC+2, Ian a écrit : > On Apr 26, 2014 3:46 AM, "Frank Millman" wrote: > > > > > > > > > wrote in message > > > news:03bb12d8-93be-4ef6-94ae-4a02789ae...@googlegroups.com... > > > > == > > > > > > > > I wrote once 90 % of Python 2 apps (a generic term) supposed to > > > > process text, strings are not working. > > > > > > > > In Python 3, that's 100 %. It is somehow only by chance, apps may > > > > give the illusion they are properly working. > > > > > > > > > > It is quite frustrating when you make these statements without explaining > > > what you mean by 'not working'. > > As far as anybody has been able to determine, what jmf means by "not working" > is that strings containing the EURO character are handled less efficiently > than strings that do not contain it in certain contrived test cases. Python 2.7 + cp1252: - Solid and coherent system (nothing to do with the Euro). Python 3: - It missed the unicode shift. - Covering the whole unicode range will not make Python a unicode compliant product. - Flexible String Representation (a problem per se), a mathematical absurditiy which does the opposite of the coding schemes endorsed by Unicord.org (sheet of paper and pencil!) - Very deeply buggy (quadrature of the circle problem). Positive side: - A very nice tool to teach the coding of characters and unicode. jmf -- https://mail.python.org/mailman/listinfo/python-list
Re: possible bug in re expression?
On 25/04/2014 19:32, Terry Reedy wrote:
..
I suppose that one could argue that '{' alone should be treated as special
immediately, and not just when a matching '}' is found, and should disable other
special meanings. I wonder what JS does if there is no matching '}'?
well in fact I suspect this is my mistranslation of the original
new RegExp('.{1,' + (+size) + '}', 'g')
my hacked up translator doesn't know what that means. I suspect that (+size) is
an attempt to force size to an integer prior to it being forced to a string. I
used to believe that conversion was always written 0-x, but experimentally
(+"3") ends up as 3 not "3".
Naively, I imagined that re would complain about ambiguous regular expressions,
but in the regexp world n problems --> n+1 problems almost surely so I should
have anticipated it :)
Does this in fact that almost any broken regexp specification will silently fail
because re will reset and consider any metacharacter as literal?
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Re: Inconsistent viewkeys behaviour
On 4/28/2014 2:22 AM, Joshua Landau wrote: Is there any reference for this strange behaviour on Python 2: >>> set() < dict().viewkeys() Traceback (most recent call last): File "", line 1, in TypeError: can only compare to a set >>> dict().viewkeys() > set() False The left operand determines the result. The manual specifies that < and > do not have to be consistent. But I suspect that when 3.x dict.keys() was backported to 2.7.0, no one thought to update set, whereas the backported key view code already had the comparison. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: Proper deletion of selected items during map iteration in for loop: Thanks to all
Chris Angelico wrote: > # Snapshot of keys: > for k in list(d): > if f(k): del d[k] > > No extra loop at the end, no switching out and in of contents, just > one little change in the loop header. Obviously you don't want to do > this when you're deleting two out of three billion, but for smallish > dicts, that won't make a visible change. Even if you have three billion keys, the extra memory needed to create a list that references those keys is going to be a lot less than the memory used by the keys themselves. For example if the keys are 6 character strings then each string needs I think at least 45 bytes (64 bit Python 2.x, up to double that in Python 3.x) but the list only needs one 8 byte pointer per key. I would always choose this simple solution until such time as it is proved to be a problem. -- Duncan Booth -- https://mail.python.org/mailman/listinfo/python-list
Re: possible bug in re expression?
On Mon, 28 Apr 2014 10:47:54 +0100, Robin Becker wrote:
> Does this in fact that almost any broken regexp specification will
> silently fail because re will reset and consider any metacharacter as
> literal?
Well, I don't know about "almost any", but at least some broken regexes
will explicitly fail:
py> import re
py> re.search('*', "123*4")
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python3.3/re.py", line 161, in search
return _compile(pattern, flags).search(string)
[...]
File "/usr/local/lib/python3.3/sre_parse.py", line 552, in _parse
raise error("nothing to repeat")
sre_constants.error: nothing to repeat
(For brevity I have abbreviated the traceback.)
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http://import-that.dreamwidth.org/
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problem with regex
i want to find a specific urls from a txt file but i have some issus. First
when i take just two lines from the file with copy paste and assign it to a
variable like this and it works only with triple quotes
test='''_*_n.jpg","timelineCoverPhoto":"{\"focus\":{\"x\":0.5,\"y\":0.386925795053},\"photo\":{\"__type__\":{\"name\":\"Photo\"},\"image_lowres\":{\"uri\":\"https://fbcdn-photos-f-a.akamaihd.net/*-*-*/*_*_*_a.jpg\",\"width\":180,\"height\":179}}}","subscribeStatus":"IS_SUBSCRIBED","smallPictureUrl":"https://fbcdn-profile-a.akamaihd.net/*-*-*/s100x100/*_*_*_s.jpg","contactId":"*==","contactType":"USER","friendshipStatus":"ARE_FRIENDS","graphApiWriteId":"contact_*:*:*","hugePictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-frc3/*_*_*_n.jpg","profileFbid":"1284503586","isMobilePushable":"NO","lookupKey":null,"name":{"displayName":"*
*","firstName":"*","lastName":"*"},"nameSearchTokens":["*","*"],"phones":[],"phoneticName":{"displayName":null,"firstName":null,"lastName":null},"isMemorialized":false,"communicationRank":1.1144714,"canViewerSendGift":false,"canMessage":true}
*=={"bigPictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash3/*.*.*.*/s200x200/*_*_*_n.jpg","timelineCoverPhoto":"{\"focus\":{\"x\":0.5,\"y\":0.49137931034483},\"photo\":{\"__type__\":{\"name\":\"Photo\"},\"image_lowres\":{\"uri\":\"https://fbcdn-photos-h-a.akamaihd.net/*-*-*/*_*_*_a.jpg\",\"width\":180,\"height\":135}}}","subscribeStatus":"IS_SUBSCRIBED","smallPictureUrl":"https://fbcdn-profile-a.akamaihd.net/*-*-*/*.*.*.*/s100x100/*_*_*_a.jpg","contactId":"*==","contactType":"USER","friendshipStatus":"ARE_FRIENDS","graphApiWriteId":"contact_*:*:*","hugePictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash3/c0.0.540.540/*_*_*_n.jpg","profileFbid":"*","isMobilePushable":"YES","lookupKey":null,"name":{"displayName":"*
*","firstName":"*","lastName":"*"},"nameSearchTokens":["*","*"],"phones":[],"phoneticName":{"displayName":null,"firstName":null,"lastName":null},"isMemorialized":false,"communicationRank":1.2158813,"canViewerSendGift":false,"canMessage":true}'''
uri = re.findall(r'''uri\":\"https://fbcdn-(a-z|photos)?([^\'" >]+)''',test)
print uri
it works fine and i have my result [('photos',
'-f-a.akamaihd.net/*-*-*/*_*_*_a.jpg'), ('photos',
'-h-a.akamaihd.net/*-*-*/*_*_*_a.jpg')]
but if a take those lines and save it into a txt file like the original is
without the quotes and do the following
datafile=open('a.txt','r')
data_array=''
for line in datafile:
data_array=data_array+line
uri = re.findall(r'''uri\":\"https://fbcdn-(a-z|photos)?([^\'"
>]+)''',data_array)
after printing uri it gives an empty list,. what to do to make it work for the
lines of a txt file
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problem with regex
i want to find a specific urls from a txt file but i have some issus. First
when i take just two lines from the file with copy paste and assign it to a
variable like this and it works only with triple quotes
test='''_*_n.jpg","timelineCoverPhoto":"{\"focus\":{\"x\":0.5,\"y\":0.386925795053},\"photo\":{\"__type__\":{\"name\":\"Photo\"},\"image_lowres\":{\"uri\":\"https://fbcdn-photos-f-a.akamaihd.net/*-*-*/*_*_*_a.jpg\",\"width\":180,\"height\":179}}}","subscribeStatus":"IS_SUBSCRIBED","smallPictureUrl":"https://fbcdn-profile-a.akamaihd.net/*-*-*/s100x100/*_*_*_s.jpg","contactId":"*==","contactType":"USER","friendshipStatus":"ARE_FRIENDS","graphApiWriteId":"contact_*:*:*","hugePictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-frc3/*_*_*_n.jpg","profileFbid":"*","isMobilePushable":"NO","lookupKey":null,"name":{"displayName":"*
*","firstName":"*","lastName":"*"},"nameSearchTokens":["*","*"],"phones":[],"phoneticName":{"displayName":null,"firstName":null,"lastName":null},"isMemorialized":false,"communicationRank":1.1144714,"canViewerSendGift":false,"canMessage":true}
*=={"bigPictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash3/*.*.*.*/s200x200/*_*_*_n.jpg","timelineCoverPhoto":"{\"focus\":{\"x\":0.5,\"y\":0.49137931034483},\"photo\":{\"__type__\":{\"name\":\"Photo\"},\"image_lowres\":{\"uri\":\"https://fbcdn-photos-h-a.akamaihd.net/*-*-*/*_*_*_a.jpg\",\"width\":180,\"height\":135}}}","subscribeStatus":"IS_SUBSCRIBED","smallPictureUrl":"https://fbcdn-profile-a.akamaihd.net/*-*-*/*.*.*.*/s100x100/*_*_*_a.jpg","contactId":"*==","contactType":"USER","friendshipStatus":"ARE_FRIENDS","graphApiWriteId":"contact_*:*:*","hugePictureUrl":"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash3/c0.0.540.540/*_*_*_n.jpg","profileFbid":"*","isMobilePushable":"YES","lookupKey":null,"name":{"displayName":"*
*","firstName":"*","lastName":"*"},"nameSearchTokens":["*","*"],"phones":[],"phoneticName":{"displayName":null,"firstName":null,"lastName":null},"isMemorialized":false,"communicationRank":1.2158813,"canViewerSendGift":false,"canMessage":true}'''
uri = re.findall(r'''uri\":\"https://fbcdn-(a-z|photos)?([^\'" >]+)''',test)
print uri
it works fine and i have my result [('photos',
'-f-a.akamaihd.net/*-*-*/*_*_*_a.jpg'), ('photos',
'-h-a.akamaihd.net/*-*-*/*_*_*_a.jpg')]
but if a take those lines and save it into a txt file like the original is
without the quotes and do the following
datafile=open('a.txt','r')
data_array=''
for line in datafile:
data_array=data_array+line
uri = re.findall(r'''uri\":\"https://fbcdn-(a-z|photos)?([^\'"
>]+)''',data_array)
after printing uri it gives an empty list,. what to do to make it work for the
lines of a txt file
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Re: problem with regex
In article ,
dimm...@gmail.com wrote:
> i want to find a specific urls from a txt file but i have some issus. First
> when i take just two lines from the file with copy paste and assign it to a
> variable like this and it works only with triple quotes
>
> test=''
[...]
> but if a take those lines and save it into a txt file like the original is
> without the quotes [it doesn't work]
I suspect this has nothing to do with regular expressions, but it's just
about string management.
The first thing you want to do is verify that the text you are reading
in from the file is the same as the text you have in triple quotes. So,
write a program like this:
test=''
datafile=open('a.txt','r')
data_array=''
for line in datafile:
data_array=data_array+line
print test == data_array
If that prints True, then you've got the same text in both cases (and
you can go on to looking for other problems). I suspect it will print
False, though. So, now your task is to figure out where those two
strings differ. Maybe something like:
for c1, c2 in zip(test, data_array):
print c1 == c2, repr(c1), repr(c2)
and look for the first place they're not the same. Hopefully that will
give you a clue what's going wrong.
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Convert numpy array to single number
I have a numpy array consisting of 1s and zeros for representing binary numbers: e.g. >>> binary array([ 1., 0., 1., 0.]) I wish the array to be in the form 1010, so it can be manipulated. I do not want to use built in binary converters as I am trying to build my own. -- https://mail.python.org/mailman/listinfo/python-list
Re: possible bug in re expression?
On 28/04/2014 12:49, Steven D'Aprano wrote: .. Well, I don't know about "almost any", but at least some broken regexes will explicitly fail: py> import re sre_constants.error: nothing to repeat (For brevity I have abbreviated the traceback.) so there is intent to catch some specification errors. I've abandoned this translation anyhow as all that was intended was to split the string into non-overlapping strings of size at most k. I find this works faster than the regexp even if the regexp is pre-compiled. [p[i:i+k] for i in xrange(0,len(p),k)] -- Robin Becker -- https://mail.python.org/mailman/listinfo/python-list
Re: Convert numpy array to single number
On Mon, 28 Apr 2014 06:04:02 -0700, mboyd02255 wrote: > I have a numpy array consisting of 1s and zeros for representing binary > numbers: > > e.g. > > >>> binary > array([ 1., 0., 1., 0.]) > > I wish the array to be in the form 1010, so it can be manipulated. > > I do not want to use built in binary converters as I am trying to build > my own. Did you have a question, or are you just sharing? -- Steven D'Aprano http://import-that.dreamwidth.org/ -- https://mail.python.org/mailman/listinfo/python-list
Significant digits in a float?
I'm using Python 2.7
I have a bunch of floating point values. For example, here's a few (printed as
reprs):
38.0
41.2586
40.752801
49.25
33.7951994
36.8371996
34.1489
45.5
Fundamentally, these numbers have between 0 and 4 decimal digits of precision,
and I want to be able to intuit how many each has, ignoring the obvious
floating point roundoff problems. Thus, I want to map:
38.0 ==> 0
41.2586 ==> 4
40.752801 ==> 4
49.25 ==> 2
33.7951994 ==> 4
36.8371996 ==> 4
34.1489 ==> 4
45.5 ==> 1
Is there any clean way to do that? The best I've come up with so far is to
str() them and parse the remaining string to see how many digits it put after
the decimal point.
The numbers are given to me as Python floats; I have no control over that. I'm
willing to accept that fact that I won't be able to differentiate between
float("38.0") and float("38."). Both of those map to 1, which is OK for my
purposes.
---
Roy Smith
r...@panix.com
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Re: Significant digits in a float?
On 4/28/14 12:00 PM, Roy Smith wrote:
Fundamentally, these numbers have between 0 and 4 decimal digits of precision,
and I want to be able to intuit how many each has, ignoring the obvious
floating point roundoff problems. Thus, I want to map:
38.0 ==> 0
41.2586 ==> 4
40.752801 ==> 4
49.25 ==> 2
33.7951994 ==> 4
36.8371996 ==> 4
34.1489 ==> 4
45.5 ==> 1
Is there any clean way to do that? The best I've come up with so far is to
str() them and parse the remaining string to see how many digits it put after
the decimal point.
That sounds like a pretty clean way: len(str(num).partition(".")[2]),
though it also sounds like you understand all of the inaccuracies in
that technique.
--
Ned Batchelder, http://nedbatchelder.com
--
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Re: Significant digits in a float?
On Tue, Apr 29, 2014 at 2:00 AM, Roy Smith wrote: > I have a bunch of floating point values. For example, here's a few (printed > as reprs): > > 38.0 > 41.2586 > 40.752801 > 49.25 > 33.7951994 > 36.8371996 > 34.1489 > 45.5 > > Fundamentally, these numbers have between 0 and 4 decimal digits of > precision... Terminology question: Why do you count only what's after the decimal point? I would describe these as having between 2 and 6 significant figures. Will they always have two digits before the decimal, or does your precision really care only about what's after it? Of course, there would still remain the problem of describing 49.25 with 6 sig figs, in the same way that it's hard to explain to someone that you really do need to leave in five minutes (but if you said you had to leave in six minutes, they'd believe you to be accurate to the minute). But I assume that's not part of the question. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Heartbleed and the windows distributions on python.org
I am building a cherrypy app that is testing as vulnerable to the heartbleed exploit. The app is running on the 64 bit 3.3.5 Windows distribution of python. An updated version of 64 bit Python 3.3.x for Windows or an updated pyopenssl? I am kind of surprised the distribution on python.org hasen't been updated. Here is the thread on the issue from the cherrypy-users group. -- https://mail.python.org/mailman/listinfo/python-list
Re: Significant digits in a float?
On Monday, April 28, 2014 12:28:59 PM UTC-4, Chris Angelico wrote: > Terminology question: Why do you count only what's after the decimal > point? I would describe these as having between 2 and 6 significant > figures. Will they always have two digits before the decimal, or does > your precision really care only about what's after it? Hmmm, yeah, I was being sloppy in my description. Definitely would have gotten points off in physics class for being so sloppy :-) No, there's not always two digits before the decimal. Could be anywhere from 0 to 3 digits before. What I'm really after is how many digits are after the decimal point. -- https://mail.python.org/mailman/listinfo/python-list
Re: Significant digits in a float?
On Monday, April 28, 2014 12:07:14 PM UTC-4, Ned Batchelder wrote:
> On 4/28/14 12:00 PM, Roy Smith wrote:
>> 38.0 ==> 0
>> [...]
>> Is there any clean way to do that? The best I've come up with so far is to
>> str() them and parse the
>> remaining string to see how many digits it put after the decimal point.
>
> That sounds like a pretty clean way: len(str(num).partition(".")[2]),
> though it also sounds like you understand all of the inaccuracies in
Well, it's actually, a little uglier, because I want to map 38.0 ==>0, so I
need to special case that.
The other annoying thing about using str() is its behavior isn't well defined.
It looks like it does the right thing, but I imagine the details could change
in a different implementation.
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Re: Significant digits in a float?
On 4/28/14 2:39 PM, Roy Smith wrote:
On Monday, April 28, 2014 12:07:14 PM UTC-4, Ned Batchelder wrote:
On 4/28/14 12:00 PM, Roy Smith wrote:
38.0 ==> 0
[...]
Is there any clean way to do that? The best I've come up with so far is to
str() them and parse the
remaining string to see how many digits it put after the decimal point.
That sounds like a pretty clean way: len(str(num).partition(".")[2]),
though it also sounds like you understand all of the inaccuracies in
Well, it's actually, a little uglier, because I want to map 38.0 ==>0, so I
need to special case that.
Ah, right.
The other annoying thing about using str() is its behavior isn't well defined.
It looks like it does the right thing, but I imagine the details could change
in a different implementation.
I don't have a reference, but in recent Pythons, str() was specifically
changed to guarantee that it produces the shortest string that when
re-interpreted as a float, produces the same float.
--
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Re:Significant digits in a float?
Roy Smith Wrote in message:
> I'm using Python 2.7
>
> I have a bunch of floating point values. For example, here's a few (printed
> as reprs):
>
> 38.0
> 41.2586
> 40.752801
> 49.25
> 33.7951994
> 36.8371996
> 34.1489
> 45.5
>
> Fundamentally, these numbers have between 0 and 4 decimal digits of
> precision, and I want to be able to intuit how many each has, ignoring the
> obvious floating point roundoff problems. Thus, I want to map:
>
> 38.0 ==> 0
> 41.2586 ==> 4
> 40.752801 ==> 4
> 49.25 ==> 2
> 33.7951994 ==> 4
> 36.8371996 ==> 4
> 34.1489 ==> 4
> 45.5 ==> 1
>
> Is there any clean way to do that? The best I've come up with so far is to
> str() them and parse the remaining string to see how many digits it put after
> the decimal point.
>
> The numbers are given to me as Python floats; I have no control over that.
> I'm willing to accept that fact that I won't be able to differentiate between
> float("38.0") and float("38."). Both of those map to 1, which is OK for
> my purposes.
>
Ignoring the unexpected terminology, you seem to be looking for
the number of decimal places, and you're not interested in 2100
==> -2
If you know something about the possible range of the numbers,
and/or you know the valid range of decimal places, then you
should convert to string in a way that will round the 3rd, 5th,
and 6th values. Then if the string has no decimal, the answer is
0. If there are any trailing zeroes, strip them. Then just count
digits after the decimal point.
Without such limits, there can be no unique algorithm, and thus
no correct code.
--
DaveA
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Re: Heartbleed and the windows distributions on python.org
In article , Timothy McDonald wrote: > I am building a cherrypy app that is testing as vulnerable to the heartbleed > exploit. The app is running on the 64 bit 3.3.5 Windows distribution of > python. An updated version of 64 bit Python 3.3.x for Windows or an updated > pyopenssl? I am kind of surprised the distribution on python.org hasen't been > updated. The current release of Python 3 is 3.4.0. A 3.4.1 maintenance release, with OpenSSL updated in the Windows installer, is planned for final release in mid-May. Python 3.3.x is now in security-fix-only mode which means only source fixes for security problems are released as needed and no further binary installers for Windows or OS X are produced. (The Python 2 Windows installer is not affected since it bundles an older, pre-heartbleed version of OpenSSL.) -- Ned Deily, n...@acm.org -- https://mail.python.org/mailman/listinfo/python-list
Re:Convert numpy array to single number
mboyd02...@gmail.com Wrote in message: > I have a numpy array consisting of 1s and zeros for representing binary > numbers: > > e.g. > > >>> binary > array([ 1., 0., 1., 0.]) > > I wish the array to be in the form 1010, so it can be manipulated. > > I do not want to use built in binary converters as I am trying to build my > own. > One thousand and ten is an int, not an array. So is 10, but it seems a more likely value you might be trying for. As for using the builtin binary converters, you'd better be a lot more specific, as you cannot even print an int in decimal form without utilizing them. The number is in binary already. Please copy the exact problem and constraints, as well as what you've written so far and what's wrong with it. -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
Re:problem with regex
dimm...@gmail.com Wrote in message:
> i want to find a specific urls from a txt file but i have some issus. First
> when i take just two lines from the file with copy paste and assign it to a
> variable like this and it works only with triple quotes
>
> test='''_*_n.jpg","timelineCoverPhoto":"{\"focus\":{\"x\":0.5,\"y\":0.386925795053},\"photo\":{\"__type__\":{\"name\":\"Photo\"},\"image_lowres\":{\"uri\":\"https://fbcdn-photos-f-a.akamaihd.net/*-*-*
Why did you start a second thread with similar content two minutes
after the first? Do you expect us to compare the two messages and
figure out what you changed, or were you just impatient for a
response? I only check in here about 6 times a day, and I
imagine some might be even less often.
Your test string literal has lots of backslashes in it, which get
interpreted into escape sequences in a literal, but not in a
file. If that's really what the file looks like, you're going
to want to use a raw string. I agree with Roy, you're probably
not getting the same string the two ways.
--
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Re: Help with changes in traceback stack from Python 2.7 to Python 3.x
On 4/27/14 5:51 PM, Andrew Konstantaras wrote: I guess I am missing something big as I am looking for a shorthand way of doing the following: dctA = dict(x=x, y=y, ... n=n) Yes, your makeDict(x, y) is a shorthand for dict(x=x, y=y), but there are many things you can do with dict that you can't do with makeDict. What is the makeDict equivalent of: dict(x=12, y=self.y, z=a+b) The code you have allows you more compact expression, but it brings fragility and surprise. This is, as I understand it a very natural way of using a dictionary. It seems that this syntax is unnecessarily redundant and hence my goal of writing something more compact. Perhaps the way I am doing it is a little unorthodox, but the ultimate use of a dictionary is, as I understand it, completely in line with how dictionaries were designed to be used. In my other code, I often use these dictionaries to pass arguments to functions and return results. It allows me great flexibility without breaking existing code. I pack a dictionary before passing and unpack when retrieving. Perhaps you want to create a class instead? If you find yourself passing more than a handful of arguments to a function, and especially more than a handful of values returned from a function, then a class with methods might be a better way to combine state and behavior. Also, keep in mind that you can return a tuple from a function if you want to return two or three values and assign them to names: x, y, z = compute_xyz() You mention unpacking your dictionary after the function call. How do you do that? Isn't that a cumbersome and repetitive operation? I will give the locals approach a try, it seems a little more clumsy than simply passing the variables to the function. Thanks again for your input. ---Andrew BTW, it's a little easier to follow the threads of conversation if you put your responses after the text you are responding to. This is known as bottom-posting, and is preferred to top-posting as you did here. -- Ned Batchelder, http://nedbatchelder.com -- https://mail.python.org/mailman/listinfo/python-list
Re: Help with changes in traceback stack from Python 2.7 to Python 3.x
On Apr 28, 2014, at 12:36 PM, Ned Batchelder wrote: On 4/27/14 5:51 PM, Andrew Konstantaras wrote: > I guess I am missing something big as I am looking for a shorthand way > of doing the following: > > dctA = dict(x=x, y=y, ... n=n) > Yes, your makeDict(x, y) is a shorthand for dict(x=x, y=y), but there are many things you can do with dict that you can't do with makeDict. What is the makeDict equivalent of: dict(x=12, y=self.y, z=a+b) The code you have allows you more compact expression, but it brings fragility and surprise. > This is, as I understand it a very natural way of using a dictionary. > It seems that this syntax is unnecessarily redundant and hence my goal > of writing something more compact. Perhaps the way I am doing it is a > little unorthodox, but the ultimate use of a dictionary is, as I > understand it, completely in line with how dictionaries were designed to > be used. In my other code, I often use these dictionaries to pass > arguments to functions and return results. It allows me great > flexibility without breaking existing code. I pack a dictionary before > passing and unpack when retrieving. Perhaps you want to create a class instead? If you find yourself passing more than a handful of arguments to a function, and especially more than a handful of values returned from a function, then a class with methods might be a better way to combine state and behavior. Also, keep in mind that you can return a tuple from a function if you want to return two or three values and assign them to names: x, y, z = compute_xyz() You mention unpacking your dictionary after the function call. How do you do that? Isn't that a cumbersome and repetitive operation? One of the reasons I like using the dictionary over the tuple is that if I have a function that grows in functionality (i.e., I decide to return more data for new scenarios), I can just add the new object to the dictionary and I don't have to worry about changing the code every where else that used to call the function. Actually, that is one of the nice features of using a dictionary, I can check if the key is there and if it is pull it out. As I was dusting off this old code, I considered trying to implement this functionality through by creating a class. I never liked going through the stack, it seemed hacky, but I came to love using dictionaries as they have some great built in features. Again, thanks for the advice and I will focus on the class implementation. > > I will give the locals approach a try, it seems a little more clumsy > than simply passing the variables to the function. > > Thanks again for your input. > > ---Andrew BTW, it's a little easier to follow the threads of conversation if you put your responses after the text you are responding to. This is known as bottom-posting, and is preferred to top-posting as you did here. -- Ned Batchelder, http://nedbatchelder.com -- https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
Re: Sorting list alphabetically
On 4/28/2014 2:33 AM, Kev Dwyer wrote: Hello Terry, Regarding your second point, my mistake in not checking the link: I'd seen a similar one elsewhere and assumed they were the same. This link should work: http://msdn.microsoft.com/en-us/library/hzz3tw78 As to your first point, you're right, it seems setlocale(locale.LC_ALL, 'en_US.UTF-8') doesn't work on Windows. From what I read of the link above and http://msdn.microsoft.com/en-US/goglobal/bb896001.aspx given therein, I am going to guess that .UTF-8 is not supported for any language. It seems the locale name needs to be one of the aliases provided at http://msdn.microsoft.com/en-us/library/39cwe7zf, so for example locale.setlocale(locale.LC_ALL, 'usa') returns 'English_United States.1252'. Do you know if this is something people programming on Windows should just be aware of, or is there a case for a hint of some kind in the locale module documentation? *Definitely the latter. Perhaps you could open an issue with a specific suggestion. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: Soap list and soap users on this list
Hi Joseph, Sorry for the late response, I seem to have missed this post. On 04/17/14 21:34, Joseph L. Casale wrote: > I've been looking at Spyne to produce a service that > can accept a request formatted as follows: > > > http://..."; xmlns:xsi=http:/..." > xmlns:xsd="http://...";> > > > > > > > > https://gist.github.com/plq/11384113 Unfortunately, you need the latest Spyne from https://github.com/arskom/spyne, this doesn't work with 2.10 2.11 is due around end of may, beginning of june. Ping back if you got any other questions. Best, Burak -- https://mail.python.org/mailman/listinfo/python-list
RE: Soap list and soap users on this list
> https://gist.github.com/plq/11384113 > > Unfortunately, you need the latest Spyne from > https://github.com/arskom/spyne, this doesn't work with 2.10 > > 2.11 is due around end of may, beginning of june. > > Ping back if you got any other questions. Burak, Thanks a ton! I've just pulled this down and started working through it. Much appreciated! jlc -- https://mail.python.org/mailman/listinfo/python-list
Re: Help with changes in traceback stack from Python 2.7 to Python 3.x
On Tue, Apr 29, 2014 at 5:50 AM, Andrew Konstantaras wrote:
> Actually, that is one of the nice features of using a dictionary, I can
> check if the key is there and if it is pull it out. As I was dusting off
> this old code, I considered trying to implement this functionality through
> by creating a class. I never liked going through the stack, it seemed
> hacky, but I came to love using dictionaries as they have some great built
> in features.
In that case, consider using function named arguments. You can simply
list a whole lot of args with defaults, and then provide values for
the exact ones you want:
def f(a=1, b=2, c=3, d=4, e=5):
print("My args are",a,b,c,d,e)
f() # all defaults, like an empty dict
f(d=123) # all defaults but one
f(10,20,e=7) # specify the early ones positionally if you always pass those
This is a really REALLY handy feature.
ChrisA
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Re: MacOS 10.9.2: threading error using python.org 2.7.6 distribution
On Sunday, 27 April 2014 10:33:38 UTC-4, Chris Angelico wrote: > In most contexts, "thread unsafe" simply means that you can't use the > same facilities simultaneously from two threads (eg a lot of database > connection libraries are thread unsafe with regard to a single > connection, as they'll simply write to a pipe or socket and then read > a response from it). But processes and threads are, on many systems, > linked. Just the act of spinning off a new thread and then forking can > potentially cause problems. Those are the exact sorts of issues that > you'll see when you switch OSes, as it's the underlying thread/process > model that's significant. (Particularly of note is that Windows is > *very* different from Unix-based systems, in that subprocess > management is not done by forking. But not applicable here.) > Thanks, I'll keep all that in mind. I have to wonder how much of a problem it is here though, since I was able to demonstrate a functioning fork inside a new thread further up in the discussion. I have a new development that I find interesting, and I'm wondering if you still think it's the same problem. I have taken that threading object and turned it into a normal function definition. It's still forking the external tool, but it's doing so in the main thread, and it is finished execution before any other threads are created. And I'm still getting the same error. Turns out it's not coming from the threading module, but from the subprocess module instead. Specifically, like 709 of /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py which is this: try: self._execute_child(args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, to_close, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) except Exception: I get the "Warning: No stack to get attribute from" twice when that self._execute_child() call is made. I've tried stepping into it to narrow it down further, but I'm getting weird behaviour from the debugger that I've never seen before once I do that. It's making it hard to track down exactly where the error is occurring. Interestingly, it's not actually raising an exception there. The except block is not being run. -- https://mail.python.org/mailman/listinfo/python-list
Re: MacOS 10.9.2: threading error using python.org 2.7.6 distribution
On Tue, Apr 29, 2014 at 8:50 AM, Matthew Pounsett wrote: > Thanks, I'll keep all that in mind. I have to wonder how much of a problem > it is here though, since I was able to demonstrate a functioning fork inside > a new thread further up in the discussion. > Yeah, it's really hard to pin down sometimes. I once discovered a problem whereby I was unable to spin off subprocesses that did certain things, but I could do a trivial subprocess (I think I fork/exec'd to the echo command or something) and that worked fine. Turned out to be a bug in one of my signal handlers, but the error was being reported at the point of the forking. > I have a new development that I find interesting, and I'm wondering if you > still think it's the same problem. > > I have taken that threading object and turned it into a normal function > definition. It's still forking the external tool, but it's doing so in the > main thread, and it is finished execution before any other threads are > created. And I'm still getting the same error. > Interesting. That ought to eliminate all possibility of thread-vs-process issues. Can you post the smallest piece of code that exhibits the same failure? ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Inconsistent viewkeys behaviour
Terry Reedy wrote: The left operand determines the result. The manual specifies that < and > do not have to be consistent. But I suspect that when 3.x dict.keys() was backported to 2.7.0, no one thought to update set, whereas the backported key view code already had the comparison. The question is why set() is raising an exception instead of returning NotImplemented to give the other operand a chance. -- Greg -- https://mail.python.org/mailman/listinfo/python-list
Re: Significant digits in a float?
On Mon, 28 Apr 2014 12:00:23 -0400, Roy Smith wrote:
[...]
> Fundamentally, these numbers have between 0 and 4 decimal digits of
> precision,
I'm surprised that you have a source of data with variable precision,
especially one that varies by a factor of TEN THOUSAND. The difference
between 0 and 4 decimal digits is equivalent to measuring some lengths to
the nearest metre, some to the nearest centimetre, and some to the
nearest 0.1 of a millimetre. That's very unusual and I don't know what
justification you have for combining such a mix of data sources.
One possible interpretation of your post is that you have a source of
floats, where all the numbers are actually measured to the same
precision, and you've simply misinterpreted the fact that some of them
look like they have less precision. Since you indicate that 4 decimal
digits is the maximum, I'm going with 4 decimal digits. So if your data
includes the float 23.5, that's 23.5 measured to a precision of four
decimal places (that is, it's 23.5000, not 23.5001 or 23.4999).
On the other hand, if you're getting your values as *strings*, that's
another story. If you can trust the strings, they'll tell you how many
decimal places: "23.5" is only one decimal place, "23.5000" is four.
But then what to make of your later example?
> 40.752801 ==> 4
Python floats (C doubles) are quite capable of distinguishing between
40.7528 and 40.752801. They are distinct numbers:
py> 40.752801 - 40.7528
7.105427357601002e-15
so if a number is recorded as 40.752801 presumably it is because
it was measured as 40.752801. (How that precision can be
justified, I don't know! Does it come from the Large Hadron Collider?) If
it were intended to be 40.7528, I expect it would have be recorded as
40.7528. What reason do you have to think that something recorded to 14
decimal places was only intended to have been recorded to 4?
Without knowing more about how your data is generated, I can't advise you
much, but the whole scenario as you have described it makes me think that
*somebody* is doing something wrong. Perhaps you need to explain why
you're doing this, as it seems numerically broken.
> Is there any clean way to do that? The best I've come up with so far is
> to str() them and parse the remaining string to see how many digits it
> put after the decimal point.
I really think you need to go back to the source. Trying to infer the
precision of the measurements from the accident of the string formatting
seems pretty dubious to me.
But I suppose if you wanted to infer the number of digits after the
decimal place, excluding trailing zeroes (why, I do not understand), up
to a maximum of four digits, then you could do:
s = "%.4f" % number # rounds to four decimal places
s = s.rstrip("0") # ignore trailing zeroes, whether significant or not
count = len(s.split(".")[1])
Assuming all the numbers fit in the range where they are shown in non-
exponential format. If you have to handle numbers like 1.23e19 as well,
you'll have to parse the string more carefully. (Keep in mind that most
floats above a certain size are all integer-valued.)
> The numbers are given to me as Python floats; I have no control over
> that.
If that's the case, what makes you think that two floats from the same
data set were measured to different precision? Given that you don't see
strings, only floats, I would say that your problem is unsolvable.
Whether I measure something to one decimal place and get 23.5, or four
decimal places and get 23.5000, the float you see will be the same.
Perhaps you ought to be using Decimal rather than float. Floats have a
fixed precision, while Decimals can be configured. Then the right way to
answer your question is to inspect the number:
py> from decimal import Decimal as D
py> x = D("23.5000")
py> x.as_tuple()
DecimalTuple(sign=0, digits=(2, 3, 5, 0, 0, 0), exponent=-4)
The number of decimal digits precision is -exponent.
> I'm willing to accept that fact that I won't be able to differentiate
> between float("38.0") and float("38."). Both of those map to 1,
> which is OK for my purposes.
That seems... well, "bizarre and wrong" are the only words that come to
mind. If I were recording data as "38." and you told me I had
measured it to only one decimal place accuracy, I wouldn't be too
pleased. Maybe if I understood the context better?
How about 38.12 and 38.1200?
By the way, you contradict yourself here. Earlier, you described 38.0 as
having zero decimal places (which is wrong). Here you describe it as
having one, which is correct, and then in a later post you describe it as
having zero decimal places again.
--
Steven D'Aprano
http://import-that.dreamwidth.org/
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Re: Significant digits in a float?
Steven D'Aprano writes: > By the way, you contradict yourself here. Earlier, you described 38.0 as > having zero decimal places (which is wrong). Here you describe it as > having one, which is correct, and then in a later post you describe it as > having zero decimal places again. I get the impression that this is at the core of the misunderstanding. Having a number's representation ending in “….0” does not mean zero decimal places; it has exactly one. The value's representation contains the digit “0” after the decimal point, but that digit is significant to the precision of the representation. If the problem could be stated such that “38.0” and “38” and “38.000” are consistently described with the correct number of decimal digits of precision (in those examples: one, zero, and three), maybe the discussion would make more sense. -- \ “Men never do evil so completely and cheerfully as when they do | `\it from religious conviction.” —Blaise Pascal (1623–1662), | _o__) Pensées, #894. | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
Re: Significant digits in a float?
On Tue, 29 Apr 2014 13:23:07 +1000, Ben Finney wrote:
> Steven D'Aprano writes:
>
>> By the way, you contradict yourself here. Earlier, you described 38.0
>> as having zero decimal places (which is wrong). Here you describe it as
>> having one, which is correct, and then in a later post you describe it
>> as having zero decimal places again.
>
> I get the impression that this is at the core of the misunderstanding.
> Having a number's representation ending in “….0” does not mean zero
> decimal places; it has exactly one. The value's representation contains
> the digit “0” after the decimal point, but that digit is significant to
> the precision of the representation.
>
> If the problem could be stated such that “38.0” and “38” and “38.000”
> are consistently described with the correct number of decimal digits of
> precision (in those examples: one, zero, and three), maybe the
> discussion would make more sense.
It's actually trickier than that. Digits of precision can refer to
measurement error, or to the underlying storage type. Python floats are C
doubles, so they have 64 bits of precision (approximately 17 decimal
digits, if I remember correctly) regardless of the precision of the
measurement. The OP (Roy) is, I think, trying to guess the measurement
precision after the fact, given a float. If the measurement error really
does differ from value to value, I don't think he'll have much luck:
given a float like 23.0, all we can say is that it has *at least* zero
significant decimal places. 23.1 has at least one, 23. has at least
four.
If you can put an upper bound on the precision, as Roy indicates he can,
then perhaps a reasonable approach is to convert to a string rounded to
four decimal places, then strip trailing zeroes:
py> x = 1234.1 # actual internal is closer to 1234.009
py> ("%.4f" % x).rstrip('0')
'1234.1'
then count the number of digits after the dot. (This assumes that the
string formatting routines are correctly rounded, which they should be on
*most* platforms.) But again, this only gives a lower bound to the number
of significant digits -- it's at least one, but might be more.
--
Steven
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Re: Sorting list alphabetically
Terry Reedy wrote: > On 4/28/2014 2:33 AM, Kev Dwyer wrote: > >> Hello Terry, >> >> Regarding your second point, my mistake in not checking the link: >> I'd seen a similar one elsewhere and assumed they were the same. >> >> This link should work: >> http://msdn.microsoft.com/en-us/library/hzz3tw78 >> >> >> As to your first point, you're right, it seems setlocale(locale.LC_ALL, >> 'en_US.UTF-8') doesn't work on Windows. > > From what I read of the link above and > http://msdn.microsoft.com/en-US/goglobal/bb896001.aspx > given therein, I am going to guess that .UTF-8 is not supported for any > language. > >> It seems the locale name needs to be one of the aliases provided >> at http://msdn.microsoft.com/en-us/library/39cwe7zf, so for example >> locale.setlocale(locale.LC_ALL, 'usa') returns >> 'English_United States.1252'. >> >> Do you know if this is something people programming on Windows >> should just be aware of, or is there a case for a hint of some >> kind in the locale module documentation? > > *Definitely the latter. Perhaps you could open an issue with a specific > suggestion. > Thanks! I'll try to write something up this weekend. -- https://mail.python.org/mailman/listinfo/python-list
