Re: Python Windows Extensions for Mac
In article , Chris Rebert wrote: >On Fri, Aug 19, 2011 at 1:02 PM, johnny.venter wrote: >> >> Hello, I am looking for the Python Windows Extensions to see if they can be >> installed on a Mac.THanks. > >Your request is nonsensical. That's not completely true. >pywin32 wraps the Windows API libraries. >Mac OS X is not Windows; it does not implement the Windows API. Thus, >there is nothing for pywin32 to wrap on a Mac. Again: Not completely true. One could run python under wine and get -- at least a part of -- the Windows API. >Square peg, round hole. wine might be the tool that makes the square peg round. Best regards, Günther -- http://mail.python.org/mailman/listinfo/python-list
Re: Stop quoting spam [was Re: Hot Girls ...]
On Sat, Aug 20, 2011 at 9:24 AM, Albert W. Hopkins wrote: > > > On Friday, August 19 at 17:12 (-0400), Matty Sarro said: > >> >> If you're that offended then spend the cycles fixing the damn list so >> it >> stops having so much spam. You realize spam comes in almost >> constantly, >> right? Enough that multiple tines over the past weeks there have been >> no >> less than 3 threads about it. > > For me, the original post ended in my spam box, which means my filter is > doing it's job, but when you re-post it, my filter did not regard it as > spam. I actually wish it had. Therefore you are an enabler. > > >> If php, red hat, and perl can manage it for their lists, why not >> python? Is >> that a statement about python programmers? >> > > The python list is (also) a Usenet newsgroup. Usenet is distributed and > therefore there is no central place to filter spam (each usenet host > would have to have its own filter and what one considers spam another > might consider ham)... anyway, that's neither here nor there. Having my > own filter usually works. > > I'm not here to dis you, just to try to help you understand the how/why > regarding the re-post and why your attitude about it might give the > impression of apathy toward your peer community. > > > > > -- > http://mail.python.org/mailman/listinfo/python-list > I found said joke rather funny :P -- http://mail.python.org/mailman/listinfo/python-list
Compare tuples of different lenght
Hi, I have a list of tuples: [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] I would like to compare all the tuples to each other and if one element if found two tuples the smallest tuples is removed from the list. example if tuple 1 and tuple 3 are compare it should find that a single element in each are the same and tuple 1 should be removed resulting in [(12,13),(2,3,4),(8,),(5,6),(7,8,9),] the same for tuple 4 and 6 resulting in [(12,13),(2,3,4),(5,6),(7,8,9),] is this possible as I am having no success. Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Help on PyQt4 QProcess
On Fri, 19 Aug 2011 14:32:12 -0700 (PDT), Edgar Fuentes
wrote:
> On Aug 19, 4:21 pm, Carl Banks wrote:
>> On Friday, August 19, 2011 12:55:40 PM UTC-7, Edgar Fuentes wrote:
>> > On Aug 19, 1:56 pm, Phil Thompson
>> > wrote:
>> > > On Fri, 19 Aug 2011 10:15:20 -0700 (PDT), Edgar Fuentes
>> > > wrote:
>> > > > Dear friends,
>>
>> > > > I need execute an external program from a gui using PyQt4, to
avoid
>> > > > that hang the main thread, i must connect the signal
>> > > > "finished(int)"
>> > > > of a QProcess to work properly.
>>
>> > > > for example, why this program don't work?
>>
>> > > > from PyQt4.QtCore import QProcess
>> > > > pro = QProcess() # create QProcess object
>> > > > pro.connect(pro, SIGNAL('started()'), lambda
>> > > > x="started":print(x)) # connect
>> > > > pro.connect(pro, SIGNAL("finished(int)"), lambda
>> > > > x="finished":print(x))
>> > > > pro.start('python',['hello.py']) # star hello.py
program
>> > > > (contain print("hello world!"))
>> > > > timeout = -1
>> > > > pro.waitForFinished(timeout)
>> > > > print(pro.readAllStandardOutput().data())
>>
>> > > > output:
>>
>> > > > started
>> > > > 0
>> > > > b'hello world!\n'
>>
>> > > > see that not emit the signal finished(int)
>>
>> > > Yes it is, and your lambda slot is printing "0" which is the return
>> > > code
>> > > of the process.
>>
>> > > Phil
>>
>> > Ok, but the output should be:
>>
>> > started
>> > b'hello world!\n'
>> > finished
>>
>> > no?.
>>
>> > thanks Phil
>>
>> Two issues. First of all, your slot for the finished function does not
>> have the correct prototype, and it's accidentally not throwing an
>> exception because of your unnecessary use of default arguments.
Anyway,
>> to fix that, try this:
>>
>> pro.connect(pro, SIGNAL("finished(int)"), lambda v,
>> x="finished":print(x))
>>
>> Notice that it adds an argument to the lambda (v) that accepts the int
>> argument of the signal. If you don't have that argument there, the int
>> argument goes into x, which is why Python prints 0 instead of
"finished".
>>
>> Second, processess run asynchrously, and because of line-buffering, IO
>> can output asynchronously, and so there's no guarantee what order
output
>> occurs. You might try calling the python subprocess with the '-u'
switch
>> to force unbuffered IO, which might be enough to force synchronous
output
>> (depending on how signal/slot and subprocess semantics are
implemented).
>>
>> Carl Banks
>
> Thanks Carl, your intervention was very helpful for me, this solve my
> semantic error. I need to study more about signal/slots and process.
In which case you should look at the modern, Pythonic connection syntax
rather than the old one...
pro.started.connect(lambda: print("started"))
pro.finished.connect(lambda: print("finished"))
Phil
--
http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
On Sat, Aug 20, 2011 at 1:25 AM, Jurgens de Bruin wrote: > Hi, > > I have a list of tuples: > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > I would like to compare all the tuples to each other and if one > element if found two tuples the smallest tuples is removed from the > list. So, would [(5,6), (6,7,8)] become [(6,7,8)] ? If no, then I believe you're trying to solve the set covering problem: http://en.wikipedia.org/wiki/Set_cover_problem Cheers, Chris -- http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
On Aug 20, 10:45 am, Chris Rebert wrote: > On Sat, Aug 20, 2011 at 1:25 AM, Jurgens de Bruin wrote: > > > Hi, > > > I have a list of tuples: > > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > > I would like to compare all the tuples to each other and if one > > element if found two tuples the smallest tuples is removed from the > > list. > > So, would [(5,6), (6,7,8)] become [(6,7,8)] ? > > If no, then I believe you're trying to solve the set covering > problem:http://en.wikipedia.org/wiki/Set_cover_problem > > Cheers, > Chris > --http://rebertia.com [(5,6), (6,7,8)] would become [(6,7,8)]. Thanks for the response -- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
On Aug 20, 10:45 am, Chris Rebert wrote: > On Sat, Aug 20, 2011 at 1:25 AM, Jurgens de Bruin wrote: > > > Hi, > > > I have a list of tuples: > > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > > I would like to compare all the tuples to each other and if one > > element if found two tuples the smallest tuples is removed from the > > list. > > So, would [(5,6), (6,7,8)] become [(6,7,8)] ? > > If no, then I believe you're trying to solve the set covering > problem:http://en.wikipedia.org/wiki/Set_cover_problem > > Cheers, > Chris > --http://rebertia.com [(5,6), (6,7,8)] will indeed become [(6,7,8)] Tanks!! -- http://mail.python.org/mailman/listinfo/python-list
Python import search path
Hi, This is the directory tree. project └── sme ├── src │ ├── a.pth │ ├── sss.py └── test └── ttt.py I need to import sss.py in ttt.py. Found a few solution in python docs. A. sys.path.append B. add ***.pth file C. edit .../site-packages/site.py I found out that a.pth only works when in directory like /usr/lib/pythonX.Y/site-packages instead of in current directory. I think A is not so pretty, and I don't have root privilege to use B and C. So any both more elegant and practical solutions? Thanks. Kevin Zhang -- http://mail.python.org/mailman/listinfo/python-list
Re: Stop quoting spam [was Re: Hot Girls ...]
On Fri, 19 Aug 2011 17:10:49 -0400 Rodrick Brown wrote: > It's not the end of the world calm down I thought it was quite funny for a > friday joke! The first message might have been funny (if you are twelve) but the rest were annoying and insulting. -- D'Arcy J.M. Cain | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
hello python
from china -- designed by wk...@qq.com-- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
Jurgens de Bruin wrote: > Hi, > > I have a list of tuples: > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > I would like to compare all the tuples to each other and if one > element if found two tuples the smallest tuples is removed from the > list. It's not clear what you mean by "smallest" tuple. Is (8,) smaller than (7,8,9)? I'm going to guess you care only about the length of the tuple, and not the items themselves. Let's start with a couple of helper functions. def compare(t1, t2): 'Return -1 if t1 is "smaller" than t2, 0 if equal, and +1 if "bigger".' if len(t1) < len(t2): return -1 elif len(t1) > len(t2): return 1 else: return 0 def match_any_item(t1, t2): try: s1 = set(t1) s2 = set(t2) return bool(s1 & s2) except TypeError: # Can't convert to sets because at least one item is mutable. # Let's do this the slow(?) way. matched = [x for x in t1 if x in t2] return bool(matched) list_of_tuples = [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] flags = [True]*len(list_of_tuples) for i,t1 in enumerate(list_of_tuples): for j in range(i+1, len(list_of_tuples)): t2 = list_of_tuples[j] if match_any_item(t1, t2): n = compare(t1, t2) if n == -1: # Flag t1 to be removed. flags[i] = False elif n == 1: # Flag t2 to be removed. flags[j] = False saved_tuples = [] for t,flag in zip(list_of_tuples, flags): if flag: saved_tuples.append(t) This gives: >>> saved_tuples [(12, 13), (2, 3, 4), (5, 6), (7, 8, 9)] which matches what you wanted: > [(12,13),(2,3,4),(5,6),(7,8,9),] -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
On Aug 20, 12:17 pm, Steven D'Aprano wrote: > Jurgens de Bruin wrote: > > Hi, > > > I have a list of tuples: > > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > > I would like to compare all the tuples to each other and if one > > element if found two tuples the smallest tuples is removed from the > > list. > > It's not clear what you mean by "smallest" tuple. Is (8,) smaller than > (7,8,9)? > > I'm going to guess you care only about the length of the tuple, and not the > items themselves. > > Let's start with a couple of helper functions. > > def compare(t1, t2): > 'Return -1 if t1 is "smaller" than t2, 0 if equal, and +1 if "bigger".' > if len(t1) < len(t2): return -1 > elif len(t1) > len(t2): return 1 > else: return 0 > > def match_any_item(t1, t2): > try: > s1 = set(t1) > s2 = set(t2) > return bool(s1 & s2) > except TypeError: > # Can't convert to sets because at least one item is mutable. > # Let's do this the slow(?) way. > matched = [x for x in t1 if x in t2] > return bool(matched) > > list_of_tuples = [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > flags = [True]*len(list_of_tuples) > for i,t1 in enumerate(list_of_tuples): > for j in range(i+1, len(list_of_tuples)): > t2 = list_of_tuples[j] > if match_any_item(t1, t2): > n = compare(t1, t2) > if n == -1: > # Flag t1 to be removed. > flags[i] = False > elif n == 1: > # Flag t2 to be removed. > flags[j] = False > > saved_tuples = [] > for t,flag in zip(list_of_tuples, flags): > if flag: saved_tuples.append(t) > > This gives: > > >>> saved_tuples > > [(12, 13), (2, 3, 4), (5, 6), (7, 8, 9)] > > which matches what you wanted: > > > [(12,13),(2,3,4),(5,6),(7,8,9),] > > -- > Steven Thanks Steven. This works great!!! Appreciated very much!!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
Jurgens de Bruin wrote: > Hi, > > I have a list of tuples: > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > I would like to compare all the tuples to each other and if one > element if found two tuples the smallest tuples is removed from the > list. > > example if tuple 1 and tuple 3 are compare it should find that a > single element in each are the same and tuple 1 should be removed > resulting in > > [(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > the same for tuple 4 and 6 resulting in > > [(12,13),(2,3,4),(5,6),(7,8,9),] > > is this possible as I am having no success. > > Thanks from collections import Counter, defaultdict from itertools import chain def process_counter(sample): c = Counter() d = defaultdict(list) for items in sample: c.update(items) d[len(items)].append(items) result = [] for cluster in sorted(d.values(), key=len): c.subtract(chain.from_iterable(cluster)) for items in cluster: if not any(c[item] for item in items): result.append(items) result.sort(key=sample.index) return result if __name__ == "__main__": for process in [process_counter]: print process.__name__ sample = [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] wanted = [(12,13),(2,3,4),(5,6),(7,8,9),] assert process(sample) == wanted sample = [(5,6), (6,7,8)] wanted = [(6,7,8)] got = process(sample) assert got == wanted sample = wanted = [(5, 6), (6, 7)] assert process(sample) == wanted sample = [(1,), (1, 2), (2, 3, 4)] wanted = [(2, 3, 4)] assert process(sample) == wanted -- http://mail.python.org/mailman/listinfo/python-list
Re: Hot Girls are Looking for Sex
Well, they might be indented in the right places but i don't know if loops, conditions, functions, if they all happen or not. :) Happy hacking. Krishnakant, On 20/08/11 01:47, Matty Sarro wrote: That's great - but do they program in python? On Fri, Aug 19, 2011 at 2:38 PM, Sajjad Ahmad wrote: See All details on http://hotelandtourism9.blogspot.com/2011/08/indian-hotels-wall-st-effect.html . See All details on http://hotelandtourism9.blogspot.com/2011/08/indian-hotels-wall-st-effect.html . See All details on http://hotelandtourism9.blogspot.com/2011/08/indian-hotels-wall-st-effect.html . See All details on http://hotelandtourism9.blogspot.com/2011/08/indian-hotels-wall-st-effect.html . See All details on http://hotelandtourism9.blogspot.com/2011/08/indian-hotels-wall-st-effect.html . -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Stop quoting spam [was Re: Hot Girls ...]
On Sat, Aug 20, 2011 at 4:16 AM, Alec Taylor wrote: >> ... > I found said joke rather funny :P Perhaps, as a retired amateur comedian, my standards are too high, but I don't think adding a smilie to a stupid post suddenly turns it into a joke. Nevertheless, the quality of the attempt is not really the issue here. The would-be humorist did not need to quote the spam. Please, don't do it. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python import search path
On Sat, Aug 20, 2011 at 10:52 AM, Kevin Zhang wrote: > Found a few solution in python docs. > A. sys.path.append > I think A is not so pretty, and I don't have root privilege to use B and C. > So any both more elegant and practical solutions? If, as I understand from your directory tree, ttt.py is a tester for sss.py, then I'd say this is the right option. It's only going to be used in the special environment of testing, so it's okay to have a single line of code up the top that makes it convenient. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Stop quoting spam [was Re: Hot Girls ...]
On Sat, 20 Aug 2011 08:17:32 -0400 David Robinow wrote: > > I found said joke rather funny :P > Perhaps, as a retired amateur comedian, my standards are too high, How does one retire from amateur status? Do you suddenly start charging for telling jokes? :-) > but I don't think adding a smilie to a stupid post suddenly turns it > into a joke. Nevertheless, the quality of the attempt is not really > the issue here. The would-be humorist did not need to quote the spam. Well, exactly. I don't think that anyone made any comment about the quality of the joke when talking about the first posting. The only thing that people said was that he shouldn't have repeated the spam. Everyone, including the original poster, who defended the post did so on the grounds that it was funny. That's certainly debatable but no one was telling him not to post until he gets funnier. http://en.wikipedia.org/wiki/Straw_man Whether the post was funny or not is a judgment call. No one is saying not to post unfunny jokes because no one is the arbiter of what's funny. If you want to argue with the complainers, argue with their actual complaint. Tell us why it is OK to repeat spam with all the spammy URLS intact By the way, my joke above is hilarious. -- D'Arcy J.M. Cain | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Really, stop repeating spam! (Was: Hot Girls...)
On Sat, 20 Aug 2011 15:16:08 +0530 hackingKK wrote: > Well, they might be indented in the right places but i don't know if > loops, conditions, functions, if they all happen or not. > :) [Entire spam deleted AGAIN] Good grief! Haven't you seen all the followups to that posting you replied to? Are you two actually in cahoots with the spammer? Wait, I get it. The spammer, Matty and you are all on gmail. You are all the same person, aren't you? -- D'Arcy J.M. Cain | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: Really, stop repeating spam! (Was: Hot Girls...)
On Sat, Aug 20, 2011 at 3:57 PM, D'Arcy J.M. Cain wrote: > Wait, I get it. The spammer, Matty and you are all on gmail. You are > all the same person, aren't you? > Gmail is all one person now? That would explain why I keep seeing things I agree with. I had no idea there were so many of me around! Wait, does that make me Agent Smith? ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Compare tuples of different lenght
On Sat, 20 Aug 2011 01:25:18 -0700 (PDT) Jurgens de Bruin wrote: > Hi, > > I have a list of tuples: > > [(2,),(12,13),(2,3,4),(8,),(5,6),(7,8,9),] > > I would like to compare all the tuples to each other and if one > element if found two tuples the smallest tuples is removed from the > list. [...] This should work: def long_match(tuples): sorted_tuples = sorted(tuples, key=len) for n, t in enumerate(sorted_tuples): for s in sorted_tuples[n + 1:]: if len(s) > len(t) and any(i in s for i in t): tuples.remove(t) break return tuples Regards, John -- http://mail.python.org/mailman/listinfo/python-list
Re: testing if a list contains a sublist
On Mon, Aug 15, 2011 at 4:26 PM, Johannes wrote: > hi list, > what is the best way to check if a given list (lets call it l1) is > totally contained in a second list (l2)? > > for example: > l1 = [1,2], l2 = [1,2,3,4,5] -> l1 is contained in l2 > l1 = [1,2,2,], l2 = [1,2,3,4,5] -> l1 is not contained in l2 > l1 = [1,2,3], l2 = [1,3,5,7] -> l1 is not contained in l2 > > my problem is the second example, which makes it impossible to work with > sets insteads of lists. But something like set.issubset for lists would > be nice. > > greatz Johannes > -- > http://mail.python.org/mailman/listinfo/python-list > Probably not the most efficient way, but I wanted to mention it: from difflib import SequenceMatcher def list_in(a, b): '''Is a completely contained in b?''' matcher = SequenceMatcher(a=a, b=b) m = matcher.find_longest_match(0, len(a), 0, len(b)) return m.size == len(a) Cheers, ~Simon -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Windows Extensions for Mac
On 8/19/11 4:02 PM, johnny.venter wrote: Hello, I am looking for the Python Windows Extensions to see if they can be installed on a Mac.THanks. You can certainly try to install them via easy_install, I supposed, but it's doubtful they would do anything, as the Mac does not support win32 API calls any more than Windows supports Cocoa/Objective-C calls. -- Kevin Walzer Code by Kevin http://www.codebykevin.com -- http://mail.python.org/mailman/listinfo/python-list
Re: List spam
I find python group is filled with spam mails, is there any way to filter these mails before sending it to the group. I can't see this situation with similar user group, such as the jsr. George. On 20/08/2011 07:07, "Ben Finney" wrote: > Javier writes: > You will lose a lot of people > asking/answering interesting stuff, and > maybe eventually the list will > die. I don't think it would die, but the chances are greater that it > would become insular and further disconnected from the Python community, > and hence far less useful. > Me (like many people with little free time) > seldom post in > blogs/forums/mailing lists where I need to register. +1 -- > \ ³Ignorance more frequently begets confidence than does | `\ > knowledge.² Charles Darwin, _The Descent of Man_, 1871 | _o__) > | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
extended slicing and negative stop value problem
Would it be a good idea to change Python definition so that a[10, -1, -1] referred to the elements starting with position 10, going down to the beginning? This would require disabling the "negative stop value means counting from the end of the array" magic whenever the step value is negative. The reason for this idea is that many people (me including) try to use extended slices with negative step values, only to realize that they are messed up. For example, if your stop value is reduced in a loop from a positive number to -1, the behavior breaks whenever it hits -1. -- http://mail.python.org/mailman/listinfo/python-list
Re: extended slicing and negative stop value problem
On Sat, Aug 20, 2011 at 7:20 PM, Max Moroz wrote: > Would it be a good idea to change Python definition so that a[10, -1, -1] > referred to the elements starting with position 10, going down to the > beginning? Well, first off I think it's a dangerous idea to change semantics of something like that. I can see your use case, but I think that what you want is covered by simply omitting the stop marker: >>> a="qwertyuiopasdfghjklzxcvbnm" >>> a[10:1:-1] 'apoiuytre' >>> a[10:0:-1] 'apoiuytrew' >>> a[10::-1] 'apoiuytrewq' If you're using a variable for the stop value, you just need to set it to an explicit None if it would fall negative: >>> a[10:None:-1] 'apoiuytrewq' Hope that helps! ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: try... except with unknown error types
Steven D'Aprano writes: >> You can catch all exceptions by catching the base class Exception: > > Except that is nearly always poor advice, because it catches too much: it > hides bugs in code, as well as things which should be caught. > You should always catch the absolute minimum you need to catch. But there's no way to know what that minimum is. Python libraries throw all sorts of exceptions that their documentation doesn't mention. Java's checked exceptions are obnoxious but they do have their attractions. -- http://mail.python.org/mailman/listinfo/python-list
Re: extended slicing and negative stop value problem
On Aug 20, 11:29 am, Chris Angelico wrote: > If you're using a variable for the stop value, you just need to set it > to an explicit None if it would fall negative: > > >>> a[10:None:-1] > That doesn't work if it's set in a loop or if it's calculated as a formula. For example, this very simple code doesn't work because of the "-1 problem". # find the longest substring that reads the same left to right and right to left for substr_length in range(len(input),0,-1): for starting_pos in range(len(input)-substr_length+1): ending_pos = starting_pos + substr_length - 1 if input[starting_pos:ending_pos+1] == input[ending_pos : starting_pos-1 : -1]: print(input[starting_pos:ending_pos+1]) exit(0) Of course you can rewrite it, but it becomes quite ugly. (Not to mention, people who learn the language would not always know this, and will end up with a bug.) -- http://mail.python.org/mailman/listinfo/python-list
Re: extended slicing and negative stop value problem
On Sat, Aug 20, 2011 at 7:52 PM, Max wrote: > That doesn't work if it's set in a loop or if it's calculated as a > formula. For example, this very simple code doesn't work because of > the "-1 problem". > Right, which is what I meant by setting it to an explicit None: if input[starting_pos:ending_pos+1] == input[ending_pos : starting_pos-1 if starting_pos >= 0 else None : -1]: You're right that it starts to get ugly, though. Of course, there are other ways to find the longest palindromic substring in a string: # I wouldn't bother counting a one-character "palindrome" for substr_length in range(len(input),1,-1): for starting_pos in range(len(input)-substr_length+1): ending_pos = starting_pos + substr_length - 1 testme = input[starting_pos:ending_pos+1] if testme == testme[::-1]: print(testme) exit(0) That is, snip out the string and then reverse that snipped piece, rather than reverse-slicing from the original. This doesn't solve the issue of slicing backwards with variable halts, though. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: try... except with unknown error types
Paul Rubin wrote: > Steven D'Aprano writes: >>> You can catch all exceptions by catching the base class Exception: >> >> Except that is nearly always poor advice, because it catches too much: it >> hides bugs in code, as well as things which should be caught. >> You should always catch the absolute minimum you need to catch. > > But there's no way to know what that minimum is. Python libraries throw > all sorts of exceptions that their documentation doesn't mention. Yes, you're absolutely correct. But it's also irrelevant. Most of those exceptions should not be caught, even if you know what they are, because they represent either bugs that should be fixed, or bad data which should raise an exception. A bare except, or except Exception, is hardly ever the right approach. As for exceptions which should be caught, they should be dealt with on a case-by-case basis. There's no need to identify all those obscure exception-raising cases ahead of time. After all, unless you're writing software for a nuclear reactor, or an aeroplane's autopilot, chances are that *bugs don't really matter*. That is to say, if you release software with a hidden bug, the consequences generally aren't very important. (Depends on the nature of the software, and the bug, of course. Sometimes bugs are important. How's your test suite?) At some point, you will get a bug report, and then you will fix the bug. The fix may involve catching an extra exception, or avoiding generating the exception in the first place. Trying to predict ahead of time every possible exception that could be raised, and deal with them correctly (as opposed to just sweeping them under the carpet), is not only impossible but also usually unnecessary. It took me a long time to realise that the world won't end if I write a piece of software with a bug. Now I realise that software is never finished, there's always going to be a next version, so trying to make it perfect is a fool's errand. It's very liberating :) > Java's checked exceptions are obnoxious but they do have their > attractions. No doubt about it, the concept is attractive, but a few Java heavyweights now consider checked exceptions to be a mistake. http://www.mindview.net/Etc/Discussions/CheckedExceptions http://radio-weblogs.com/0122027/stories/2003/04/01/JavasCheckedExceptionsWereAMistake.html More here: http://www.ibm.com/developerworks/java/library/j-jtp05254/index.html -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: try... except with unknown error types
On 8/19/2011 1:24 PM, John Gordon wrote: In<4e4ec405$0$29994$c3e8da3$54964...@news.astraweb.com> Steven D'Aprano writes: You can catch all exceptions by catching the base class Exception: Except that is nearly always poor advice, because it catches too much: it hides bugs in code, as well as things which should be caught. You should always catch the absolute minimum you need to catch. Right. When in doubt, catch EnvironmentError. That means something external to the program, at the OS or network level, has a problem. "Exception" covers errors which are program bugs, like references to undefined class members. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Re: extended slicing and negative stop value problem
Pardon me for breaking threading, but I don't have Max's original post. On Sat, Aug 20, 2011 at 7:20 PM, Max Moroz wrote: > Would it be a good idea to change Python definition so that a[10, -1, -1] I presume you mean slice notation a[10:-1:-1]. > referred to the elements starting with position 10, going down to the > beginning? No, almost certainly not. Such a change would break backwards compatibility, and so would only be allowed under very unusual circumstances: the current behaviour would have to be a major problem, or the new behaviour a huge benefit, or both, to make up for: (1) the extra work needed to change the behaviour (probably involving a "from __future__ import ..." feature for the first version or two); (2) breaking people's existing code; and (3) forcing people to learn the new behaviour and unlearn the old. Even if the old behaviour is "wrong", the work needed to fix it may be more than the benefit. If this was going to be "fixed", the time was probably about three years ago, when Python3 was just starting. Now such a change will probably need to wait for the hypothetical Python 4000. > This would require disabling the "negative stop value means counting from > the end of the array" magic whenever the step value is negative. Which will hurt people who expect the current behaviour: >>> a[8:-8:-1] [8, 7, 6, 5, 4, 3] > The reason for this idea is that many people (me including) try to use > extended slices with negative step values, only to realize that they are > messed up. For example, if your stop value is reduced in a loop from a > positive number to -1, the behavior breaks whenever it hits -1. Yes, negative step values are unintuitive, especially if the step is not -1. The solution is, "Don't do that then!". The usual advice is to do your slicing twice, reversing it the second time: a[0:11][::-1] # Instead of a[10:-1:-1], which looks like it should work, but doesn't. (or use the reversed() built-in instead of the second slice), or to write a helper function to adjust the indexes and get whatever behaviour you like. Hint: >>> a[10:-11:-1] [9, 8, 7, 6, 5, 4, 3, 2, 1, 0] -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Windows Extensions for Mac
Thank you all for the replies. I would like to query various Windows' objects and resources from Mac and/or Linux such as Active Directory users, network shares, group members, etc... What module or methods can I use with python to accomplish this? I found dcerpc might be the way to go. On Aug 20, 2011, at 1:39 PM, Kevin Walzer wrote: > On 8/19/11 4:02 PM, johnny.venter wrote: >> >> Hello, I am looking for the Python Windows Extensions to see if they can be >> installed on a Mac.THanks. >> > > You can certainly try to install them via easy_install, I supposed, but it's > doubtful they would do anything, as the Mac does not support win32 API calls > any more than Windows supports Cocoa/Objective-C calls. > > -- > Kevin Walzer > Code by Kevin > http://www.codebykevin.com > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Windows Extensions for Mac
On Sun, Aug 21, 2011 at 12:51 AM, Johnny Venter wrote: > Thank you all for the replies. I would like to query various Windows' objects > and resources from Mac and/or Linux such as Active Directory users, network > shares, group members, etc... What module or methods can I use with python to > accomplish this? > The concept doesn't have meaning on a non-Windows computer, so I am going to take the liberty of assuming that you really want to query them from a different computer - some kind of network query. If that's not the case, can you clarify exactly what your setup is? Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Replacement for the shelve module?
Robert Kern wrote: That's just incorrect. You shouldn't use (binary) floats for many *accounting* purposes, but for many financial/econometric analyses, floats are de rigeur and work much better than decimals There's a certain accounting package I work with that *does* use floats -- binary ones -- for accounting purposes, and somehow manages to get away with it. Not something I would recommend trying at home, though. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Replacement for the shelve module?
On Sun, Aug 21, 2011 at 1:37 AM, Gregory Ewing wrote: > There's a certain accounting package I work with that *does* > use floats -- binary ones -- for accounting purposes, and > somehow manages to get away with it. Not something I would > recommend trying at home, though. > Probably quite a few, actually. It's not a very visible problem so long as you always have plenty of "spare precision", and you round everything off to two decimals (or however many for your currency). Eventually you'll start seeing weird results that are a cent off, but you won't notice them often. And hey. You store $1.23 as 1.23, and it just works! It must be the right thing to do! Me, I store dollars-and-cents currency in cents. Always. But that's because I never need fractional cents. I'm not sure what the best way to handle fractional cents is, but I'm fairly confident that this isn't it: http://thedailywtf.com/Articles/Price-in-Nonsense.aspx ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Windows Extensions for Mac
Yes, I want to make my queries from a remote non-Windows computer. Here is the scenario: >From my mac, I want to use python to access and read objects from a remote >Windows computer joined to a Windows 2003 functional level domain. Given this, >what is the best way to accomplish this? On Aug 20, 2011, at 7:57 PM, Chris Angelico wrote: > On Sun, Aug 21, 2011 at 12:51 AM, Johnny Venter > wrote: >> Thank you all for the replies. I would like to query various Windows' >> objects and resources from Mac and/or Linux such as Active Directory users, >> network shares, group members, etc... What module or methods can I use with >> python to accomplish this? >> > > The concept doesn't have meaning on a non-Windows computer, so I am > going to take the liberty of assuming that you really want to query > them from a different computer - some kind of network query. If that's > not the case, can you clarify exactly what your setup is? > > Chris Angelico > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
