🌐 Mailman 3 January 2009 - Python-list - python.org

Re: why cannot assign to function call
by Erik Max Francis Jan. 2, 2009

Jan. 2, 2009

Derek Martin wrote: > On Fri, Jan 02, 2009 at 12:50:44PM -0800, Erik Max Francis wrote: >>>> Identity isn't defined on math objects, only on Python objects; there >>>> is no notion of 'is' in math. >>> This is also false, it even has its own operator (which requires >>> Unicode to display): ≡ >> That can mean a number of things, one of which means "is identically >> equal to," > > Quite so. > >> but identity means something different in mathematics than it means >> here. > > But for non-mutable objects, aren't they essentially the same? > Mathematics has no concept of "objects" in the sense that computer > science does, so of course the best you can really do is draw > parallels. That's exactly the point. There is no concept of object identity in mathematics, so the above statement that you called false is, in fact, true. The concept does not translate. >> In computer science, identity means that two expressions are >> represented by the same object, something which not only has no >> meaning in mathematics, > > We're getting way off track here, but I would argue this is also > false. Take sets, for example: > > A = { 1, 2, 3 } > B = { 1, 2, 3 } > > Is it not true that A ≡ B and in fact these two sets are the same, > i.e. they are not actually two different sets at all; the have the > same identity, even considering a definition of "identity" which > reflects that in Python? Only if you try to make up a concept of identity that mathematics doesn't already have. The existing concept, which you invoked, has nothing to do with _object_ identity, it just has to do with a broader equality. > I don't imagine I would agree, based on what I just said. To elaborate, > each side of the expression contain symbols which always evaluate to > the same constant. The identity of a constant is constant. :) Except identities don't have to contain constants at all. They can contain arbitrary expressions on either side of the "is identically equal to" symbol. Which clearly indicates that the symbol can't mean the same thing as the identity operator in computer science, as you were claiming it did. -- Erik Max Francis && max(a)alcyone.com && http://www.alcyone.com/max/ San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis There's something immoral about abandoning your own judgement. -- John F. Kennedy

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Re: why cannot assign to function call
by Erik Max Francis Jan. 2, 2009

Jan. 2, 2009

Derek Martin wrote: > On a mostly not related note: > > On Tue, Dec 30, 2008 at 07:52:26AM -0800, Aaron Brady wrote: >> According to some rules, these are ungrammatical sentences, due to >> plurality disagreement. Ex: >> >> The Morning Star is ... >> The Evening Star is ... >> *The Morning Star and The Evening Star is... >> *The Morning Star and The Evening Star are... >> >> Neither of the latter two is correct. (* marks ungrammatical.) As >> such, the listener isn't sure what meaning to take. > > This statement is false. The latter of the two is grammatically > correct. The subject is a compound subject joined by the conjunction > "and" which indicates that there are two subjects, and thus the plural > form of the verb is necessary and correct. > >> Identity isn't defined on math objects, only on Python objects; there >> is no notion of 'is' in math. > > This is also false, it even has its own operator (which requires > Unicode to display): ≡ That can mean a number of things, one of which means "is identically equal to," but identity means something different in mathematics than it means here. In mathematics, identity means a relationship that is true regardless of the value of the variables involved (as opposed to equality which is only true under more specific circumstances). In computer science, identity means that two expressions are represented by the same object, something which not only has no meaning in mathematics, but which should also be clear since mathematical identities need not have any individual variables on either side of the triple bar; take, for instance, the trigonometric identity cos^2 theta + sin^2 theta = 1. Even if you write this equation with the triple bar to represent a mathematical identity (which it is), it obviously doesn't say anything about which "objects" are the same as each other. -- Erik Max Francis && max(a)alcyone.com && http://www.alcyone.com/max/ San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis Scars are like memories. We do not have them removed. -- Chmeee

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Request For (gozerbot) Testers
by Bart Thate Jan. 2, 2009

Jan. 2, 2009

So 0.9 is getting in shape and there is one issue that keeps me from releasing 0.9 and that is the upgrade path. 0.9 is vastely different from 0.8 so a special upgrade script has been written to aid with this. Now i have tested this on some gozerbot users but i need a more broader audience that wants to test this for me. So if you run a 0.8 gozerbot you could help me out with testing the 0.9 upgrade script, testing can be done along side your own bot so you dont loose your old configuration. To test do the following: 1) hg clone http://core.gozerbot.org/hg/dev/0.9 0.9bot 2) cd 0.9bot 3) hg clone http://core.gozerbot.org/hg/plugs/gozerplugs 4) ./bin/gozerbot-upgrade <oldbotdir> . 5) ./bin/gozerbot Check if the bot has converted your data properly with the !size command. As a last step you can test the plugins with the !test-plugs command. If you have any problems with testing gozerbot 0.9 let me know on #dunkbots IRCnet or at bthate(a)gmail.com .. THNX ;] Bart see http://gozerbot.org/newsite/0.9/ for more information about the upcoming 0.9 release

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Re: why cannot assign to function call
by Bruno Desthuilliers Jan. 2, 2009

Jan. 2, 2009

Derek Martin a écrit : > On Fri, Jan 02, 2009 at 11:43:30AM -0500, Steve Holden wrote: >> Derek Martin wrote: >>> What the Python community often overlooks, when this discussion again >>> rears its ugly head (as it seems to every other hour or so), is that >>> its assignment model is BIZARRE, as in it's conceptually different >>> from virtually all other languages substantially taught in >>> undergraduate computer science programs. And for that matter, it's >>> pretty unintuitive generally. >>> >> I'd definitely argue against bizarre. It's actually very easy to >> understand, and Python is by no means the only language to have used it. > > Clearly the first and third are true. :) But CS programs still > generally teach primarily C/C++, Java, and (some form of) assembly > AFAICT. A few odd ones pop up here and there along the way (I studied > with scheme, for example), but they vary and are highly > program-dependent. What the average CS grad sees is, AFAICT, still > very much what I described. Those languages also behave similarly to > what students see in mathematics (e.g. algebra etc.). With only that > to go on, Python seems rather weird, and I think from the frequency > with which these discussions occur on this list, clearly it *IS* > difficult for a neophyte Python programmer to understand the > assignment model. Took me about half an hour to grasp, not even being "CS grad" (nor whathever "grad" FWIW). By that time, I had a couple monthes working experience with VB, and had learned (but never seriously used) bits of C, C++, Java and Pascal.

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is there a way to determine a relative path to the script?
by tekion Jan. 2, 2009

Jan. 2, 2009

Hello, I have a script in /usr/local/app/mypython.py and a configuration file relative to /usr/local/app/conf. When I call the script with an absolute path of /usr/local/app/mypthon.py I recieved an error similar to the below error: Traceback (most recent call last): File "script/art/auditlog.py", line 28, in ? database = Config.get("DB", "user") File "/System/Library/Frameworks/Python.framework/Versions/2.3/lib/ python2.3/ConfigParser.py", line 505, in get raise NoSectionError(section) ConfigParser.NoSectionError: No section: 'DB' I know why, the configuration which I reference in the script is relative to "/usr/local/app", when I call the script via an absolute path, then the relative the configuration file is base on where ever I call the script from. One way to fix this is to add a path manually into the variable. But I would like to avoid this hard-coding parameter into my script. Is there a way to determined the relative location of the script programatically? FYI, in the end this scrip would run from CRON.

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Py2exe issue
by rcmn Jan. 2, 2009

Jan. 2, 2009

I'm using 2.6 (the issue was the same with 2.5) script.py: [code]import re from optparse import OptionParser parser = OptionParser() parser.add_option("-f", "--file", action="store", type="string", dest="filename") parser.add_option("-o", "--output", action="store", type="string", dest="fileout") (options, args) = parser.parse_args() from subprocess import Popen, PIPE if options.fileout: fileoutput = options.fileout output = open(fileoutput, "w") else: output = open("output.txt", "w") if options.filename: rawfile = options.filename file = open(rawfile) else: print "type -h for help" exit() from threading import Thread class Pinger(object): def __init__(self, hosts): for host in hosts: pa = PingAgent(host) pa.start() class PingAgent(Thread): def __init__(self, host): Thread.__init__(self) self.host = host def run(self): p = Popen('ping -n 1 ' + self.host, stdout=PIPE, stderr=True) m = re.search('Average = (.*)ms', p.stdout.read()) if m: output.write (self.host+",pingable\n") else: output.write (self.host+",not pingable\n") if __name__ == '__main__': pinglist = [] for line in file: pinglist.append(line.strip("\n")) Pinger(pinglist)[/code] py2exe setup.py : [code]from distutils.core import setup import py2exe, sys, os sys.argv.append('py2exe') setup( options = {'py2exe': {'bundle_files': 1}}, console = [{'script': "script.py"}], zipfile = None, ) [/code] error when the "script.exe" run [code]Exception in thread Thread-500 (most likely raised during interpreter shutdown): Traceback (most recent call last): File "threading.pyc", line 522, in __bootstrap_inner File "script.py", line 35, in run File "subprocess.pyc", line 588, in __init__ [/code] So the script.py run perfectly well under the py environment but if i use py2exe to make an exe then i get the error above. I read the note in the py2exe Fac regarding Popen, but i don't know if it's relevant in my case.

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Re: type conversion
by r Jan. 2, 2009

Jan. 2, 2009

On Jan 1, 4:40 pm, Robert Kern <robert.k...(a)gmail.com> wrote: > Hamish McKenzie wrote: > > sometimes I want to be able to initialize an instance with a variety of different data types. > > > as an obvious example I might want to initialize a 4x4 matrix with either 16 floats, a list/tuple or 16 floats, another matrix or a quaternion. > > > is there any other way to do it other than putting case statements in the __init__ method of the class, or having a Matrix.FromQuaternion( quat )? > > I recommend keeping the __init__() as dumb as possible. Ideally, it should just > assign to attributes. I would add a from<foo>() classmethod for each <foo> that > I wanted to support. If I really wanted an all-singing, all-dancing > initialization method, I would add another classmethod that would just dispatch > to the appropriate type-specific classmethod. I prefer classmethods to plain > functions because I can subclass. > > -- > Robert Kern > > "I have come to believe that the whole world is an enigma, a harmless enigma > that is made terrible by our own mad attempt to interpret it as though it had > an underlying truth." > -- Umberto Eco Why are you busting into this thread? why have you not created your own thread. Someone asked a question about recycle bin access and you come in here, bust down the door and ask a completely off topic question, which is OK if you start a new thread of your own. And the most insane part to all of this, is that Steven just plays right along?!?!? Come on Stevie, you know better than this! PS (To OP) mark hammonds win32 package will not do what you ask, sorry

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Re: If your were going to program a game...
by Fuzzyman Jan. 2, 2009

Jan. 2, 2009

On Jan 2, 6:16 pm, Jean-Paul Calderone <exar...(a)divmod.com> wrote: > On Fri, 2 Jan 2009 09:44:55 -0800 (PST), Fuzzyman <fuzzy...(a)gmail.com> wrote: > >On Jan 2, 3:02 pm, J Kenneth King <ja...(a)agentultra.com> wrote: > >> Tokyo Dan <huff...(a)tokyo.email.ne.jp> writes: > >> > If your were going to program a game in python what technologies would > >> > you use? > > >> > The game is a board game with some piece animations, but no movement > >> > animation...think of a chess king exploding. The game runs in a > >> > browser in a window of a social site built around the game. The social > >> > site has login, chat, player stats, list of active games, etc. AND > >> > there is also be a desktop client that accesses the game server via > >> > the same communication mechanism (like an AIR-based desktop client/ > >> > app) as the browser-based version - I guess using JSON/RPC. > > >> Ever see chess.com? > > >> I don't know what they're using in the backend, but the client is > >> entirely javascript. > > >> You could probably roll your own python javascript compiler to suit your > >> needs. It could probably even build up your own DSL for writing these > >> games. > > >> It's a worthwhile project and I think there might be support for it from > >> other developers. > > >There's a project called Pyjamas, and PyPy also has a Python to > >Javascript compiler. > > No, PyPy includes an RPython to JavaScript compiler. RPython and Python are > different languages. > Well valid RPython is valid Python - so different for some value of different... The advantage of PyPy is that it even does things like turn runtime exceptions into Python exceptions, so it should be much easier to debug. It is much more 'heavyweight' though. Michael Foord -- http://www.ironpythoninaction.com/

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Workshop "Medical Imaging Systems" within EUROMEDIA 2009 – Announce & Call for Papers
by tavares＠fe.up.pt Jan. 2, 2009

Jan. 2, 2009

-------------------------------------------------------------------------------------------------------------------------------------------- Workshop “Medical Imaging Systems” within EUROSIS EUROMEDIA 2009 April 15-17, 2009, Novotel, Bruges, Belgium http://www.eurosis.org/cms/?q=taxonomy/term/172 (Apologies for cross-posting. We would appreciate if you could distribute this information by your colleagues and co-workers.) -------------------------------------------------------------------------------------------------------------------------------------------- Dear Colleague, In recent years, extensive research has been performed to develop more and more efficient and powerful medical imaging systems. Such systems are crucial for medical specialists, allowing a deeper analysis and to understand what is going inside the human body, and therefore they play an essential role for adequate medical diagnosis and treatments. To accomplish efficient and powerful medical imaging systems, many research works have being done in many domains, like the ones related with medical image devices, signal processing, image processing and analysis, biomechanical simulation and data visualization. The main goal of the Workshop “Medical Imaging Systems” is to bring together researchers involved in the related domains, in order to set the major lines of development for the near future. Therefore, the proposed Workshop will consist of researchers representing various fields related to Medical Devices, Signal Processing, Computational Vision, Computer Graphics, Computational Mechanics, Scientific Visualization, Mathematics and Medical Imaging. The Workshop endeavors to contribute to obtain better solutions for more efficient and powerful medical imaging systems, and attempts to establish a bridge between clinicians and researchers from these diverse fields. Due to your research activities in the field, we would like to invite you to submit a contributed paper for the Workshop “Medical Imaging Systems”. Important Dates - Submission Deadline: January 20, 2009; - Notification of Acceptance or Rejection: March 20, 2009; - Authors provide camera-ready manuscript: April 15-17, 2009; - Conference Events: April 15-17, 2009. For further details please see the conference website at: http://www.eurosis.org/cms/?q=taxonomy/term/172 We are looking forward to see you in Bruges next April. Kind regards, João Manuel R. S. Tavares (University of Porto, tavares(a)fe.up.pt, www.fe.up.pt/~tavares)

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Re: FW: python import sys.path
by John Machin Jan. 2, 2009

Jan. 2, 2009

On Jan 3, 1:09 am, "Kelly, Brian" <Brian.Ke...(a)uwsp.edu> wrote: > After following your suggestions I was able to confirm that the 2.5 > interpreter was being invoked. So then I grepped for all instances of python > in the scripts that were imported as modules: from bacula_conf import * > > The calling script cleanup.py is invoking purge_client.py like an external > script: > > def purgeAll(options, computer_name): > cmd = "python purge_client.py %s" % computer_name > if options.pretend <> True: Who wrote that? > error = os.system(cmd) > else: > _log.info("Done. No changes made due to --pretend flag.") #### error is not defined in this branch > if not error: #### Splat! > return True > else: > return False AArrgh! Try: return not error > When I saw the imports I assumed the functions in purge_client.py were being > referenced from the calling scripts symbol table. What does that mean??

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