Re: Does turtle graphics have the wrong associations?
* Raymond Hettinger: On Nov 11, 10:21 pm, "Alf P. Steinbach" wrote: One reaction to http://preview.tinyurl.com/ProgrammingBookP3> has been that turtle graphics may be off-putting to some readers because it is associated with children's learning. What do you think? How about calling it Raptor Graphics that will please everyone ;-) He he. :-) import turtle as raptor raptor.shape( "triangle" ) def draw_poison_bush( level, angle, stem_length ): start_pos = raptor.pos() raptor.left( angle ) raptor.forward( stem_length ) if level > 0: draw_poison_bush( level-1, 30, 0.7*stem_length ) draw_poison_bush( level-1, 0, 0.85*stem_length ) draw_poison_bush( level-1, -37, 0.65*stem_length ) raptor.right( angle ) raptor.goto( start_pos ) raptor.title( "A DANGEROUS poison bush!" ) raptor.left( 90 ) raptor.back( 180 ) draw_poison_bush( 6, 0, 80 ) raptor.mainloop() Cheers, - Alf -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On 2009-11-12, at 23:19, Steven D'Aprano wrote: > On Thu, 12 Nov 2009 22:20:11 -0800, Vincent Manis wrote: > > Vincent, could you please fix your mail client, or news client, so > that it follows the standard for mail and news (that is, it has a > hard-break after 68 or 72 characters? My apologies. Will do. > Having to scroll horizontally to read your posts is a real pain. At least you're reading them. :) -- v-- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 22:20:11 -0800, Vincent Manis wrote: > When I was approximately 5, everybody knew that higher level languages were > too slow for high-speed numeric computation (I actually didn't know that > then, I was too busy watching Bill and Ben the Flowerpot Men), and therefore > assembly languages were mandatory. Then IBM developed Fortran, and > higher-level languages were not too slow for numeric computation. Vincent, could you please fix your mail client, or news client, so that it follows the standard for mail and news (that is, it has a hard-break after 68 or 72 characters? Having to scroll horizontally to read your posts is a real pain. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
On 2009-11-12, at 19:13, Peter Nilsson wrote: > My recollection is that many children struggled with Turtle > graphics because they had very little concept of trigonometry. > [Why would they? Many wouldn't learn for another 2-10 years.] > Adults tend to have even less concept since they almost never > use trig (or much else from school ;-) in the real world. > This paragraph is based upon a complete misunderstanding of turtle geometry. You do NOT use trigonometry to teach it, because the goal isn't to replicate cartesian geometry. The whole point about turtle geometry is that the student viscerally imagines him/herself BEING the turtle, and moving around the room according to the succession of FORWARD and TURNRIGHT commands. This is easier to visualize when one has an actual robot that draws pictures on butcher paper, as the second iteration of the MIT/BBN turtle work did (and they worked in middle schools, Grades 4-8, so there was no issue of trigonometry). > They can see the patterns and understand there's a logic to > it, but they struggle replicating it. Get an angle wrong > and you end up with a mess where it's not clear whether it's > your algorithm or the maths that's at fault. Kindly explain to me the difference between `algorithm' and `maths' here. I believe you just said that if there's a bug in the design, the program won't work. Hmmm. This reminds me of a well-known anecdote about the original LOGO study done at Muzzey High in Lexington, MA, in 1968. A group of NSF funding people was doing a tour of the school, and they came across a Grade 5 student who was doing a family tree program. The NSF people were impressed by the complexity of the program. One of them said in a patronizing tone, `I guess this stuff really helps you learn math'. She got quite angry, and responded, `This stuff has NOTHING to do with math!' > The visual aspect might pique interest, but may put just as > many people off. In any case, it won't relieve the difficulty > of having to teach what is fundamentally an abstraction that > doesn't have very good parallels with how people approach > problems in the real world. Humans simply don't think like > mathematicians^W computers. :-) Having taught grade 8 math, I can tell you that cartesian geometry is much LESS intuitive to people that are learning it than the relative polar coordinates of turtle geometry are. (`Oh, you want to get to the mall food court? Turn left, and walk past about 10 stores. The food court is right after the Gap.') > I've met a lot of mathematics and comp sci teachers who > honestly believe that you can't teach these subjects without > a mathematical perspective. That stands in contrast to the > number of people I see using spreadsheets with a very high > proficiency who would never dream of saying they were good > at mathematics or programming. It is true that you can't teach computer science to children without having a strong understanding of the mathematical foundations. It is also true that when you teach it to children that you very carefully hide the mathematical formalism. I might point out that the people who had most to do with the invention of turtle geometry were Wally Feurzeig (who was my boss when I worked at BBN in the 1970s) and Seymour Papert. Papert had spent a lot of time working with Jean Piaget in Switzerland. If you read the original LOGO memos, you will see his clear explanations on how this material ought to be taught to people with no math background, including children who are too young to do symbolic thinking (that kicks in in the early teens). That's why the visceral `I am a turtle' approach works well with middle-school kids. -- v > > -- > Peter > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
On Nov 11, 10:21 pm, "Alf P. Steinbach" wrote: > One reaction to http://preview.tinyurl.com/ProgrammingBookP3> has > been that turtle graphics may be off-putting to some readers because it is > associated with children's learning. > > What do you think? How about calling it Raptor Graphics that will please everyone ;-) Raymond -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
On Thu, Nov 12, 2009 at 8:10 PM, r wrote: > On Nov 12, 7:44 pm, Steven D'Aprano cybersource.com.au> wrote > > Oh, but those hundreds of thousands of man-hours lost to bugs caused by > > assignment-as-an-expression is nothing compared to the dozens of man- > > minutes saved by having one fewer line of code! > > OK, what *if* the variable would only be valid in *that* block and > *that* block only! My first idea was to have the variable avaiable in > the local scope (if that is correct terminology?) so if the > conditional was in global space the value would be available in global > space, alright? You follow me? Now forget all that and observe the > following. ;-) > > Assignment is a statement and not an expression in Python intentionally; its not just some random artifact. It was a decision. If you really want to overcome it, you need to show a SERIOUSLY huge amount of justification that goes far beyond 'hey, it saves me one line in certain situations'. You keep mentioning "elegant" and "clean" in the examples you've provided, but those terms (while often applied to Pythonisms) are very subjective. What you find elegant and clean, others may find prone to confusion or misunderstanding. There's a certain class of languages which treat assignments as expressions-- the C family most prominently. And some people love them and will forever seek it, as there is indeed a reduction of lines and/or code to express certain ideas if you use assignments as expressions. No one is really arguing against that. The argument against it is that it is extremely easy to screw up in ways which are extremely difficult to debug. > if value=range(10): > The problem with this is, its far too easy to type this but mean, "if value==range(10):" or some such. And then its far too hard to figure out why your program is wrong when it starts producing incorrect results. This has been a source of countless bugs over the years and years of C programming-- true, an excellent programmer will never make the mistake. But get some group of people together maintaining some codebase, and someone's gonna miss something, and others just will fail to see it as they scan over the code trying to figure out what's wrong. Granted, you can produce shorter and more concise code if you can make assignments expressions instead of statements. However, your code isn't anymore READABLE. And readability is more important then concise in Python, /on purpose/. It's true that you can usually produce a program in far fewer lines of Python code then you can in certain other languages not to be named; but that isn't the overriding goal. That's not a zen. There's no doctrine of, "Shorter is better". Readability counts is, though. The expression, "x=y" in a statement is far too easy to mess up with "x==y". You can try to do screwy things with the syntax like your original proposal of, "if x as y" to make it so a single missed = won't mess it up, but that doesn't really improve readability. It makes it less likely to accidentally screw things up, but also makes it very hard to scan code and determine where names are created and assigned to objects. Yeah, we use "as" in a few situations for assignment already. But those are all special constructs which stand on their own. Try/except, with, and import support it; but when scanning code those stand out on their own anyways, and none of them support arbitrarily complex expressions. The if statement does. The "as" can become lost within that expression, and when looking in the block of code you can easily miss where the binding occurs. The proposal that the variable exists only within the 'if' block is a non-starter; Python's namespaces don't work like that, they don't have arbitrary blocks of private variables. You just have your local, global, and builtin namespace (and static nested namespaces for closures)... changing that is a whole other can of worms, and this is not the proposal to do it. --S -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
On 2009-11-12, at 11:36, AK Eric wrote: > On Nov 12, 11:31 am, Terry Reedy wrote: >> Alf P. Steinbach wrote: >>> One reaction to >> http://preview.tinyurl.com/ProgrammingBookP3> has been that turtle >>> graphics may be off-putting to some readers because it is associated >>> with children's learning. Take a look at Abelson and diSessa's _Turtle Geometry: The Computer as a Medium for Exploring Mathematics_ (MIT Press, 1986). This is most definitely not a kids' book. Chapter titles include `Topology of Turtle Paths', `Piecewise Flat Surfaces', and `Curved Space and General Relativity'. As well as being a very nice 2D graphics API, turtles let you explore very deep math. Of course, they also let you explore cybernetics and feedback; see some of the old MIT AI Lab reports on LOGO for that (you can find them at MIT's CSAIL lab website). For a lot of that, you actually need a robot turtle, like perhaps a LEGO Mindstorms robot. Seymour Papert (who did a lot of the MIT LOGO work) was, before his terrible motor accident, in research chair endowed by...LEGO. Hmmm... :) Of course, some people don't like Python itself because they are afraid of snakes. > I used Turtle back on the Apple in the early 80's... so I personally > have very positive feelings towards it ;) To each their own eh? I did my master's thesis on LOGO about 10 years before that, and I have VERY warm and fuzzy feelings about turtles :) -- v -- http://mail.python.org/mailman/listinfo/python-list
Re: 3.x and 2.x on same machine (is this info at Python.org??)
On Nov 12, 1:52 pm, rantingrick wrote: > Hello, > > Currently i am using 2.6 on Windows and need to start writing code in > 3.0. I cannot leave 2.x yet because 3rd party modules are still not > converted. So i want to install 3.0 without disturbing my current > Python2.x. What i'm afraid of is that some SYSVARIABLE will get > changed to Python3.0 and when i double click a Python script it will > try and run Python 3.x instead of 2.x. I only want to run 3.0 scripts > from the command line... > python3.x myscript.py > > So how do i do this? Is my fear unfounded? Windows determines the double-click action based on the file extension. You just have to make sure that *.py files are associated with 2.x. http://support.microsoft.com/kb/307859 -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
On Nov 13, 10:28 am, hetchkay wrote: > On Nov 13, 9:50 am, John Yeung wrote: > > > > > On Nov 12, 11:22 pm, r wrote: > > > > On Nov 12, 10:07 pm, hetchkay wrote: > > > > I have the following in exit.py: > > > > import sys > > > > sys.exit(0) > > > > > I now try 'python -i exit.py': > > > > > In 2.5, the script exits as I would expect. > > > > > In 2.6, the following error is printed: > > > > > Traceback (most recent call last): > > > > File "exit.py", line 2, in > > > > sys.exit(0) > > > > SystemExit: 0 > > > > > I couldn't find anything related to this in "What's new in 2.6". > > > > Look here ;-) > > >http://docs.python.org/library/exceptions.html#exceptions.SystemExit > > > How does that answer the OP's question? Namely, how to make 2.6 > > behave like 2.5? (Even saying "You can't make 2.6 behave like 2.5" > > would have been a better answer.) > > > Failing that, how about something that explains why 2.6 behaves > > differently than 2.5, and why one of them is better or more correct > > than the other? > > > Personally, I think 2.6's is probably the more correct behavior. > > Specifically, if the point of the -i command line option is to force > > interactive mode after completion of the script (which in this case > > completed with sys.exit), then it should go to interactive mode > > regardless of whether the script terminates "normally" or not. I > > think 2.5's behavior of allowing interactive mode to be skipped is > > against the spirit of -i. Unless -i meant something different in 2.5. > > > Is there some kind of environment variable to set up to control this? > > > John > > I can understand the behavior from a '-i' point of view. My > requirement is somewhat different. Consider a geometry tool that can > be used to create objects, merge objects etc. I have python 'commands' > for doing any of these operations and for saving the objects to a > file. The user could write a file containing a set of commands (in > python format) and load this file in the GUI. Optionally, one of the > commands could be to exit in which case the GUI should shut down. I am > using 'execfile' to execute the file, and this does not exit if the > user has used sys.exit (or even if I expose a command called 'Exit' > which calls sys.exit). > > May be I should not be using execfile but I am not sure what else I > should use. The user-written file could contain loops and other > constructs as well. > > -Krishnan Hi, I had been starting my application with -i option. I have removed this now and made a few other changes and things work OK now. Thanks to everyone who helped in this. Regards, Krishnan -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
When I was approximately 5, everybody knew that higher level languages were too slow for high-speed numeric computation (I actually didn't know that then, I was too busy watching Bill and Ben the Flowerpot Men), and therefore assembly languages were mandatory. Then IBM developed Fortran, and higher-level languages were not too slow for numeric computation. When I was in university, IBM released a perfectly horrible implementation of PL/I, which dynamically allocated and freed stack frames for each procedure entry and exit (`Do Not Use Procedures: They Are Inefficient': section heading from the IBM PL/I (G) Programmer's Guide, circa 1968). Everyone knew PL/I was an abomination of a language, which could not be implemented efficiently. Then MIT/Bell Labs/GE/Honeywell wrote Multics in a PL/I subset, and (eventually) it ran quite efficiently. When Bell Labs pulled out of the Multics effort, some of their researchers wrote the first version of Unix in assembly language, but a few years later rewrote the kernel in C. Their paper reporting this included a sentence that said in effect, `yes, the C version is bigger and slower than the assembler version, but it has more functionality, so C isn't so bad'. Everybody knew that high-level languages were too inefficient to write an operating system in (in spite of the fact that Los Alamos had already written an OS in a Fortran dialect). Nobody knew that at about that time, IBM had started writing new OS modules in a company-confidential PL/I subset. When I was in grad school, everybody knew that an absolute defence to a student project running slowly was `I wrote it in Lisp'; we only had a Lisp interpreter running on our system. We didn't have MacLisp, which had been demonstrated to compile carefully-written numerical programs into code that ran more efficiently than comparable programs compiled by DEC's PDP-10 Fortran compiler in optimizing mode. In an earlier post, I mentioned SBCL and Chez Scheme, highly optimizing compiler-based implementations of Common Lisp and Scheme, respectively. I don't have numbers for SBCL, but I know that (again with carefully-written Scheme code) Chez Scheme can produce code that runs in the same order of magnitude as optimized C code. These are both very old systems that, at least in the case of Chez Scheme, use techniques that have been reported in the academic literature. My point in the earlier post about translating Python into Common Lisp or Scheme was essentially saying `look, there's more than 30 years experience building high-performance implementations of Lisp languages, and Python isn't really that different from Lisp, so we ought to be able to do it too'. All of which leads me to summarize the current state of things. 1. Current Python implementations may or may not be performance-scalable in ways we need. 2. Reorganized interpreters may give us a substantial improvement in performance. More significant improvements would require a JIT compiler, and there are good projects such as Unladen Swallow that may well deliver a substantial improvement. 3. We might also get improvements from good use of Python 3 annotations, or other pragma style constructs that might be added to the language after the moratorium, which would give a compiler additional information about the programmer's intent. (For example, Scheme has a set of functions that essentially allow a programmer to say, `I am doing integer arithmetic with values that are limited in range to what can be stored in a machine word'.) These annotations wouldn't destroy the dynamic nature of Python, because they are purely optional. This type of language feature would allow a programmer to exploit the high-performance compilation technologies that are common in the Lisp world. Even though points (2) and (3) between them offer a great deal of hope for future Python implementations, there is much that can be done with our current implementations. Just ask the programmer who writes a loop that laboriously does what could be done much more quickly with a list comprehension or with map. -- v -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
On Nov 13, 9:50 am, John Yeung wrote: > On Nov 12, 11:22 pm, r wrote: > > > > > On Nov 12, 10:07 pm, hetchkay wrote: > > > I have the following in exit.py: > > > import sys > > > sys.exit(0) > > > > I now try 'python -i exit.py': > > > > In 2.5, the script exits as I would expect. > > > > In 2.6, the following error is printed: > > > > Traceback (most recent call last): > > > File "exit.py", line 2, in > > > sys.exit(0) > > > SystemExit: 0 > > > > I couldn't find anything related to this in "What's new in 2.6". > > > Look here ;-) > >http://docs.python.org/library/exceptions.html#exceptions.SystemExit > > How does that answer the OP's question? Namely, how to make 2.6 > behave like 2.5? (Even saying "You can't make 2.6 behave like 2.5" > would have been a better answer.) > > Failing that, how about something that explains why 2.6 behaves > differently than 2.5, and why one of them is better or more correct > than the other? > > Personally, I think 2.6's is probably the more correct behavior. > Specifically, if the point of the -i command line option is to force > interactive mode after completion of the script (which in this case > completed with sys.exit), then it should go to interactive mode > regardless of whether the script terminates "normally" or not. I > think 2.5's behavior of allowing interactive mode to be skipped is > against the spirit of -i. Unless -i meant something different in 2.5. > > Is there some kind of environment variable to set up to control this? > > John I can understand the behavior from a '-i' point of view. My requirement is somewhat different. Consider a geometry tool that can be used to create objects, merge objects etc. I have python 'commands' for doing any of these operations and for saving the objects to a file. The user could write a file containing a set of commands (in python format) and load this file in the GUI. Optionally, one of the commands could be to exit in which case the GUI should shut down. I am using 'execfile' to execute the file, and this does not exit if the user has used sys.exit (or even if I expose a command called 'Exit' which calls sys.exit). May be I should not be using execfile but I am not sure what else I should use. The user-written file could contain loops and other constructs as well. -Krishnan -- http://mail.python.org/mailman/listinfo/python-list
Re: regex remove closest tag
On Fri, Nov 13, 2009 at 12:47 AM, MRAB wrote:
> S.Selvam wrote:
>
>> Hi all,
>>
>>
>> 1) I need to remove the tags which is just before the keyword(i.e
>> some_text2 ) excluding others.
>>
>> 2) input string may or may not contain tags.
>>
>> 3) Sample input: inputstr = """start > href="some_url">some_text1 some_text2 keyword anything"""
>>
>> 4) I came up with the following regex,
>>
>>
>> p=re.compile(r'(?P.*?)(\s*keyword|\s*keyword)(?P.*)',re.DOTALL|re.I)
>> s=p.search(inputstr)
>> but second group matches both tags,while i need to match the recent
>> one only.
>>
>> I would like to get your suggestions.
>>
>> Note:
>>
>> If i leave group('good1') as greedy, then it matches both the tag.
>>
>> ".*?" can match any number of any character, so it can match any
> intervening "" tags. Try "[^<]*?" instead.
>
>
Thanks a lot,
p=re.compile(r'(?:\s*%s)'%(keyword),re.I|re.S) has done
it !
--
> http://mail.python.org/mailman/listinfo/python-list
>
--
Yours,
S.Selvam
--
http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
On Nov 12, 6:29 pm, greg wrote: > I would be taking a different approach -- develop a prototype > in Python, concentrating on clarity rather than speed, and > later reimplement the core of the emulator as an extension > module, using Pyrex or Cython or otherwise. But keep in mind he said he was doing it just for fun. I don't know about you, but I find it much more fun to try to write fast Python than to write the fast stuff in C. Not as effective, but more fun. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
In article <008aa7ef-b945-4f70-b5e4-def66546e...@2g2000prl.googlegroups.com>, hetchkay wrote: > I have the following in exit.py: > import sys > sys.exit(0) > > I now try 'python -i exit.py': > > In 2.5, the script exits as I would expect. > > In 2.6, the following error is printed: > > Traceback (most recent call last): > File "exit.py", line 2, in > sys.exit(0) > SystemExit: 0 > >>> > > I couldn't find anything related to this in "What's new in 2.6". > > Is there any way I can get 2.6 to behave like 2.5? Perhaps you don't want to be using the -i option? "-i When a script is passed as first argument or the -c option is used, enter interactive mode after executing the script or the command ..." http://docs.python.org/using/cmdline.html#generic-options If you don't want the interpreter to gain control on exit, don't use -i when you run the script. -- Ned Deily, n...@acm.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
On Nov 12, 6:37 am, Santiago Romero wrote: > > > I'm trying to port (just for fun), my old Sinclair Spectrum emulator, > > > ASpectrum, from C to Python + pygame. > > > The answer to your question is, "Use numpy". More details below. > > Let's see :-) > > > > How can I implement this in Python, I mean, define a 16 byte variable > > > so that high and low bytes can be accessed separately and changing W, > > > H or L affects the entire variable? I would like to avoid doing BIT > > > masks to get or change HIGH or LOW parts of a variable and let the > > > compiled code to do it by itself. > > > You can do clever memory slicing like this with numpy. For instance: > > > breg = numpy.zeros((16,),numpy.uint8) > > wreg = numpy.ndarray((8,),numpy.uint16,breg) > > > This causes breg and wreg to share the same 16 bytes of memory. You > > can define constants to access specific registers: > > > R1L = 1 > > R1H = 2 > > R1 = 1 > > > breg[R1H] = 2 > > print wreg[R1] > > And how about speed? > > Assuming a 16 bit register named BC which contains 2 8 bit regiters (B > and C)... > > Will the above be faster than shifts and bit operations (<<, and,>> ) with > new B and C values to "recalculate" BC when reading or > > changing either B, C or BC? I don't know. Strange thing about Python, the community generally isn't hellbent on speed so we don't usually memorize a bunch of facts like "X is faster than Y". I'm personally aware of only a few general rules of thumb on speed (like "local variables are much faster than globals" and "function calls have rather high overhead"). Obviously, given the problem you chose, you know you're going to have to worry about speed from the beginning. But since not many of us know speed details off-hand, you'll probably get a faster answer by just running the speed tests yourself. Having said that, I *suspect* the numpy approach I mentioned will be quite a bit faster than using bit operations and recalculating BC, but I really don't know. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
On Nov 12, 11:32 pm, hetchkay wrote: > But I don't understand why the interpreter does not exit in 2.6 but > does exit in 2.5. Well, I do not need to understand that but I need to > know how to get the interpreter to exit in 2.6. Well, taken at face value, I would say the answer is to not use the -i option. ;) But I assume you would like to be able to sometimes enter interactive mode after the script completes but sometimes not? That I don't know how to do, but I would think it is either very simple or impossible. Surely someone more knowledgeable will be able to say which it is. Also, if you present your reason for wanting such behavior, maybe people can suggest alternatives that will serve your needs, even if not exactly replicating what you had in 2.5. John -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
On Nov 12, 11:22 pm, r wrote: > On Nov 12, 10:07 pm, hetchkay wrote: > > I have the following in exit.py: > > import sys > > sys.exit(0) > > > I now try 'python -i exit.py': > > > In 2.5, the script exits as I would expect. > > > In 2.6, the following error is printed: > > > Traceback (most recent call last): > > File "exit.py", line 2, in > > sys.exit(0) > > SystemExit: 0 > > > I couldn't find anything related to this in "What's new in 2.6". > > Look here ;-) > http://docs.python.org/library/exceptions.html#exceptions.SystemExit How does that answer the OP's question? Namely, how to make 2.6 behave like 2.5? (Even saying "You can't make 2.6 behave like 2.5" would have been a better answer.) Failing that, how about something that explains why 2.6 behaves differently than 2.5, and why one of them is better or more correct than the other? Personally, I think 2.6's is probably the more correct behavior. Specifically, if the point of the -i command line option is to force interactive mode after completion of the script (which in this case completed with sys.exit), then it should go to interactive mode regardless of whether the script terminates "normally" or not. I think 2.5's behavior of allowing interactive mode to be skipped is against the spirit of -i. Unless -i meant something different in 2.5. Is there some kind of environment variable to set up to control this? John -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
Hello, Thanks for your help. I know what SystemExit is. In 2.5 as well SystemExit is raised when sys.exit() is called. For example: try: import sys sys.exit(0) except SystemExit: print "system exit raised" raise But I don't understand why the interpreter does not exit in 2.6 but does exit in 2.5. Well, I do not need to understand that but I need to know how to get the interpreter to exit in 2.6. Regards, Krishnan -- http://mail.python.org/mailman/listinfo/python-list
how to install python-spidermonkey on windows
Hello all, im making some script with python mechanize, one of problem is it really hard to find which support javascript supported web client scraping or crawler. actually i was found some such as python-spidermonkey and pykhtml and so on. but most of all only support on linux . i want to make my python script with exe file. so definitely i have to install on windows platform. my question is ..are there any method to can install python-spidermonkey or pykhtml on windows platform? i really need to support windows platform. if anyone can hint or help really appreicate! thanks in advance Paul -- View this message in context: http://old.nabble.com/how-to-install-python-spidermonkey-on-windows-tp26331307p26331307.html Sent from the Python - python-list mailing list archive at Nabble.com. -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
PS: Python even answers questions: >>> import sys >>> help(sys.exit) Help on built-in function exit in module sys: exit(...) exit([status]) Exit the interpreter by raising SystemExit(status). If the status is omitted or None, it defaults to zero (i.e., success). If the status is numeric, it will be used as the system exit status. If it is another kind of object, it will be printed and the system exit status will be one (i.e., failure). Just think of Python as a programmers version of the "Magic 8 balls". -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 and sys.exit()
On Nov 12, 10:07 pm, hetchkay wrote: > Hello, > > I have the following in exit.py: > import sys > sys.exit(0) > > I now try 'python -i exit.py': > > In 2.5, the script exits as I would expect. > > In 2.6, the following error is printed: > > Traceback (most recent call last): > File "exit.py", line 2, in > sys.exit(0) > SystemExit: 0 > > > > I couldn't find anything related to this in "What's new in 2.6". Look here ;-) http://docs.python.org/library/exceptions.html#exceptions.SystemExit -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
On Nov 12, 7:44 pm, Steven D'Aprano wrote > Oh, but those hundreds of thousands of man-hours lost to bugs caused by > assignment-as-an-expression is nothing compared to the dozens of man- > minutes saved by having one fewer line of code! OK, what *if* the variable would only be valid in *that* block and *that* block only! My first idea was to have the variable avaiable in the local scope (if that is correct terminology?) so if the conditional was in global space the value would be available in global space, alright? You follow me? Now forget all that and observe the following. ;-) if value=range(10): #this block *would* execute and "value" would be a valid name #but only IN this block!!! value.append(1) elif value=fetch(0): #this block would *never* execute value.append(1) value.append(1) -> this throws a NameError Is that different than how other languages handle "assignment-by- expression"? Will that avoid the cataclysmic downward spiral you speak of? I can't see any problems with it AND it can still be applied to myself and Carl's use cases. Anybody is welcome to comment...? -- http://mail.python.org/mailman/listinfo/python-list
2.6 and sys.exit()
Hello, I have the following in exit.py: import sys sys.exit(0) I now try 'python -i exit.py': In 2.5, the script exits as I would expect. In 2.6, the following error is printed: Traceback (most recent call last): File "exit.py", line 2, in sys.exit(0) SystemExit: 0 >>> I couldn't find anything related to this in "What's new in 2.6". Is there any way I can get 2.6 to behave like 2.5? Thank you for your help, Regards, H. Krishnan -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: esky 0.2.1
> >Esky is an auto-update framework for frozen python apps, built on top of > >bbfreeze. It provides a simple API through which apps can find, fetch > >and install updates, and a bootstrapping mechanism that keeps the app > >safe in the face of failed or partial updates. > > Recently I was looking into distribution mechanisms, and I passed over > bbfreeze because I saw no indication that Python 2.6 was supported. Not sure if it's officially supported, but I do most of my development on Python 2.6 and bbfreeze hasn't given me any problems as yet. Cheers, Ryan -- Ryan Kelly http://www.rfk.id.au | This message is digitally signed. Please visit r...@rfk.id.au| http://www.rfk.id.au/ramblings/gpg/ for details signature.asc Description: This is a digitally signed message part -- http://mail.python.org/mailman/listinfo/python-list
Re: python parser overridden by pymol
Robert Kern wrote:
Jeremiah
H. Savage wrote:
To use pymol and numpy together, I now do the following:
To ~/.bashrc add:
PYMOL_PATH=/usr/lib/pymodules/python2.5/pymol
export PYMOL_PATH
Then I can do the following in python:
import numpy
numpy.save('123',numpy.array([1,2,3]))
numpy.load('123.npy')
array([1, 2, 3])
import sys
sys.path.append( "/usr/lib/pymodules/python2.5/pymol")
import pymol
pymol.finish_launching()
pymol.importing.load("/path/to/file.pdb")
No, do not do this. Add /usr/lib/pymodules/python2.5/ to your
$PYTHONPATH, *not* /usr/lib/pymodules/python2.5/pymol/. You will
continue to run into problems if you do it this way. You are not
supposed to put the directory *of* the package onto sys.path but
rather the directory that *contains* the package directory.
As I said before, I don't know pymol. But if that is the package name,
then Robert is certainly right. You need to read the docs on pymol to
see what they require. For example, it's surprising they require a
separate PYMOL_PATH environment variable, since they can find their own
directory path with the __file__ attribute of one of the modules.
Anyway, one more generic comment. Rather than having that directory in
both the bashrc file AND in your python source, I'd consider deriving
the latter from the environment variable, once you determine that it's
actually necessary. And of course you could strip the last node from
the path in the environment variable before appending it to sys.path, if
that's what's appropriate.
DaveA
--
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Python 2.6 and sys.exit()
Hello, I have the following in exit.py: import sys sys.exit(0) I now try 'python -i exit.py': In 2.5, the script exits as I would expect. In 2.6, the following error is printed: Traceback (most recent call last): File "exit.py", line 2, in sys.exit(0) SystemExit: 0 >>> I couldn't find anything related to this in "What's new in 2.6". Is there any way I can get 2.6 to behave like 2.5? Thank you for your help, Regards, H. Krishnan -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: esky 0.2.1
In article , Ryan Kelly wrote: > >Esky is an auto-update framework for frozen python apps, built on top of >bbfreeze. It provides a simple API through which apps can find, fetch >and install updates, and a bootstrapping mechanism that keeps the app >safe in the face of failed or partial updates. Recently I was looking into distribution mechanisms, and I passed over bbfreeze because I saw no indication that Python 2.6 was supported. Kind of a bummer because esky looks pretty cool. -- Aahz (a...@pythoncraft.com) <*> http://www.pythoncraft.com/ [on old computer technologies and programmers] "Fancy tail fins on a brand new '59 Cadillac didn't mean throwing out a whole generation of mechanics who started with model As." --Andrew Dalke -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
"Alf P. Steinbach" wrote: > One reaction to http://preview.tinyurl.com/ProgrammingBookP3> has > been that turtle graphics may be off-putting to some > readers because it is associated with children's learning. [I'll be honest and say that I merely glanced at the two pdf files.] Who is your target audience? The opening Getting Started paragraph would probably put off many beginners right from the get go! You're talking about a 'first language' but throwing 'syntax', 'windows', 'graphics', 'networking', 'file and database access' and 'standard libraries' at them. The success of ' for Dummies' is certainly not their accuracy, but rather that they make far fewer assumptions that people already know the subject being tought! That assumption seems almost ingrained in every 'beginner' programming book I've ever seen! > What do you think? Whilst everyone knows children tend to think visually more than abstractly, the same is precisely true of adults. However, the ultimate problem with Turtle is that it ends up teaching a 'mathematical' perspective and it's far from intuitive how you map that perspective to tackling more real world issues. It's simply substituting one difficult abstraction with another. My recollection is that many children struggled with Turtle graphics because they had very little concept of trigonometry. [Why would they? Many wouldn't learn for another 2-10 years.] Adults tend to have even less concept since they almost never use trig (or much else from school ;-) in the real world. They can see the patterns and understand there's a logic to it, but they struggle replicating it. Get an angle wrong and you end up with a mess where it's not clear whether it's your algorithm or the maths that's at fault. The visual aspect might pique interest, but may put just as many people off. In any case, it won't relieve the difficulty of having to teach what is fundamentally an abstraction that doesn't have very good parallels with how people approach problems in the real world. Humans simply don't think like mathematicians^W computers. :-) I've met a lot of mathematics and comp sci teachers who honestly believe that you can't teach these subjects without a mathematical perspective. That stands in contrast to the number of people I see using spreadsheets with a very high proficiency who would never dream of saying they were good at mathematics or programming. -- Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
On Fri, 13 Nov 2009 15:33:53 +1300, greg wrote:
> Santiago Romero wrote:
>>>How about
>>>page, index = divmod(address, 16384)
>>
>> Surely, much better and faster :-)
>
> Not necessarily, because it involves a function call, and constructing
> and deconstructing a result tuple. If you time them, you may well find
> that the explicit shift and mask operations turn out to be faster.
It's easy enough to test:
>>> from timeit import Timer
>>> t1 = Timer('a = n>>14; b = n & 16384', 'n=2137902')
>>> t2 = Timer('a,b = divmod(n, 16384)', 'n=2137902')
>>> min(t1.repeat(repeat=5))
0.32850909233093262
>>> min(t2.repeat(repeat=5))
0.54839301109313965
The shift and mask are a little faster on my machine, but that's
certainly what I would call a micro-optimization. Unless the divmod call
is the bottleneck in your code -- and it almost certainly won't be -- I
don't think it's worth the obfuscation to use shift/mask. What should be
done is write the code in the clearest way you can, then, only if it is
it too slow, profile it to see where it actually needs optimizing.
--
Steven
--
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Re: Python & Go
Duncan Booth writes: > > http://scienceblogs.com/goodmath/2009/11/googles_new_language_go.php > > > Thanks for that link. I think it pretty well agrees with my first > impressions of Go: It looks like a not-so-interesting C follow-on, but the article doesn't describe any of the parallelism stuff. > The lack of any kind of error handling, whether exceptions or > anything else is, I think, a killer. When you access a value out of > a map you have a choice of syntax: one way gives you a boolean flag > you can test to see whether or not the item was in the map, the > other either gives you the value or crashes the program (yes, the > documentation actually says 'crash'). Both of these are wrong: the > flag is wrong because it forces you to handle every lookup error > immediately and at the same place in the code; the crash is wrong > for obvious reasons. Nah, exceptions are an ugly effect that gets in the way of parallelism. Haskell handles lookups through its type system; dealing with lookup errors (say by chaining the Maybe type) is clean and elegant. Erlang handles it by crashing the process, and dealing with the crash through a supervision tree that cleans up after crashes and restarts the crashed processes. > What that article didn't mention, and what is possibly Go's real strong > point is that it has built-in support for parallel processing. Again though > the implementation looks weak... I'd like to know more about this; is there a link with a short write-up? I haven't gotten around to looking at the reference materials. > It has too many special cases: a lot of the builtin types can exist > only as builtin types: if they weren't part of the language you > couldn't implement an equivalent. I'd also like to have seen a more serious type system, like ML's or better. But they seemed to really be after a fast, lightweight compiler. Anyway, it doesn't like even slightly intended to be in the same space as Python. It's more like a de-bureaucratized replacement for Java. -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
On Fri, 13 Nov 2009 15:29:03 +1300, greg wrote: > Generally, I think you're going to have quite a battle on your hands to > get a pure Python implementation to run as fast as a real Z80, if it's > even possible at all. And if you do succeed, the code will be pretty > awful (due to things such as not being able to use named constants). I don't know about that... Python on a 2GHz processor (which is more or less entry-level for desktop PCs these days), emulating something which used to run at 2.5MHz? Even if the Python code does 1000 times more work, the modern processor is nearly 1000 times faster, so your Python code won't be much slower than the first generation Z80. The latest Z80 processors operate at 50MHz. That still gives you a factor of 40 to work with. Write your Python carefully, optimizing only the bits that *need* optimizing, and perhaps using a few C extensions or Psyco, and I think you have a good chance of being close enough to the speed of a real Z80. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 21:02:11 +0100, Alf P. Steinbach wrote:
> Specifically, I reacted to the statement that < talk about "the" speed of an implementation>>, made in response to
> someone upthread, in the context of Google finding CPython overall too
> slow.
>
> It is quite slow. ;-)
Quite slow to do what? Quite slow compared to what?
I think you'll find using CPython to sort a list of ten million integers
will be quite a bit faster than using bubblesort written in C, no matter
how efficient the C compiler.
And why are we limiting ourselves to integers representable by the native
C int? What if the items in the list were of the order of 2**10? Of
if they were mixed integers, fractions, fixed-point decimals, and
floating-point binaries? How fast is your C code going to be now? That's
going to depend on the C library you use, isn't it? In other words, it is
an *implementation* issue, not a *language* issue.
Okay, let's keep it simple. Stick to numbers representable by native C
ints. Around this point, people start complaining that it's not fair, I'm
not comparing apples with apples. Why am I comparing a highly-optimized,
incredibly fast sort method in CPython with a lousy O(N**2) algorithm in
C? To make meaningful comparisons, you have to make sure the algorithms
are the same, so the two language implementations do the same amount of
work. (Funnily enough, it's "unfair" to play to Python's strengths, and
"fair" to play to C's strengths.)
Then people invariable try to compare (say) something in C involving low-
level bit-twiddling or pointer arithmetic with something in CPython
involving high-level object-oriented programming. Of course CPython is
"slow" if you use it to do hundreds of times more work in every operation
-- that's comparing apples with oranges again, but somehow people think
that's okay when your intention is to prove "Python is slow".
An apples-to-apples comparison would be to use a framework in C which
offered the equivalent features as Python: readable syntax ("executable
pseudo-code"), memory management, garbage disposal, high-level objects,
message passing, exception handling, dynamic strong typing, and no core
dumps ever.
If you did that, you'd get something that runs much closer to the speed
of CPython, because that's exactly what CPython is: a framework written
in C that provides all those extra features.
(That's not to say that Python-like high-level languages can't, in
theory, be significantly faster than CPython, or that they can't have JIT
compilers that emit highly efficient -- in space or time -- machine code.
That's what Psyco does, now, and that's the aim of PyPy.)
However, there is one sense that Python *the language* is slower than
(say) C the language. Python requires that an implementation treat the
built-in function (say) int as an object subject to modification by the
caller, while C requires that it is a reserved word. So when a C compiler
sees "int", it can optimize the call to a known low-level routine, while
a Python compiler can't make this optimization. It *must* search the
entire scope looking for the first object called 'int' it finds, then
search the object's scope for a method called '__call__', then execute
that. That's the rules for Python, and an implementation that does
something else isn't Python. Even though the searching is highly
optimized, if you call int() one million times, any Python implementation
*must* perform that search one million times, which adds up. Merely
identifying what function to call is O(N) at runtime for Python and O(1)
at compile time for C.
Note though that JIT compilers like Psyco can often take shortcuts and
speed up code by a factor of 2, or up to 100 in the best cases, which
brings the combination of CPython + Psyco within shouting distance of the
speed of the machine code generated by good optimizing C compilers. Or
you can pass the work onto an optimized library or function call that
avoids the extra work. Like I said, there is no reason for Python
*applications* to be slow.
--
Steven
--
http://mail.python.org/mailman/listinfo/python-list
Re: #define (from C) in Python
TerryP wrote: If it's such a big hairy deal, just recompile a copy of the C Pre Processor to use something other then #, and hook it up to your python scripts in a pipe line from a shell wrapper. Or use a different preprocessor, such as m4, that doesn't clash with the # character. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: python parser overridden by pymol
Jeremiah H. Savage wrote:
To use pymol and numpy together, I now do the following:
To ~/.bashrc add:
PYMOL_PATH=/usr/lib/pymodules/python2.5/pymol
export PYMOL_PATH
Then I can do the following in python:
import numpy
numpy.save('123',numpy.array([1,2,3]))
numpy.load('123.npy')
array([1, 2, 3])
import sys
sys.path.append( "/usr/lib/pymodules/python2.5/pymol")
import pymol
pymol.finish_launching()
pymol.importing.load("/path/to/file.pdb")
No, do not do this. Add /usr/lib/pymodules/python2.5/ to your $PYTHONPATH, *not*
/usr/lib/pymodules/python2.5/pymol/. You will continue to run into problems if
you do it this way. You are not supposed to put the directory *of* the package
onto sys.path but rather the directory that *contains* the package directory.
--
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
--
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Re: Writing an emulator in python - implementation questions (for performance)
Santiago Romero wrote: How about page, index = divmod(address, 16384) Surely, much better and faster :-) Not necessarily, because it involves a function call, and constructing and deconstructing a result tuple. If you time them, you may well find that the explicit shift and mask operations turn out to be faster. That also goes for any of the other things being discussed here. Especially if you're used to C, one's intuitions about speed can go badly astray where Python is concerned. The only way to be sure is to measure! -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
Carl Banks wrote: You can define constants to access specific registers: R1L = 1 R1H = 2 R1 = 1 breg[R1H] = 2 print wreg[R1] But keep in mind that named "constants" at the module level are really global variables, and therefore incur a dictionary lookup every time they're used. For maximum speed, nothing beats writing the numeric literals directly into the code, unfortunately. Generally, I think you're going to have quite a battle on your hands to get a pure Python implementation to run as fast as a real Z80, if it's even possible at all. And if you do succeed, the code will be pretty awful (due to things such as not being able to use named constants). I would be taking a different approach -- develop a prototype in Python, concentrating on clarity rather than speed, and later reimplement the core of the emulator as an extension module, using Pyrex or Cython or otherwise. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: python with echo
Steven D'Aprano wrote: On Thu, 12 Nov 2009 19:30:01 +, MRAB wrote: I don't understand that. Exit status codes on all systems I'm familiar with are limited to 0 through 255. What operating system are you using? Assuming your system allows two-byte exit statuses, you should check the documentation for echo and the shell to see why it is returning 256. In some OSs the exit status consists of 2 fields, one being the child process's exit status and the other being supplied by the OS. Which OSes? The reason is simple. What if the child process terminated abnormally? You'd like an exit status to tell you that, Which it does. Anything other than 0 is an error. I see that, for example, if I interrupt "sleep 30" with ctrl-C instead of waiting for it to exit normally, it returns with an exit status of 130. [st...@soy ~]$ sleep 3 # no interrupt [st...@soy ~]$ echo $? 0 [st...@soy ~]$ sleep 3 # interrupt with ctrl-C [st...@soy ~]$ echo $? 130 I get the same result on a Linux box and a Solaris box, both running bash. but you wouldn't want it to be confused with the child process's own exit status, assuming that it had terminated normally. I don't understand what you mean here. Why are you assuming it terminated normally if it terminated abnormally? You want to be able to distinguish between a child process terminating with an exit status, and failing to run a child process for some reason. -- http://mail.python.org/mailman/listinfo/python-list
Re: QuerySets in Dictionaries
On Thu, 12 Nov 2009 10:39:33 -0800, scoopseven wrote:
> I need to create a dictionary of querysets. I have code that looks
> like:
>
> query1 = Myobject.objects.filter(status=1)
> query2 = Myobject.objects.filter(status=2)
> query3 = Myobject.objects.filter(status=3)
>
> d={}
> d['a'] = query1
> d['b'] = query2
> d['c'] = query3
>
> Is there a way to do this that I'm missing?
I don't understand your problem. Assuming Myobject is defined, and has
the appropriate attribute objects.filter, the above should work exactly
as you give it.
What is your actual problem? Are you asking for help in defining a
queryset?
--
Steven
--
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Re: open source linux -> windows database connectivity?
>Note: The client part of this product is free. You only need to >get a license for the server part. Yeah, but don't I need the server part to make the connection? Would it be possible to use Jython and the Pervasive JDBC driver for this? On Nov 12, 2:56 pm, "M.-A. Lemburg" wrote: > Tony Schmidt wrote: > > I am trying to read a Pervasive database on a Windows machine from a > > Python script on a Linux machine. > > > I understand that this can be done with a proprietary ODBC-to-ODBC > > bridge called mxODBC or Easysoft OOB. > > The product is called "mxODBC Connect" and allows connecting from > Python (running on pretty much any major platform) to a Windows > or Linux server running the database: > > http://www.egenix.com/products/python/mxODBCConnect/ > > Note: The client part of this product is free. You only need to > get a license for the server part. > > Alternatively, you can also our mxODBC single-tier product with > the Pervasive ODBC driver available for Linux: > > http://ww1.pervasive.com/developerzone/platforms/linux.asp > > Regards, > -- > Marc-Andre Lemburg > eGenix.com > > Professional Python Services directly from the Source (#1, Nov 12 2009)>>> > Python/Zope Consulting and Support ... http://www.egenix.com/ > >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ > >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ > > > > ::: Try our new mxODBC.Connect Python Database Interface for free ! > > eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 > D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg > Registered at Amtsgericht Duesseldorf: HRB 46611 > http://www.egenix.com/company/contact/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python with echo
On Thu, 12 Nov 2009 19:30:01 +, MRAB wrote: >> I don't understand that. Exit status codes on all systems I'm familiar >> with are limited to 0 through 255. What operating system are you using? >> >> Assuming your system allows two-byte exit statuses, you should check >> the documentation for echo and the shell to see why it is returning >> 256. >> > In some OSs the exit status consists of 2 fields, one being the child > process's exit status and the other being supplied by the OS. Which OSes? > The reason is simple. What if the child process terminated abnormally? > You'd like an exit status to tell you that, Which it does. Anything other than 0 is an error. I see that, for example, if I interrupt "sleep 30" with ctrl-C instead of waiting for it to exit normally, it returns with an exit status of 130. [st...@soy ~]$ sleep 3 # no interrupt [st...@soy ~]$ echo $? 0 [st...@soy ~]$ sleep 3 # interrupt with ctrl-C [st...@soy ~]$ echo $? 130 I get the same result on a Linux box and a Solaris box, both running bash. > but you wouldn't want it to > be confused with the child process's own exit status, assuming that it > had terminated normally. I don't understand what you mean here. Why are you assuming it terminated normally if it terminated abnormally? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
On Thu, 12 Nov 2009 21:27:31 +0100, Bruno Desthuilliers wrote: > Congratulations, you just reinvented one of the most infamous source of > bugs in C, C++, Java, PHP, javascript and quite a few other languages. > Believe it or not, but not allowing this in Python was a very deliberate > design choice. Oh, but those hundreds of thousands of man-hours lost to bugs caused by assignment-as-an-expression is nothing compared to the dozens of man- minutes saved by having one fewer line of code! *wink* -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Linux, Python 2.5.2, serverless binding LDAP?
On Nov 12, 8:01 pm, alex23 wrote: > On Nov 13, 10:47 am, Kevin Cole wrote: > > > > > Hi, > > > I recently asked our IT department how to gain access to an > > addressbook. After carefully explaining that I was on a Linux system > > using Python, I got the reply: > > > "You should use our LDAP. With LDAP you can pull any data you want > > from Active Directory. On our network, the serverless binding address > > for our LDAP is ldap://dc=...,dc=...,dc=...,dc=..."; > > > with the actual "..." filled in. > > > I don't know squat about LDAP, but installed the python-ldap deb, and > > started glancing at the documentation on-line. I didn't see anything > > obvious for working with the URI above. Can I work w/ it? If so, a > > short example, please? > > > Thanx. > > http://www.python-ldap.org/doc/html/ldapurl.html#example On second thought... That didn't help at all. The example just shows how to parse a URI. I'm trying to connect to a service (if I understand correctly) that is NOT on my Linux box, but somewhere out in our IT department's ether, and I do not have host/domain to work with. I interpreted "serverless binding" to mean that I was connecting by some means other than host.domain:port. Yes? -- http://mail.python.org/mailman/listinfo/python-list
Re: python parser overridden by pymol
On Wed, Nov 11, 2009 at 7:48 PM, Dave Angel wrote:
>
>
> Jeremiah wrote:
>>
>> Hello,
>>
>> I'm fairly new to python (version 2.5.4), and am writing a program
>> which uses both pymol (version 1.2r1) and numpy (version 1.3.0) from
>> debian.
>>
>> It appears that when I add pymol to $PYTHONPATH, that parser.expr() is
>> no longer available, and so I am unable to use numpy.load(). I have
>> looked for where parser.expr() is defined in the python system so I
>> could place that directory first in $PYTHONPATH, but I have not been
>> able to find the file that defines expr().
>>
>> My reason for using numpy.load() is that I have a numpy array which
>> takes an hour to generate. Therefore, I'd like to use numpy.save() so
>> I could generate the array one time, and then load it later as needed
>> with numpy.load().
>>
>> I've successfully tested the use of numpy.save() and numpy.load() with
>> a small example when the pymol path is not defined in $PYTHONPATH :
>>
>> >>> import numpy
>> >>> numpy.save('123',numpy.array([1,2,3]))
>> >>> numpy.load('123.npy')
>> array([1, 2, 3])
>>
>>
>> However, a problem arises once $PYTHONPATH includes the pymol
>> directory. To use the pymol api, I add the following to ~/.bashrc:
>>
>> PYMOL_PATH=/usr/lib/pymodules/python2.5/pymol
>> export PYMOL_PATH
>> PYTHONPATH=$PYMOL_PATH
>> export PYTHONPATH
>>
>> Once this is done, numpy.load() no longer works correctly, as pymol
>> contains a file named parser.py ( /usr/lib/pymodules/python2.5/pymol/
>> parser.py ), which apparently prevents python from using its native
>> parser.
>>
>> >>> numpy.load('123.npy')
>> Traceback (most recent call last):
>> File "", line 1, in
>> File "/usr/lib/python2.5/site-packages/numpy/lib/io.py", line
>> 195, in load
>> return format.read_array(fid)
>> File "/usr/lib/python2.5/site-packages/numpy/lib/format.py",
>> line 353, in read_array
>> shape, fortran_order, dtype = read_array_header_1_0(fp)
>> File "/usr/lib/python2.5/site-packages/numpy/lib/format.py",
>> line 250, in read_array_header_1_0
>> d = safe_eval(header)Thank you. That really helped.
To use pymol and numpy to
>> File "/usr/lib/python2.5/site-packages/numpy/lib/utils.py", line
>> 840, in safe_eval
>> ast = compiler.parse(source, "eval")
>> File "/usr/lib/python2.5/compiler/transformer.py", line 54, in
>> parse
>> return Transformer().parseexpr(buf)
>> File "/usr/lib/python2.5/compiler/transformer.py", line 133, in
>> parseexpr
>> return self.transform(parser.expr(text))
>> AttributeError: 'module' object has no attribute 'expr'
>>
>> If I understand the problem correctly, can anyone tell me where
>> python.expr() is defined, or suggest a better method to fix this
>> problem?
>>
>> Thanks,
>> Jeremiah
>>
>>
>
> Generic answers, I have no experience with pymol
>
> If pymol really needs that parser.py, you have a problem, as there can only
> be one module by that name in the application. But assuming it's needed for
> some obscure feature that you don't need, you could try the following
> sequence.
>
> 1) temporarily rename the pymol's parser.py file to something else, like
> pymolparser.py, and see what runs.
> 2) rather than changing the PYTHONPATH, fix up sys.path during your script
> initialization.
> In particular, do an import parser near the beginning of the script.
> This gets it loaded, even though you might not need to use it from this
> module.
> After that import, then add the following line (which could be generalized
> later)
> sys.path.append( "/usr/lib/pymodules/python2.5/pymol")
>
>
> If this works, then you can experiment a bit more, perhaps you don't need
> the extra import parser, just putting the pymol directory at the end of the
> sys.path rather than the beginning may be good enough.
>
> If the parser.py in the pymol is actually needed, you might need to rename
> its internal references to some other name, like pymolparser.
>
> HTH,
> DaveA
>
>
Thank you. Your second suggestion really helped.
To use pymol and numpy together, I now do the following:
To ~/.bashrc add:
PYMOL_PATH=/usr/lib/pymodules/python2.5/pymol
export PYMOL_PATH
Then I can do the following in python:
import numpy
numpy.save('123',numpy.array([1,2,3]))
numpy.load('123.npy')
array([1, 2, 3])
import sys
sys.path.append( "/usr/lib/pymodules/python2.5/pymol")
import pymol
pymol.finish_launching()
pymol.importing.load("/path/to/file.pdb")
Thanks,
Jeremiah
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Re: Linux, Python 2.5.2, serverless binding LDAP?
On Nov 12, 8:01 pm, alex23 wrote: > On Nov 13, 10:47 am, Kevin Cole wrote: > > > > > Hi, > > > I recently asked our IT department how to gain access to an > > addressbook. After carefully explaining that I was on a Linux system > > using Python, I got the reply: > > > "You should use our LDAP. With LDAP you can pull any data you want > > from Active Directory. On our network, the serverless binding address > > for our LDAP is ldap://dc=...,dc=...,dc=...,dc=..."; > > > with the actual "..." filled in. > > > I don't know squat about LDAP, but installed the python-ldap deb, and > > started glancing at the documentation on-line. I didn't see anything > > obvious for working with the URI above. Can I work w/ it? If so, a > > short example, please? > > > Thanx. > > http://www.python-ldap.org/doc/html/ldapurl.html#example Ah, it wasn't clear to me that "localhost:1389" meant serverless. Armed with that, I'm off to experiment. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Linux, Python 2.5.2, serverless binding LDAP?
On Nov 13, 10:47 am, Kevin Cole wrote: > Hi, > > I recently asked our IT department how to gain access to an > addressbook. After carefully explaining that I was on a Linux system > using Python, I got the reply: > > "You should use our LDAP. With LDAP you can pull any data you want > from Active Directory. On our network, the serverless binding address > for our LDAP is ldap://dc=...,dc=...,dc=...,dc=..."; > > with the actual "..." filled in. > > I don't know squat about LDAP, but installed the python-ldap deb, and > started glancing at the documentation on-line. I didn't see anything > obvious for working with the URI above. Can I work w/ it? If so, a > short example, please? > > Thanx. http://www.python-ldap.org/doc/html/ldapurl.html#example -- http://mail.python.org/mailman/listinfo/python-list
Linux, Python 2.5.2, serverless binding LDAP?
Hi, I recently asked our IT department how to gain access to an addressbook. After carefully explaining that I was on a Linux system using Python, I got the reply: "You should use our LDAP. With LDAP you can pull any data you want from Active Directory. On our network, the serverless binding address for our LDAP is ldap://dc=...,dc=...,dc=...,dc=..."; with the actual "..." filled in. I don't know squat about LDAP, but installed the python-ldap deb, and started glancing at the documentation on-line. I didn't see anything obvious for working with the URI above. Can I work w/ it? If so, a short example, please? Thanx. -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
On Nov 12, 2:37 pm, Bruno Desthuilliers wrote: > > Oh i get it now! If i assign a valid value to a variable the variable > > is also valid...thats...thats... GENUIS! *sarcasm* > > It's not about "assigning a valid value to a variable", it's about the > name being created (or not) in the current namespace, whatever it's > bound to. And thats what my sarcasm was alluding to. Steven's argument is moot because it will blow up either way due to the fact that "value" is non- existent! Every argument that has been brought forth about how this will break is just False and basically a bunch of FUD! It just garbage so you can discredit the idea. It's actually quite funny when someone as small as me can bring down the iron curtain of c.l.py. '''Mr. Gorbachev, Tear down this wall!''' How about one of you "esteemed" Pythonista's show me a real example where it will break. Show me (and the world) this H.G Wells nightmarish scenario you speak of but show no solid proofs. Sorry chaps, I don't buy snake oil! Going, Going, Goe, out the park! PS: And if it were so dangerous why would someone as knowledgeable as Carl have stepped in and supported it. I think because (like me) Carl put's the language before sewing circles. I think it's just personal like all the times before, that's OK, i have very thick skin! If it's wrong for a good reason i will graciously accept that, but no one has proven it's non-worth, not yet! -- http://mail.python.org/mailman/listinfo/python-list
Re: open source linux -> windows database connectivity?
Tony Schmidt wrote: > I am trying to read a Pervasive database on a Windows machine from a > Python script on a Linux machine. > > I understand that this can be done with a proprietary ODBC-to-ODBC > bridge called mxODBC or Easysoft OOB. The product is called "mxODBC Connect" and allows connecting from Python (running on pretty much any major platform) to a Windows or Linux server running the database: http://www.egenix.com/products/python/mxODBCConnect/ Note: The client part of this product is free. You only need to get a license for the server part. Alternatively, you can also our mxODBC single-tier product with the Pervasive ODBC driver available for Linux: http://ww1.pervasive.com/developerzone/platforms/linux.asp Regards, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Nov 12 2009) >>> Python/Zope Consulting and Support ...http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ ::: Try our new mxODBC.Connect Python Database Interface for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python with echo
Diez B. Roggisch wrote:
> with open("/sys/class/net/wlan1/device/tx_power", "w") as f:
> f.write("%i" % POWER)
IIRC the sys and proc virtual file system requires new line at the end
of a modifier. At least echo appends \n unless it's told otherwise.
Christian
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Re: 3.x and 2.x on same machine (is this info at Python.org??)
On Nov 12, 2:51 pm, Terry Reedy wrote: > rantingrick wrote: > > Hello, > > > Currently i am using 2.6 on Windows and need to start writing code in > > 3.0. I cannot leave 2.x yet because 3rd party modules are still not > > converted. So i want to install 3.0 without disturbing my current > > Python2.x. What i'm afraid of is that some SYSVARIABLE will get > > changed to Python3.0 and when i double click a Python script it will > > try and run Python 3.x instead of 2.x. I only want to run 3.0 scripts > > from the command line... > python3.x myscript.py > > > So how do i do this? Is my fear unfounded? > > When you install 3.1 (not 3.0), it asks whether to make 'this' the > default Python. Make sure the box is unchecked. Thanks for both of your replies, just to be safe though i'm going to back up everything ... Python 3000, here i come and i hope your ready for me!?!? Later Guy's! -- http://mail.python.org/mailman/listinfo/python-list
ANN: ActivePython 2.6.4.8 is now available
I'm happy to announce that ActivePython 2.6.4.8 is now available for download from: http://www.activestate.com/activepython/ This is a patch release that updates ActivePython to core Python 2.6.4. We recommend that you try 2.6 version first. See the release notes for full details: http://docs.activestate.com/activepython/2.6/relnotes.html#changes What is ActivePython? - ActivePython is ActiveState's binary distribution of Python. Builds for Windows, Mac OS X, Linux, HP-UX and AIX are made freely available. ActivePython includes the Python core and the many core extensions: zlib and bzip2 for data compression, the Berkeley DB (bsddb) and SQLite (sqlite3) database libraries, OpenSSL bindings for HTTPS support, the Tix GUI widgets for Tkinter, ElementTree for XML processing, ctypes (on supported platforms) for low-level library access, and others. The Windows distribution ships with PyWin32 -- a suite of Windows tools developed by Mark Hammond, including bindings to the Win32 API and Windows COM. Beginning the 2.6.3.7 release, ActivePython includes a binary package manager for Python (PyPM) that can be used to install packages much easily. See this page for full details: http://docs.activestate.com/activepython/2.6/whatsincluded.html As well, ActivePython ships with a wealth of documentation for both new and experienced Python programmers. In addition to the core Python docs, ActivePython includes the "What's New in Python" series, "Dive into Python", the Python FAQs & HOWTOs, and the Python Enhancement Proposals (PEPs). An online version of the docs can be found here: http://docs.activestate.com/activepython/2.6/ We would welcome any and all feedback to: activepython-feedb...@activestate.com Please file bugs against ActivePython at: http://bugs.activestate.com/query.cgi?set_product=ActivePython On what platforms does ActivePython run? ActivePython includes installers for the following platforms: - Windows/x86 - Windows/x64 (aka "AMD64") - Mac OS X - Linux/x86 - Linux/x86_64 (aka "AMD64") - Solaris/SPARC - Solaris/x86 - HP-UX/PA-RISC - AIX/PowerPC - AIX/PowerPC 64-bit Extra Bits -- ActivePython releases also include the following: - ActivePython26.chm: An MS compiled help collection of the full ActivePython documentation set. Linux users of applications such as xCHM might find this useful. This package is installed by default on Windows. Extra bits are available from: http://downloads.activestate.com/ActivePython/etc/ Thanks, and enjoy! The Python Team -- Sridhar Ratnakumar sridharr at activestate.com -- http://mail.python.org/mailman/listinfo/python-list
open source linux -> windows database connectivity?
I am trying to read a Pervasive database on a Windows machine from a Python script on a Linux machine. I understand that this can be done with a proprietary ODBC-to-ODBC bridge called mxODBC or Easysoft OOB. Is there anyway to do this with existing free/ open source tools? Thanks in advance for any tips. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python & Go
On 2009-11-12, Patrick Sabin wrote: > kj wrote: >> >> I'm just learning about Google's latest: the GO (Go?) language. >> (e.g. http://golang.org or http://www.youtube.com/watch?v=rKnDgT73v8s). >> There are some distinctly Pythonoid features to the syntax, such >> as "import this_or_that", the absence of parentheses at the top of >> flow control constructs, and quite a few statements without a >> trailing semicolon. Then again, there's a lot that looks distinctly >> un-Pythonlike, such as the curly brackets all over the place. And >> among the un-Pythonlike stuff there's a lot that looks like nothing >> else that I've ever seen... > > I don't see many similarities with python, Same here. Go syntax is much more like C/Java than Python. Sematically, I don't see much that's similar either. Go is statically typed. Go has no inheritence. Go has no exceptions ( no practical error handling AFAICT). Despite all the people who keep saying it's similar to Python, I don't really see what they're talking about. It seems more like C with garbage collection and interfaces, or maybe cleaned-up Java. -- Grant Edwards grante Yow! I have a VISION! It's at a RANCID double-FISHWICH on visi.coman ENRICHED BUN!! -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
r a écrit : > On Nov 11, 2:37 am, Steven D'Aprano > wrote: >> On Wed, 11 Nov 2009 00:08:58 -0800, r wrote: > >>> Yea it's called a NameError. Would it not also blow up in the current >>> state of syntax usage? >> No. >> >>> if var: >>> print 'var' >>> Traceback (most recent call last): >>> File "", line 1, in >>> if var: >>> NameError: name 'var' is not defined >> You missed a line: >> >> var = range(N) >> if var: > > Oh i get it now! If i assign a valid value to a variable the variable > is also valid...thats...thats... GENUIS! *sarcasm* It's not about "assigning a valid value to a variable", it's about the name being created (or not) in the current namespace, whatever it's bound to. -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
Steven D'Aprano a écrit : (snip) > Hint to would-be language designers: if you start off by claiming that a > new feature will save an indent level, when in fact it *doesn't* save an > indent level, you can save yourself from embarrassment by pressing Close > on your post instead of Send. Mou !-) Thanks Steven, you made my day (me ---> go back mouaa) -- http://mail.python.org/mailman/listinfo/python-list
JSR223 Access Python class instances through Java
I am trying to access (from Java) a python class that extends a Java interface. The following program runs fine in the jython console (I can instantiate Tada, call t.getName() and everything prints correctly.) However, if I invoke test1() from Java using JSR223, the returned object is inaccessible (proxy type) and none of the "in init", "in getName" strings will print. Furthermore, none of the lines print unless I convert ITest to a concrete class, but then the getName methods return the concrete implementation's string. Has anyone successfully had this situation work, and how did you do it? Thanks in advance Code: === import ITest class Tada(ITest): def __init__(self): print "In Init" def getName(self): print "In getName" return "Joe Schmoe" def test1(): t = Tada() print t.getName() print "Hello, World" return t -- http://mail.python.org/mailman/listinfo/python-list
Re: New syntax for blocks
r a écrit : -snip) > Just thinking out loud here...what if variable assignments could > return a value... hmmm? Not to them selfs of course but to a caller, > like an if statement... > > if a=openfile: > # do something with a Congratulations, you just reinvented one of the most infamous source of bugs in C, C++, Java, PHP, javascript and quite a few other languages. Believe it or not, but not allowing this in Python was a very deliberate design choice. Now whether it was a good choice is another troll^Mtopic !-) -- http://mail.python.org/mailman/listinfo/python-list
Re: python with echo
Steven D'Aprano wrote:
On Wed, 11 Nov 2009 17:24:37 -0800, hong zhang wrote:
List,
I have a question of python using echo.
POWER = 14
return_value = os.system('echo 14 >
/sys/class/net/wlan1/device/tx_power')
can assign 14 to tx_power
But
return_value = os.system('echo $POWER >
/sys/class/net/wlan1/device/tx_power')
POWER = 14 doesn't create an environment variable visible to echo. It is
a Python variable.
POWER = 14
import os
return_value = os.system('echo $POWER')
return_value
0
You can set environment variables from within Python using os.putenv:
>>> import os
>>> os.putenv('POWER', '14')
>>> return_value = os.system('echo $POWER')
14
>>> return_value
0
Keep in mind that putenv() only affects processes started by Python
after you call putenv. It does not, for example, affect the shell
process you used to invoke Python:
$ POWER=14
$ python -c 'import os
os.putenv("POWER", "42")
os.system("echo $POWER")'
42
$ echo $POWER
14
$
return_value is 256 not 0. It cannot assign 14 to tx_power.
I don't understand that. Exit status codes on all systems I'm familiar
with are limited to 0 through 255. What operating system are you using?
Probably some form of Unix. The value returned by os.system() is the
exit status shifted left one byte, for example:
>>> os.system("exit 1")
256
Hope this helps,
-- HansM
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Re: Python & Go
kj wrote: I'm just learning about Google's latest: the GO (Go?) language. (e.g. http://golang.org or http://www.youtube.com/watch?v=rKnDgT73v8s). There are some distinctly Pythonoid features to the syntax, such as "import this_or_that", the absence of parentheses at the top of flow control constructs, and quite a few statements without a trailing semicolon. Then again, there's a lot that looks distinctly un-Pythonlike, such as the curly brackets all over the place. And among the un-Pythonlike stuff there's a lot that looks like nothing else that I've ever seen... I don't see many similarities with python, especially it's syntax looks completely different to me. Google Go introduces many new concepts. Interfaces work a little bit like duck typing. You may call that python-style. And it has go-routines, which are a bit similar to generators (although I haven't look at them in detail). There is no exception handling, but channels should be able to substitute them, although I haven't checked that. At a first look it seems, that using Google Go effectively, someone has to relinquish many programming habits and adapt lots of new ones. - Patrick -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 12:44:00 -0800, Benjamin Kaplan wrote: Some one could even write an interpreter for C++ if they wanted to. Someone has (http://root.cern.ch/drupal/content/cint)! -- Rami Chowdhury "Never attribute to malice that which can be attributed to stupidity" -- Hanlon's Razor 408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD) -- http://mail.python.org/mailman/listinfo/python-list
Re: (OT) Recommend FTP Client
On 11/12/2009 11:26 AM, Dave Angel wrote: > Try http://fireftp.mozdev.org/ in the past i found this to be buggy. i'd recommend something different. what is your OS? -- david -- http://mail.python.org/mailman/listinfo/python-list
Re: Python & Go
Carl Banks wrote: Well, it's hard to argue with not being like C++, but the lack of inheritance is a doozie. Well it has the concept of embedding, which seems to be similar to inheritance. - Patrick -- http://mail.python.org/mailman/listinfo/python-list
Re: Computing the 1000th prime
Ray Holt wrote: I have an assigment to find the 1000th. prime using python. What's wrong with the following code: PrimeCount = 0 PrimeCandidate = 1 while PrimeCount < 2000: IsPrime = True PrimeCandidate = PrimeCandidate + 2 for x in range(2, PrimeCandidate): if PrimeCandidate % x == 0: ##print PrimeCandidate, 'equals', x, '*', PrimeCandidate/x print PrimeCandidate IsPrime = False break if IsPrime: PrimeCount = PrimeCount + 1 PrimeCandidate = PrimeCandidate + 2 print PrimeCandidate Thanks There are a bunch of things wrong here. Did you write this code, or was it copied from somewhere else? Because it looks like there are several typos, that you could catch by inspection. First, at what point in the loop do you decide that you have a prime? Why not add a print there, printing the prime, instead of printing a value that's already been incremented beyond it. And put labels on your prints, or you'll never be able to decipher the output. Chnage the limit for PrimeCount to something small while you're debugging, because you can figure out small primes and composites by hand. Second, you have a loop which divides by x. But you change the PrimeCandidate within the loop, so it's not dividing the same value each time through. Check your indentation. Third, your limit value is too high. You aren't looking for 2000 primes, but 1000 of them. Further, your count is off by 1, as this loop doesn't identify 2 as a prime. I'd recommend making this whole thing a function, and have it actually build and return a list of primes. Then the caller can check both the size of the list and do a double check of the primality of each member. And naturally you'll be able to more readily check it yourself, either by eye or by comparing it to one of the standard list of primes you can find on the internet. The function should take a count, and loop until the len(primelist) matches the count. Then just return the primelist. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: 3.x and 2.x on same machine (is this info at Python.org??)
rantingrick wrote: Hello, Currently i am using 2.6 on Windows and need to start writing code in 3.0. I cannot leave 2.x yet because 3rd party modules are still not converted. So i want to install 3.0 without disturbing my current Python2.x. What i'm afraid of is that some SYSVARIABLE will get changed to Python3.0 and when i double click a Python script it will try and run Python 3.x instead of 2.x. I only want to run 3.0 scripts from the command line... > python3.x myscript.py So how do i do this? Is my fear unfounded? When you install 3.1 (not 3.0), it asks whether to make 'this' the default Python. Make sure the box is unchecked. -- http://mail.python.org/mailman/listinfo/python-list
Re: 3.x and 2.x on same machine (is this info at Python.org??)
On Thu, Nov 12, 2009 at 2:52 PM, rantingrick wrote: > Hello, > > Currently i am using 2.6 on Windows and need to start writing code in > 3.0. I cannot leave 2.x yet because 3rd party modules are still not > converted. So i want to install 3.0 without disturbing my current > Python2.x. What i'm afraid of is that some SYSVARIABLE will get > changed to Python3.0 and when i double click a Python script it will > try and run Python 3.x instead of 2.x. I only want to run 3.0 scripts > from the command line... > python3.x myscript.py > > So how do i do this? Is my fear unfounded? > At least on *nix (including OS X), installing Python 3 does exactly what you want by default. I don't know how it handles it on Windows. > Thanks > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, Nov 12, 2009 at 2:24 PM, Alf P. Steinbach wrote: > > You'll also find it impossible to rigorously define "dynamic language" in a > general way so that that definition excludes C++. > > So, to anyone who understands what one is talking about, "interpreted", or > e.g. "slow language" (as was the case here), conveys the essence. > > And to anyone who doesn't understand it trying to be more precise is an > exercise in futility and pure silliness -- except for the purpose of > misleading. You just made Rami's point. You can't define a language as . You can however describe what features it has - static vs. dynamic typing, duck-typing, dynamic dispatch, and so on. Those are features of the language. Other things, like "interpreted" vs "compiled" are features of the implementation. C++ for instance is considered language that gets compiled to machine code. However, Visual Studio can compile C++ programs to run on the .NET framework which makes them JIT compiled. Some one could even write an interpreter for C++ if they wanted to. -- http://mail.python.org/mailman/listinfo/python-list
Re: Psyco on 64-bit machines
On Thu, Nov 12, 2009 at 12:06 PM, Russ P. wrote: > I have a Python program that runs too slow for some inputs. I would > like to speed it up without rewriting any code. Psyco seemed like > exactly what I need, until I saw that it only works on a 32-bit > architecture. I work in an environment of Sun Ultras that are all 64- > bit. However, the Psyco docs say this: > > "Psyco does not support the 64-bit x86 architecture, unless you have a > Python compiled in 32-bit compatibility mode." > > Would it make sense to compile Python in the 32-bit compatibility mode > so I can use Psyco? What would I lose in that mode, if anything? > Thanks. > -- > http://mail.python.org/mailman/listinfo/python-list > The only things you should lose by using a 32-bit version of Python is access to the memory beyond the 4GB limit (approximate - the OS takes some of that), and any compiled extension modules you cannot find or recompile for 32-bit (.pyd on Windows - I think .so on Linux). Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 12:02:11 -0800, Alf P. Steinbach wrote: I think that was in the part you *snipped* here. Just fill in the mentioned qualifications and weasel words. OK, sure. I don't think they're weasel words, because I find them useful, but I think I see where you're coming from. Specifically, I reacted to the statement that>, made in response to someone upthread, in the context of Google finding CPython overall too slow. IIRC it was "the speed of a language" that was asserted to be nonsense, wasn't it? Which IMO is fair -- a physicist friend of mine works with a C++ interpreter which is relatively sluggish, but that doesn't mean C++ is slow... -- Rami Chowdhury "Never attribute to malice that which can be attributed to stupidity" -- Hanlon's Razor 408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD) -- http://mail.python.org/mailman/listinfo/python-list
Re: Computing the 1000th prime
On Thursday, November 12, 2009, Benjamin Kaplan wrote: > On Thursday, November 12, 2009, Ray Holt wrote: >> >> >> >> >> >> I have an assigment >> to find the 1000th. prime using python. What's wrong with the following >> code: >> PrimeCount = >> 0 >> PrimeCandidate = 1 >> while PrimeCount < 2000: >> >> IsPrime = True >> PrimeCandidate = PrimeCandidate + >> 2 >> for x in range(2, >> PrimeCandidate): >> if PrimeCandidate >> % x == >> 0: >> ## print >> PrimeCandidate, 'equals', x, '*', >> PrimeCandidate/x >> >> print PrimeCandidate >> >> >> IsPrime = >> False >> >> break >> if >> IsPrime: > > You break on the first composite number, which means you immediately > exit the loop. Just let it fall through Also, a couple of things to > speed in up: > Nevermind MRAB is right. I missed the indentation error there. I guess that's what I get for trying to evaluate code on my iPod touch instead of getting my computer out and actually seeing what it's doing. >.< > 1) you look at all numbers from 2 to n to check if n is a prime > number. You only need to check from 2 to int(math.sqrt(n)) > > 2) to really speed it up, keep a list of all the prime numbers. Then > you only need to check if a number is divisible by those > > By combining the two, you'll only use a fraction of the comparisons. > For 23, you'd only loop twice (2 and 3) instead of 20 times to > determine that it's prime. The difference is even more dramatic on > large numbers. > -- http://mail.python.org/mailman/listinfo/python-list
Psyco on 64-bit machines
I have a Python program that runs too slow for some inputs. I would like to speed it up without rewriting any code. Psyco seemed like exactly what I need, until I saw that it only works on a 32-bit architecture. I work in an environment of Sun Ultras that are all 64- bit. However, the Psyco docs say this: "Psyco does not support the 64-bit x86 architecture, unless you have a Python compiled in 32-bit compatibility mode." Would it make sense to compile Python in the 32-bit compatibility mode so I can use Psyco? What would I lose in that mode, if anything? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Computing the 1000th prime
On Thursday, November 12, 2009, Ray Holt wrote: > > > > > > I have an assigment > to find the 1000th. prime using python. What's wrong with the following > code: > PrimeCount = > 0 > PrimeCandidate = 1 > while PrimeCount < 2000: > > IsPrime = True > PrimeCandidate = PrimeCandidate + > 2 > for x in range(2, > PrimeCandidate): > if PrimeCandidate > % x == > 0: > ## print > PrimeCandidate, 'equals', x, '*', > PrimeCandidate/x > > print PrimeCandidate > > > IsPrime = > False > > break > if > IsPrime: > > PrimeCount = PrimeCount + > 1 > > PrimeCandidate = PrimeCandidate + > 2 > print > PrimeCandidate > Thanks > You break on the first composite number, which means you immediately exit the loop. Just let it fall through Also, a couple of things to speed in up: 1) you look at all numbers from 2 to n to check if n is a prime number. You only need to check from 2 to int(math.sqrt(n)) 2) to really speed it up, keep a list of all the prime numbers. Then you only need to check if a number is divisible by those By combining the two, you'll only use a fraction of the comparisons. For 23, you'd only loop twice (2 and 3) instead of 20 times to determine that it's prime. The difference is even more dramatic on large numbers. -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
* Rami Chowdhury: On Thu, 12 Nov 2009 11:24:18 -0800, Alf P. Steinbach wrote: * Rami Chowdhury: On Thu, 12 Nov 2009 09:32:28 -0800, Alf P. Steinbach wrote: This also seems religious. It's like in Norway it became illegal to market lemon soda, since umpteen years ago it's soda with lemon flavoring. This has to do with the *origin* of the citric acid, whether natural or chemist's concoction, no matter that it's the same chemical. So, some people think that it's wrong to talk about interpreted languages, hey, it should be a "language designed for interpretation", or better yet, "dynamic language", or bestest, "language with dynamic flavor". And slow language, oh no, should be "language whose current implementations are perceived as somewhat slow by some (well, all) people", but of course, that's just silly. Perhaps I'm missing the point of what you're saying but I don't see why you're conflating interpreted and dynamic here? Javascript is unarguably a dynamic language, yet Chrome / Safari 4 / Firefox 3.5 all typically JIT it. Does that make Javascript non-dynamic, because it's compiled? What about Common Lisp, which is a compiled language when it's run with CMUCL or SBCL? Yeah, you missed it. Blurring and coloring and downright hiding reality by insisting on misleading but apparently more precise terminology for some vague concept is a popular sport, and chiding others for using more practical and real-world oriented terms, can be effective in politics and some other arenas. But in a technical context it's silly. Or dumb. Whatever. E.g. you'll find it impossible to define interpretation rigorously in the sense that you're apparently thinking of. Well, sure. Can you explain, then, what sense you meant it in? I think that was in the part you *snipped* here. Just fill in the mentioned qualifications and weasel words. And considering that a routine might be an intepreter of data produced elsewhere in program, needs some fixing... You'll also find it impossible to rigorously define "dynamic language" in a general way so that that definition excludes C++. Or, for that matter, suitably clever assembler. I'm not arguing with you there. So, to anyone who understands what one is talking about, "interpreted", or e.g. "slow language" (as was the case here), conveys the essence. Not when the context isn't clear, it doesn't. And to anyone who doesn't understand it trying to be more precise is an exercise in futility and pure silliness -- except for the purpose of misleading. Or for the purpose of greater understanding, surely - and isn't that the point? I don't think that was the point. Specifically, I reacted to the statement that>, made in response to someone upthread, in the context of Google finding CPython overall too slow. It is quite slow. ;-) Cheers, - Alf -- http://mail.python.org/mailman/listinfo/python-list
3.x and 2.x on same machine (is this info at Python.org??)
Hello, Currently i am using 2.6 on Windows and need to start writing code in 3.0. I cannot leave 2.x yet because 3rd party modules are still not converted. So i want to install 3.0 without disturbing my current Python2.x. What i'm afraid of is that some SYSVARIABLE will get changed to Python3.0 and when i double click a Python script it will try and run Python 3.x instead of 2.x. I only want to run 3.0 scripts from the command line... > python3.x myscript.py So how do i do this? Is my fear unfounded? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: (OT) Recommend FTP Client
Thanks. V On Thu, Nov 12, 2009 at 2:26 PM, Dave Angel wrote: > > > Victor Subervi wrote: > >> Hi; >> Someone on this list just recommended I find an ftp client that enables me >> to change line endings. He indicated that it would be easy, but googling I >> haven't been able to find one. I would prefer a free client, but whatever. >> Please send me a recommendation. >> TIA, >> Victor >> >> >> > Try http://fireftp.mozdev.org/ > > fireftp is an (free) addon to Firefox. If you're already using Firefox, > it's painless to download it, and easy to use. You can set up account(s) > complete with passwords and default directories, and then transfer > individual files or directory trees full just by selecting and pressing the > Arrow icons (one for upload, one for download). You can sort by timestamp, > so it's not hard to just transfer new stuff. > > > One of the Tools->Options tabs is "Downloads/Uploads". First box looks > like: > > When transferring files use: > o - Automatic mode > o - Binary mode > o - ASCII mode > > > According to the help, Automatic mode is very useful for CGI scripts, where > you specify which extensions will get the line-endings converted. > http://fireftp.mozdev.org/help.html > > But please understand: I personally use Binary mode in FireFTP because I'm > a control freak. Python can handle Unix line-endings just fine, so any > files that are bound for CGI I just edit in that mode in the first place. > > > DaveA > > -- http://mail.python.org/mailman/listinfo/python-list
Re: Computing the 1000th prime
Ray Holt wrote: I have an assigment to find the 1000th. prime using python. What's wrong with the following code: PrimeCount = 0 PrimeCandidate = 1 while PrimeCount < 2000: IsPrime = True PrimeCandidate = PrimeCandidate + 2 for x in range(2, PrimeCandidate): if PrimeCandidate % x == 0: ##print PrimeCandidate, 'equals', x, '*', PrimeCandidate/x print PrimeCandidate IsPrime = False break if IsPrime: PrimeCount = PrimeCount + 1 PrimeCandidate = PrimeCandidate + 2 print PrimeCandidate Thanks The indentation starting from the second 'if'. -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 11:24:18 -0800, Alf P. Steinbach wrote: * Rami Chowdhury: On Thu, 12 Nov 2009 09:32:28 -0800, Alf P. Steinbach wrote: This also seems religious. It's like in Norway it became illegal to market lemon soda, since umpteen years ago it's soda with lemon flavoring. This has to do with the *origin* of the citric acid, whether natural or chemist's concoction, no matter that it's the same chemical. So, some people think that it's wrong to talk about interpreted languages, hey, it should be a "language designed for interpretation", or better yet, "dynamic language", or bestest, "language with dynamic flavor". And slow language, oh no, should be "language whose current implementations are perceived as somewhat slow by some (well, all) people", but of course, that's just silly. Perhaps I'm missing the point of what you're saying but I don't see why you're conflating interpreted and dynamic here? Javascript is unarguably a dynamic language, yet Chrome / Safari 4 / Firefox 3.5 all typically JIT it. Does that make Javascript non-dynamic, because it's compiled? What about Common Lisp, which is a compiled language when it's run with CMUCL or SBCL? Yeah, you missed it. Blurring and coloring and downright hiding reality by insisting on misleading but apparently more precise terminology for some vague concept is a popular sport, and chiding others for using more practical and real-world oriented terms, can be effective in politics and some other arenas. But in a technical context it's silly. Or dumb. Whatever. E.g. you'll find it impossible to define interpretation rigorously in the sense that you're apparently thinking of. Well, sure. Can you explain, then, what sense you meant it in? You'll also find it impossible to rigorously define "dynamic language" in a general way so that that definition excludes C++. Or, for that matter, suitably clever assembler. I'm not arguing with you there. So, to anyone who understands what one is talking about, "interpreted", or e.g. "slow language" (as was the case here), conveys the essence. Not when the context isn't clear, it doesn't. And to anyone who doesn't understand it trying to be more precise is an exercise in futility and pure silliness -- except for the purpose of misleading. Or for the purpose of greater understanding, surely - and isn't that the point? -- Rami Chowdhury "Never attribute to malice that which can be attributed to stupidity" -- Hanlon's Razor 408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD) -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
On Nov 12, 11:31 am, Terry Reedy wrote: > Alf P. Steinbach wrote: > > One reaction to >http://preview.tinyurl.com/ProgrammingBookP3> has been that turtle > > graphics may be off-putting to some readers because it is associated > > with children's learning. > > > What do you think? > > I just started using the module for simple plots. > I am not a child. > You cannot please everyone. I used Turtle back on the Apple in the early 80's... so I personally have very positive feelings towards it ;) To each their own eh? -- http://mail.python.org/mailman/listinfo/python-list
Re: Does turtle graphics have the wrong associations?
Alf P. Steinbach wrote: One reaction to http://preview.tinyurl.com/ProgrammingBookP3> has been that turtle graphics may be off-putting to some readers because it is associated with children's learning. What do you think? I just started using the module for simple plots. I am not a child. You cannot please everyone. -- http://mail.python.org/mailman/listinfo/python-list
Re: python with echo
Steven D'Aprano wrote:
On Wed, 11 Nov 2009 17:24:37 -0800, hong zhang wrote:
List,
I have a question of python using echo.
POWER = 14
return_value = os.system('echo 14 >
/sys/class/net/wlan1/device/tx_power')
can assign 14 to tx_power
But
return_value = os.system('echo $POWER >
/sys/class/net/wlan1/device/tx_power')
POWER = 14 doesn't create an environment variable visible to echo. It is
a Python variable.
POWER = 14
import os
return_value = os.system('echo $POWER')
return_value
0
return_value is 256 not 0. It cannot assign 14 to tx_power.
I don't understand that. Exit status codes on all systems I'm familiar
with are limited to 0 through 255. What operating system are you using?
Assuming your system allows two-byte exit statuses, you should check the
documentation for echo and the shell to see why it is returning 256.
In some OSs the exit status consists of 2 fields, one being the child
process's exit status and the other being supplied by the OS.
The reason is simple. What if the child process terminated abnormally?
You'd like an exit status to tell you that, but you wouldn't want it to
be confused with the child process's own exit status, assuming that it
had terminated normally.
Have you tried this in the shell, without involving Python? I will almost
guarantee that Python is irrelevant to the problem.
--
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Re: (OT) Recommend FTP Client
Victor Subervi wrote: Hi; Someone on this list just recommended I find an ftp client that enables me to change line endings. He indicated that it would be easy, but googling I haven't been able to find one. I would prefer a free client, but whatever. Please send me a recommendation. TIA, Victor Try http://fireftp.mozdev.org/ fireftp is an (free) addon to Firefox. If you're already using Firefox, it's painless to download it, and easy to use. You can set up account(s) complete with passwords and default directories, and then transfer individual files or directory trees full just by selecting and pressing the Arrow icons (one for upload, one for download). You can sort by timestamp, so it's not hard to just transfer new stuff. One of the Tools->Options tabs is "Downloads/Uploads". First box looks like: When transferring files use: o - Automatic mode o - Binary mode o - ASCII mode According to the help, Automatic mode is very useful for CGI scripts, where you specify which extensions will get the line-endings converted. http://fireftp.mozdev.org/help.html But please understand: I personally use Binary mode in FireFTP because I'm a control freak. Python can handle Unix line-endings just fine, so any files that are bound for CGI I just edit in that mode in the first place. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
* Rami Chowdhury: On Thu, 12 Nov 2009 09:32:28 -0800, Alf P. Steinbach wrote: This also seems religious. It's like in Norway it became illegal to market lemon soda, since umpteen years ago it's soda with lemon flavoring. This has to do with the *origin* of the citric acid, whether natural or chemist's concoction, no matter that it's the same chemical. So, some people think that it's wrong to talk about interpreted languages, hey, it should be a "language designed for interpretation", or better yet, "dynamic language", or bestest, "language with dynamic flavor". And slow language, oh no, should be "language whose current implementations are perceived as somewhat slow by some (well, all) people", but of course, that's just silly. Perhaps I'm missing the point of what you're saying but I don't see why you're conflating interpreted and dynamic here? Javascript is unarguably a dynamic language, yet Chrome / Safari 4 / Firefox 3.5 all typically JIT it. Does that make Javascript non-dynamic, because it's compiled? What about Common Lisp, which is a compiled language when it's run with CMUCL or SBCL? Yeah, you missed it. Blurring and coloring and downright hiding reality by insisting on misleading but apparently more precise terminology for some vague concept is a popular sport, and chiding others for using more practical and real-world oriented terms, can be effective in politics and some other arenas. But in a technical context it's silly. Or dumb. Whatever. E.g. you'll find it impossible to define interpretation rigorously in the sense that you're apparently thinking of. It's not that kind of term or concept. The nearest you can get is in a different direction, something like "a program whose actions are determined by data external to the program (+ x qualifications and weasel words)", which works in-practice, conceptually, but try that on as a rigorous definition and you'll see that when you get formal about it then it's completely meaningless: either anything qualifies or nothing qualifies. You'll also find it impossible to rigorously define "dynamic language" in a general way so that that definition excludes C++. So, to anyone who understands what one is talking about, "interpreted", or e.g. "slow language" (as was the case here), conveys the essence. And to anyone who doesn't understand it trying to be more precise is an exercise in futility and pure silliness -- except for the purpose of misleading. Cheers & hth., - Alf -- http://mail.python.org/mailman/listinfo/python-list
Re: regex remove closest tag
S.Selvam wrote:
Hi all,
1) I need to remove the tags which is just before the keyword(i.e
some_text2 ) excluding others.
2) input string may or may not contain tags.
3) Sample input:
inputstr = """start some_text1 href="">some_text2 keyword anything"""
4) I came up with the following regex,
p=re.compile(r'(?P.*?)(\s*keyword|\s*keyword)(?P.*)',re.DOTALL|re.I)
s=p.search(inputstr)
but second group matches both tags,while i need to match the
recent one only.
I would like to get your suggestions.
Note:
If i leave group('good1') as greedy, then it matches both the tag.
".*?" can match any number of any character, so it can match any
intervening "" tags. Try "[^<]*?" instead.
--
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Computing the 1000th prime
I have an assigment to find the 1000th. prime using python. What's wrong with the following code: PrimeCount = 0 PrimeCandidate = 1 while PrimeCount < 2000: IsPrime = True PrimeCandidate = PrimeCandidate + 2 for x in range(2, PrimeCandidate): if PrimeCandidate % x == 0: ##print PrimeCandidate, 'equals', x, '*', PrimeCandidate/x print PrimeCandidate IsPrime = False break if IsPrime: PrimeCount = PrimeCount + 1 PrimeCandidate = PrimeCandidate + 2 print PrimeCandidate Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: QuerySets in Dictionaries
scoopseven schrieb:
I need to create a dictionary of querysets. I have code that looks
like:
query1 = Myobject.objects.filter(status=1)
query2 = Myobject.objects.filter(status=2)
query3 = Myobject.objects.filter(status=3)
d={}
d['a'] = query1
d['b'] = query2
d['c'] = query3
Is there a way to do this that I'm missing?
d = dict(a=Myobject.objects.filter(status=1),
b=Myobject.objects.filter(status=2),
c=Myobject.objects.filter(status=3))
Diez
--
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Re: QuerySets in Dictionaries
2009/11/12 scoopseven :
> I need to create a dictionary of querysets. I have code that looks
> like:
>
> query1 = Myobject.objects.filter(status=1)
> query2 = Myobject.objects.filter(status=2)
> query3 = Myobject.objects.filter(status=3)
>
> d={}
> d['a'] = query1
> d['b'] = query2
> d['c'] = query3
>
> Is there a way to do this that I'm missing?
Untested:
wanted = (('a', 1), ('b', 2), ('c', 2))
d = dict((key, Myobject.objects.filter(status=number)) for (key,
number) in wanted)
--
Cheers,
Simon B.
--
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Re: #define (from C) in Python
If it's such a big hairy deal, just recompile a copy of the C Pre Processor to use something other then #, and hook it up to your python scripts in a pipe line from a shell wrapper. Personally, I'd rather have Lisps lambda or perls sub then Cs preprocessor, and even in those cases, Python suffices perfectly fine ;). -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
On Thu, 12 Nov 2009 09:32:28 -0800, Alf P. Steinbach wrote: This also seems religious. It's like in Norway it became illegal to market lemon soda, since umpteen years ago it's soda with lemon flavoring. This has to do with the *origin* of the citric acid, whether natural or chemist's concoction, no matter that it's the same chemical. So, some people think that it's wrong to talk about interpreted languages, hey, it should be a "language designed for interpretation", or better yet, "dynamic language", or bestest, "language with dynamic flavor". And slow language, oh no, should be "language whose current implementations are perceived as somewhat slow by some (well, all) people", but of course, that's just silly. Perhaps I'm missing the point of what you're saying but I don't see why you're conflating interpreted and dynamic here? Javascript is unarguably a dynamic language, yet Chrome / Safari 4 / Firefox 3.5 all typically JIT it. Does that make Javascript non-dynamic, because it's compiled? What about Common Lisp, which is a compiled language when it's run with CMUCL or SBCL? -- Rami Chowdhury "Never attribute to malice that which can be attributed to stupidity" -- Hanlon's Razor 408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD) -- http://mail.python.org/mailman/listinfo/python-list
Re: (OT) Recommend FTP Client
Someone on this list just recommended I find an ftp client that enables me to change line endings. He indicated that it would be easy, but googling I haven't been able to find one. I would prefer a free client, but whatever. Please send me a recommendation. How about the command line client that comes with every modern OS? Just use the ASCII (default) and BIN commands to switch between line-ending translation. -tkc -- http://mail.python.org/mailman/listinfo/python-list
QuerySets in Dictionaries
I need to create a dictionary of querysets. I have code that looks
like:
query1 = Myobject.objects.filter(status=1)
query2 = Myobject.objects.filter(status=2)
query3 = Myobject.objects.filter(status=3)
d={}
d['a'] = query1
d['b'] = query2
d['c'] = query3
Is there a way to do this that I'm missing?
Thanks.
--
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Re: How can a module know the module that imported it?
On Nov 12, 10:10 am, Ethan Furman wrote:
> AK Eric wrote:
> > so:
>
> > # moduleA.py
> > import moduleB
>
> > # moduleB.py
> > import sys
> > stuff = sys._getframe(1).f_locals
> > print stuff
>
> > Prints:
>
> > {'__builtins__': ,
> > '__file__': 'C:\\Documents and SettingsMy Documents\
> > \python\\moduleA.py',
> > '__name__': '__main__',
> > '__doc__': None}
>
> > Looks like you could query stuff['__file__'] to pull what you're
> > after.
> > ?
>
> The leading _ in _getframe indicates a private function to sys (aka
> implementation detail); in other words, something that could easily
> change between one Python version and the next.
>
> I'm using the inspect module (for the moment, at least), and my question
> boils down to: Will it work correctly on all versions of Python in the
> 2.x range? 3.x range?
>
Good point, I totally missed that. Someone had passed that solution
to me at one point and I was so excited I kind of looked that over :P
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Re: How can a module know the module that imported it?
AK Eric wrote:
so:
# moduleA.py
import moduleB
# moduleB.py
import sys
stuff = sys._getframe(1).f_locals
print stuff
Prints:
{'__builtins__': ,
'__file__': 'C:\\Documents and SettingsMy Documents\
\python\\moduleA.py',
'__name__': '__main__',
'__doc__': None}
Looks like you could query stuff['__file__'] to pull what you're
after.
?
The leading _ in _getframe indicates a private function to sys (aka
implementation detail); in other words, something that could easily
change between one Python version and the next.
I'm using the inspect module (for the moment, at least), and my question
boils down to: Will it work correctly on all versions of Python in the
2.x range? 3.x range?
~Ethan~
--
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Re: standard libraries don't behave like standard 'libraries'
On Thu, Nov 12, 2009 at 12:05 PM, Sriram Srinivasan wrote: >> So all libraries written have to use the common subset, which - unless >> things are *removed*, which with python3 actually happened - is always >> the oldest interpreter. And if a feature goes away, they have to be >> rewritten with the then common subset. > > you see that's the problem with py3. instead of slowly removing the > features one by one till the end they made a jump. the problem is not > with the jump but with other libraries/packages that depend on py2. > what i felt was if the new version was available as soon as it is into > the stream, developers/users try to use them and get accustomed. now > they follow this. they have frozen py3 for may be 2-3 years so ppl > would move slowly to py2.6 ,2.7, 2.8... most. also the corporate > companies are the most influential. > The freeze was put in place so that the other implementations of Python, like Jython and IronPython, have a chance to catch up with the reference CPython implementation. It's not so people will slowly move up. FWIW, people knew for years what was going to change in Python 3. > also a point to note: if new updates keep on coming (for eg. daily > antivirus update) developers tend to accept and move on *easily*. > > i am not an expert in programming/interpreter design/library writing/ > packaging. i just wanted the standard library *too* to be pluggable, > not just the applications based on it. > i am not even experienced in python to make bold accusations so all i > can say is 'how it would be if?' and i always stick to one thing 'why > not?'. > >> In other words: as a library writer, I can't use shiny, new & better >> features, I'm stuck with the old stuff, and whenever the interpreter >> evolves I have to rewrite even the old ones. Not appealing. Why develop >> the interpreter at all then? > > if you are app developer you needn't rewrite anything. that is the > main point here! just specifying the interpreter and library version > is enough every thing has to work like magic. as the previous > library&interpreter wont be removed (unless and until it is your will) > u can use them. thats how everybody would like it to be. > So you're saying that we'd have multiple versions of the interpreter running at the same time, but they all have access to the same memory. That wouldn't just require a change to Python, that would require a change to the way all modern operating systems work. > as for a library writer is concerned: as you say it depends on certain > things like other libraries,interpreter,etc. but i would like to say > that change is inevitable. if some core developer has to change > something he might change. and if you have to update your library you > have to. this applies to the interpreter too. what python now does is > make every update work with the minimal set (giving minimal backward > compatibility) plus the new features too. which is exactly the right > thing. what i wanted is the users have to be aware now and then when > of the modification, deletion, addition stuff not in every release as > in py3k. then the whole backward incompatibility issue would be > *dissolved* or what i mean is *diffused* and ppl dont even know that > they have switched over to a very new thing. > > Actually, that's not entirely true. New versions to break things Consider these statements as = ['a','a','a'] with = [1,2,3] It's legal in Python 2.4 or earlier, a warning in Python 2.5, but illegal in Python 2.6 > >> In other words: the problem is solved by somehow solving the problem - >> but not by a concrete solution you propose? > > as i told before i neither know the problem nor the solution. i just > wrote my ideas/imagination down > >> PyPy is cool, but by far not advanced enough to replace external, >> C-based libraries such as NUMPY and PyQt and whatnot. >> >> I don't say that the current situation is by any means ideal. There is a >> lot to be said about package creation, distribution, installation, >> removal, dependency handling, and even system-packaging-integration if >> one likes. >> >> You IMHO just add another layer of complexity on top of it, without >> proposing solutions to any of the layers in between, nor your new one - >> namely, the interpreter version agnosticism. > > yes you are right. python has a lot of bindings to a lot of stuff. but > it is the strength and weakness. not exactly pythons weakness but with > the thing on the other side. yes it may be looking complex because > most of the 'standard library' system was not designed to be adhoc/add- > on/pluggable from the start. It is pluggable. The standard library consists of Python modules like any other. 2.6's multiprocessing module is just an incorporation of the pyprocessing module for instance. The point of the standard library is that you can count on it being there, and you can count on it having certain features, given your interpreter version. You can also be sure that anytime a new ver
Re: Writing an emulator in python - implementation questions (for performance)
Oops, numpy arrays start with index=0 :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: How can a module know the module that imported it?
so:
# moduleA.py
import moduleB
# moduleB.py
import sys
stuff = sys._getframe(1).f_locals
print stuff
Prints:
{'__builtins__': ,
'__file__': 'C:\\Documents and SettingsMy Documents\
\python\\moduleA.py',
'__name__': '__main__',
'__doc__': None}
Looks like you could query stuff['__file__'] to pull what you're
after.
?
--
http://mail.python.org/mailman/listinfo/python-list
Re: Writing an emulator in python - implementation questions (for performance)
> You can do clever memory slicing like this with numpy. For instance: > > breg = numpy.zeros((16,),numpy.uint8) > wreg = numpy.ndarray((8,),numpy.uint16,breg) > > This causes breg and wreg to share the same 16 bytes of memory. You > can define constants to access specific registers: What I'm doing wrong? [srom...@compiler:~]$ cat test.py #!/usr/bin/python import numpy # Register array breg = numpy.zeros((16,),numpy.uint8) wreg = numpy.ndarray((8,), numpy.uint16, breg ) reg_A = 1 reg_F = 2 reg_AF = 1 reg_B = 3 reg_C = 4 reg_BC = 3 breg[reg_B] = 5 breg[reg_C] = 10 print breg[reg_B] print breg[reg_C] print wreg[reg_BC] [srom...@compiler:~]$ python test.py 5 10 0 ? -- http://mail.python.org/mailman/listinfo/python-list
Re: #define (from C) in Python
Santiago Romero, 12.11.2009 18:23: > #define LD_r_n(reg) (reg) = Z80ReadMem(r_PC++) > > #define LD_rr_nn(reg) r_opl = Z80ReadMem(r_PC); r_PC++; \ > r_oph = Z80ReadMem(r_PC); r_PC++; \ > reg = r_op > > #define LOAD_r(dreg, saddreg) (dreg)=Z80ReadMem((saddreg)) > > #define LOAD_rr_nn(dreg) r_opl = Z80ReadMem(r_PC); r_PC++; \ >r_oph = Z80ReadMem(r_PC); r_PC++; \ >r_tmpl = Z80ReadMem(r_op); \ >r_tmph = Z80ReadMem((r_op)+1); \ >dreg=r_tmp > > #define STORE_nn_rr(dreg) \ > r_opl = Z80ReadMem(r_PC); r_PC++;\ > r_oph = Z80ReadMem(r_PC); r_PC++; \ > r_tmp = dreg; \ > Z80WriteMem((r_op),r_tmpl, regs); \ > Z80WriteMem((r_op+1),r_tmph, regs) > > But it seems that is not possible :-( As Michele said, this is a micro optimisation, likely premature. A function is usually good enough for this. If you need more speed (and you seem to be targeting direct memory access or something like that), take a look at Cython. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
mcherm writes: > On Nov 11, 7:38 pm, Vincent Manis wrote: >> 1. The statement `Python is slow' doesn't make any sense to me. >> Python is a programming language; it is implementations that have >> speed or lack thereof. >[...] >> 2. A skilled programmer could build an implementation that compiled >> Python code into Common Lisp or Scheme code, and then used a >> high-performance Common Lisp compiler... > > I think you have a fundamental misunderstanding of the reasons why > Python is > slow. Most of the slowness does NOT come from poor implementations: > the CPython > implementation is extremely well-optimized; the Jython and Iron Python > implementations use best-in-the-world JIT runtimes. Most of the speed > issues > come from fundamental features of the LANGUAGE itself, mostly ways in > which > it is highly dynamic. > > In Python, a piece of code like this: > len(x) > needs to watch out for the following: > * Perhaps x is a list OR > * Perhaps x is a dict OR > * Perhaps x is a user-defined type that declares a __len__ > method OR > * Perhaps a superclass of x declares __len__ OR > * Perhaps we are running the built-in len() function OR > * Perhaps there is a global variable 'len' which shadows the > built-in OR > * Perhaps there is a local variable 'len' which shadows the > built-in OR > * Perhaps someone has modified __builtins__ > > In Python it is possible for other code, outside your module to go in > and > modify or replace some methods from your module (a feature called > "monkey-patching" which is SOMETIMES useful for certain kinds of > testing). > There are just so many things that can be dynamic (even if 99% of the > time > they are NOT dynamic) that there is very little that the compiler can > assume. > > So whether you implement it in C, compile to CLR bytecode, or > translate into > Lisp, the computer is still going to have to to a whole bunch of > lookups to > make certain that there isn't some monkey business going on, rather > than > simply reading a single memory location that contains the length of > the list. > Brett Cannon's thesis is an example: he attempted desperate measures > to > perform some inferences that would allow performing these > optimizations > safely and, although a few of them could work in special cases, most > of the > hoped-for improvements were impossible because of the dynamic nature > of the > language. > > I have seen a number of attempts to address this, either by placing > some > restrictions on the dynamic nature of the code (but that would change > the > nature of the Python language) or by having some sort of a JIT > optimize the > common path where we don't monkey around. Unladen Swallow and PyPy are > two > such efforts that I find particularly promising. > > But it isn't NEARLY as simple as you make it out to be. > > -- Michael Chermside You might be right for the wrong reasons in a way. Python isn't slow because it's a dynamic language. All the lookups you're citing are highly optimized hash lookups. It executes really fast. The OP is talking about scale. Some people say Python is slow at a certain scale. I say that's about true for any language. Large amounts of IO is a tough problem. Where Python might get hit *as a language* is that the Python programmer has to drop into C to implement optimized data-structures for dealing with the kind of IO that would slow down the Python interpreter. That's why we have numpy, scipy, etc. The special cases it takes to solve problems with custom types wasn't special enough to alter the language. Scale is a special case believe it or not. As an implementation though, the sky really is the limit and Python is only getting started. Give it another 40 years and it'll probably realize that it's just another Lisp. ;) -- http://mail.python.org/mailman/listinfo/python-list
Re: python simply not scaleable enough for google?
* Steven D'Aprano: On Thu, 12 Nov 2009 08:35:23 -0800, Joel Davis wrote: obviously the GIL is a major reason it's so slow. http://en.wikipedia.org/wiki/Global_Interpreter_Lock Uh oh... No such "obviously" about it. There have been attempts to remove the GIL, and they lead to CPython becoming *slower*, not faster, for the still common case of single-core processors. And neither Jython nor IronPython have the GIL. Jython appears to scale slightly better than CPython, but for small data sets, is slower than CPython. IronPython varies greatly in performance, ranging from nearly twice as fast as CPython on some benchmarks to up to 6000 times slower! http://www.smallshire.org.uk/sufficientlysmall/2009/05/22/ironpython-2-0-and-jython-2-5-performance-compared-to-python-2-5/ http://ironpython-urls.blogspot.com/2009/05/python-jython-and-ironpython.html Blaming CPython's supposed slowness Hm, this seems religious. Of course Python is slow: if you want speed, pay for it by complexity. It so happens that I think CPython could have been significantly faster, but (1) doing that would amount to creating a new implementation, say, C++Python , and (2) what for, really?, since CPU-intensive things should be offloaded to other language code anyway. on the GIL is superficially plausible but doesn't stand up to scrutiny. The speed of an implementation depends on many factors, and it also depends on *what you measure* -- it is sheer nonsense to talk about "the" speed of an implementation. Different tasks run at different speeds, and there is no universal benchmark. This also seems religious. It's like in Norway it became illegal to market lemon soda, since umpteen years ago it's soda with lemon flavoring. This has to do with the *origin* of the citric acid, whether natural or chemist's concoction, no matter that it's the same chemical. So, some people think that it's wrong to talk about interpreted languages, hey, it should be a "language designed for interpretation", or better yet, "dynamic language", or bestest, "language with dynamic flavor". And slow language, oh no, should be "language whose current implementations are perceived as somewhat slow by some (well, all) people", but of course, that's just silly. Cheers, - Alf -- http://mail.python.org/mailman/listinfo/python-list
Re: #define (from C) in Python
On 12 nov, 18:16, Stefan Behnel wrote: > Santiago Romero, 12.11.2009 17:43: > > > Is there a Python version of C's language #define statements? > > > Example: > > > #define ReadMem( (x) ) memory[ (x) ] > > Yes: > > ReadMem = memory.__getitem__ > > Stefan Well, In the above concrete example, that would work, but I was talking for multiple code lines, like: #define LD_r_n(reg) (reg) = Z80ReadMem(r_PC++) #define LD_rr_nn(reg) r_opl = Z80ReadMem(r_PC); r_PC++; \ r_oph = Z80ReadMem(r_PC); r_PC++; \ reg = r_op #define LOAD_r(dreg, saddreg) (dreg)=Z80ReadMem((saddreg)) #define LOAD_rr_nn(dreg) r_opl = Z80ReadMem(r_PC); r_PC++; \ r_oph = Z80ReadMem(r_PC); r_PC++; \ r_tmpl = Z80ReadMem(r_op); \ r_tmph = Z80ReadMem((r_op)+1); \ dreg=r_tmp #define STORE_nn_rr(dreg) \ r_opl = Z80ReadMem(r_PC); r_PC++;\ r_oph = Z80ReadMem(r_PC); r_PC++; \ r_tmp = dreg; \ Z80WriteMem((r_op),r_tmpl, regs); \ Z80WriteMem((r_op+1),r_tmph, regs) But it seems that is not possible :-( -- http://mail.python.org/mailman/listinfo/python-list
Re: ask a question about the module
> Could not import module "Gnuplot" - it is not installed on your > system. You need to install the Gnuplot.py package. > \easyviz\gnuplot_.py(41) : > Traceback (most recent call last): > File "E:\study\python\commodity modle 10.23.py", line 3, in > import multipleloop as mp > File "E:\study\python\multipleloop.py", line 81, in > from scitools.misc import str2obj > File "C:\Python26\lib\site-packages\scitools\__init__.py", line 67, > in > import sys, std > File "C:\Python26\lib\site-packages\scitools\std.py", line 26, in > > from scitools.easyviz import * > File "C:\Python26\lib\site-packages\scitools\easyviz\__init__.py", > line 1819, in > exec(cmd) > File "", line 1, in > File "C:\Python26\lib\site-packages\scitools\easyviz\gnuplot_.py", > line 42, in > import Gnuplot > ImportError: No module named Gnuplot > > > the above is the hint from python window, I know Gnuplot is a software > and it can help us to make graphs, however, after I download Gnuplot > and run it, the problem still exist. Is there any expert can help me > solve this problem? > Thank you very much! Did you also install the python bindings for gnuplot? If not, you can get it from http://gnuplot-py.sourceforge.net/ HTH, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
