Re: Basic Python Questions - Oct. 31, 2013
E.D.G. edgrs...@ix.netcom.com wrote in message news:yo-dnwfmi7_7d-jpnz2dnuvz_hqdn...@earthlink.com... Posted by E.D.G. on November 12, 2013 The following is part of a note that I just posted to the Perl Newsgroup. But it is actually intended for all computer programmers who are circulating free download software. One of the people that I work with and I are using an important computer program that is quite unique. It was created a long time ago by a highly regarded scientist who passed away a while back. And he made three copies of the program available for people as free downloads. The first is an exe version of the program that will run on any Windows machine. The second is the code for the program written using what is now an ancient version of Fortran. And the third is for the same program using an ancient version of Basic. The professional programmer and I attempted to produce versions of the program using a modern language. I managed the project and the programmer did the actual work. And unfortunately, in spite of his many years of experience he could not understand the Fortran and Basic versions to the point where he could translate them. I recommended that he post some notes to the Fortran Newsgroup and ask if anyone visiting that Newsgroup had an instruction manual for that ancient version of Fortran that would explain what the program code meant. But for some reason he chose not to do that. And it would have taken me a considerable amount of time to attempt the translation myself. So, the end result is that when the program needs to generate data, the exe version is used as is. Or it is called from a Perl program and given the input information it needs so that it can generate data. The point is, when people want to make some computer program available for use by others around the world they might want to circulate a version of their program that has such a simple format that anyone can understand it. And for actual use they can generate parallel versions that have more efficient code that people who are working with that language can understand. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Tue, Nov 12, 2013 at 9:21 PM, E.D.G. edgrs...@ix.netcom.com wrote: The point is, when people want to make some computer program available for use by others around the world they might want to circulate a version of their program that has such a simple format that anyone can understand it. And for actual use they can generate parallel versions that have more efficient code that people who are working with that language can understand. Sounds to me like something out of cryptography. You have a reference implementation that's slow, readable, and straight-forward, and then you have optimized implementations that are actually fast enough to use - but if any time you want to know if you're producing the right output, you just compare against the reference implementation. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Q4, you could try Waterloo Graphics http://waterloo.sourceforge.net. Its LGPLv3 and, although Java-based, runs in Python via Py4J. It has built-in mouse interactivity/GUI editors etc that will all be active when used from Python. It is Java Swing-based, so e.g. data points can be drawn as standard clickable Swing components (see http://waterloo.sourceforge.net/R/scatter.html for an example using R [N.B. not interactive on the web site which just shows a bit-map]). For Python examples see http://waterloo.sourceforge.net/python/grid.html On Thursday, October 31, 2013 9:31:11 AM UTC, E.D.G. wrote: Posted by E.D.G. on October 31, 2013 The following are several relatively basic questions regarding Python's capabilities. I am not presently using it myself. At the moment a number of people including myself are comparing it with other programs such as XBasic for possible use. 1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. 2. Can Python be used to create CGI programs? These are the ones that run on Internet server computers and process data submitted through Web site data entry screens etc. I know that Perl CGI programs will do that. 3. If Python can be used for CGI programming, can it draw charts such as .png files that will then display on Web pages at a Web site? 4. How well does Python work for interactive programming. For example, if a Python program is running on a PC and is drawing a chart, can that chart be modified by simply pressing a key while the Python program is running. I have Perl and Gnuplot program combinations that can do that. Their interactive speed is not that great. But it is adequate for my own uses. 5. Can a running Python program send information to the Windows operating system as if it were typed in from the keyboard? Perl can do that and I would imagine that Python probably has that same capability. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Tuesday, November 5, 2013 1:22:05 PM UTC+8, E.D.G. wrote: Jim Gibson jimsgib...@gmail.com wrote in message news:031120131018099327%jimsgib...@gmail.com... One way to generate plot within a CGI program is this: To start off with, I am not a CGI expert. Also, I have several degrees in the physical sciences and many years of doing computer programming. But the programming work is done just to get various science projects to work. The question that I could not get an answer for was, “How can you get Gnuplot to run on an Internet server computer?” And I would eventually have to ask that same question for Python. My Internet Server looks like it has Perl, Perl5, and PHP available. And I have created a number of CGI Perl programs that run on the Web site. But as I said, I would not know how to get Gnuplot or Python to run at the site. Any recommendations for how to do that? Or should I just do a search for the necessary documentation? Please try modpy. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Jim Gibson jimsgib...@gmail.com wrote in message news:031120131018099327%jimsgib...@gmail.com... One way to generate plot within a CGI program is this: To start off with, I am not a CGI expert. Also, I have several degrees in the physical sciences and many years of doing computer programming. But the programming work is done just to get various science projects to work. The question that I could not get an answer for was, “How can you get Gnuplot to run on an Internet server computer?” And I would eventually have to ask that same question for Python. My Internet Server looks like it has Perl, Perl5, and PHP available. And I have created a number of CGI Perl programs that run on the Web site. But as I said, I would not know how to get Gnuplot or Python to run at the site. Any recommendations for how to do that? Or should I just do a search for the necessary documentation? -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
E.D.G. edgrs...@ix.netcom.com wrote in message news:udgdnadga6n9vu_pnz2dnuvz_umdn...@earthlink.com... Thanks for all of the comments. I have been away from my Internet connection for several days and could not respond to them when they were first posted here. The comments have all been considered. And I am discussing them with other researchers that I work with. Since Perl has a calculation speed limit that is probably not easy to get around, before too long another language will be selected for initially doing certain things such as performing calculations and plotting charts. And the existing Perl code might then be gradually translated into that new language. Gnuplot is presently being used to draw charts. And it works. But it has its own limitations such as with its interaction speed when it is used for working with Perl program generated data files. My main, complex programs won't be run at Web sites. They will instead continue to be available as downloadable exe programs. The CGI (or whatever) programming work would involve relatively simple programs. But they would need to be able to generate charts that would be displayed on Web pages. That sounds like it is probably fairly easy to do using Python. A Perl - Gnuplot combination is also supposed to be able to do that. But so far I have not seen any good explanations for how to actually get Gnuplot to run as a callable CGI program. So other programs such as Python are being considered. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Mark Lawrence breamore...@yahoo.co.uk wrote in message news:mailman.1873.1383227352.18130.python-l...@python.org... https://pypi.python.org/pypi/pywinauto/0.3.9 or http://stackoverflow.com/questions/1823762/sendkeys-for-python-3-1-on-windows Python SendKey looks like it probably works about the same as the Perl version. It prints or sends control information to the active window. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
William Ray Wing w...@mac.com wrote in message news:mailman.1934.1383320554.18130.python-l...@python.org... If you look here: http://wiki.wxpython.org/MatplotlibFourierDemo A suggestion that I would like to add is that when people make Demo programs like that available they might want to create exe versions that people can download and try without installing the original programming language. However, there might have been an exe version at that Web site and I just didn't see it. I myself use expendable backup computers (Windows XP) for testing new exe programs so that problems are not created for my primary computer. If something goes wrong on one of the backup systems it is simply told to go back to an earlier restore point. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Sunday, November 3, 2013 11:15:48 AM UTC+5:30, E.D.G. wrote: rusi wrote: Not sure what will… you may look at Julia: http://julialang.org/ That program language speed comparison table looks quite interesting. And I asked some of the other people that I work with to take a look at the Web page. One or two of them might want to consider using it instead of XBasic assuming the calculation speeds and chart generation capabilities are at least roughly equal. If either of them decides to move in that direction I will probably try using it myself. And please post back your findings when you have some concrete data For the record I have exactly zero experience with Julia. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Sun, 03 Nov 2013 01:02:24 -0500, E.D.G. wrote: [...] Since Perl has a calculation speed limit that is probably not easy to get around, before too long another language will be selected for initially doing certain things such as performing calculations and plotting charts. And the existing Perl code might then be gradually translated into that new language. The nice things about Python are that it makes a great glue language for putting together components written in low-level languages like C and Fortran, and that there is a rich ecosystem of products for speeding it up in various ways. So when you hit the speed limits of pure Python, you have lots of options. In no particular order: * try using another Python compiler: PyPy is probably the most mature of the stand-alone optimizing compilers, and you can expect to double the speed of typical Python code, but there are others; * use numpy and scipy for vectorized mathematical routines; * re-write critical code as C or Fortran libraries; * use Pyrex (possibly unmaintained now) or Cython to write C extensions in a Python-like language; * use Psyco or Numba (JIT specialising compilers for Python); * use Theano (optimizing computer algebra system compiler); * use ctypes to call C functions directly; * use other products like Boost, Weave, and more. See, for example: http://jakevdp.github.io/blog/2013/06/15/numba-vs-cython-take-2/ http://technicaldiscovery.blogspot.com.au/2011/06/speeding-up-python-numpy-cython-and.html -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote in message news:5275fe91$0$29972$c3e8da3$54964...@news.astraweb.com... http://jakevdp.github.io/blog/2013/06/15/numba-vs-cython-take-2/ http://technicaldiscovery.blogspot.com.au/2011/06/speeding-up-python-numpy-cython-and.html It appears that Python can do what is needed. And if the people that I work with want to move in that direction I will probably post a note here stating, This is exactly what we need to do. What would be the best Python download and compiler to do that? It should be a simple matter to determine which compiler and libraries etc. should be used. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 03/11/2013 09:47, E.D.G. wrote: Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote in message news:5275fe91$0$29972$c3e8da3$54964...@news.astraweb.com... http://jakevdp.github.io/blog/2013/06/15/numba-vs-cython-take-2/ http://technicaldiscovery.blogspot.com.au/2011/06/speeding-up-python-numpy-cython-and.html It appears that Python can do what is needed. And if the people that I work with want to move in that direction I will probably post a note here stating, This is exactly what we need to do. What would be the best Python download and compiler to do that? It should be a simple matter to determine which compiler and libraries etc. should be used. I've literally just stumbled across this, I've no idea whether it's of any use to you https://speakerdeck.com/ianozsvald/high-performance-python -- Python is the second best programming language in the world. But the best has yet to be invented. Christian Tismer Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
In article okcdnxfaqqxze-jpnz2dnuvz_jgdn...@earthlink.com, E.D.G. edgrs...@ix.netcom.com wrote: My main, complex programs won't be run at Web sites. They will instead continue to be available as downloadable exe programs. The CGI (or whatever) programming work would involve relatively simple programs. But they would need to be able to generate charts that would be displayed on Web pages. That sounds like it is probably fairly easy to do using Python. A Perl - Gnuplot combination is also supposed to be able to do that. But so far I have not seen any good explanations for how to actually get Gnuplot to run as a callable CGI program. So other programs such as Python are being considered. One way to generate plot within a CGI program is this: 1. Write a file with gnuplot commands (e.g., 'gnuplot.cmd') that set the output device to a graphics file of some format (e.g., PNG), generate a plot, and quit gnuplot. 2. Run gnuplot and point it to the file of commands (e.g., 'gnuplot gunplot.cmd') . How this is done depends upon the CGI program language (see below). 3. Generate HTML that uses the generated graphics file as an embedded image (using the img tag). I have done this in the past, but not recently. This should work for Python (os.system(gnuplot gnuplot.cmd) or Perl (system(gnuplot gnuplot.cmd) with suitable commands to execute external programs. -- Jim Gibson -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Sunday, November 3, 2013 1:13:13 PM UTC+5:30, Steven D'Aprano wrote: On Sun, 03 Nov 2013 01:02:24 -0500, E.D.G. wrote: [...] Since Perl has a calculation speed limit that is probably not easy to get around, before too long another language will be selected for initially doing certain things such as performing calculations and plotting charts. And the existing Perl code might then be gradually translated into that new language. The nice things about Python are that it makes a great glue language for putting together components written in low-level languages like C and Fortran, and that there is a rich ecosystem of products for speeding it up in various ways. So when you hit the speed limits of pure Python, you have lots of options. In no particular order: * try using another Python compiler: PyPy is probably the most mature of the stand-alone optimizing compilers, and you can expect to double the speed of typical Python code, but there are others; * use numpy and scipy for vectorized mathematical routines; * re-write critical code as C or Fortran libraries; * use Pyrex (possibly unmaintained now) or Cython to write C extensions in a Python-like language; * use Psyco or Numba (JIT specialising compilers for Python); * use Theano (optimizing computer algebra system compiler); * use ctypes to call C functions directly; * use other products like Boost, Weave, and more. Yes python is really state-of-art in this respect: Every language will have some area where it sucks. Allowing for a hatch where one could jump out is helpful. Python allows more such hatches than probably any other language (that I know) https://mail.python.org/pipermail/python-list/2012-August/628090.html is a (non exhaustive) list I had made some time. On the other hand if you know you are going to be escaping out often, you may want to consider whether the 'escapee' should be your base rather than python. Which means take something like the pairwise function and code it up in python and julia -- its hardly 10 lines of code. And see what comparative performance you get. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 03/11/2013 18:28, rusi wrote: Which means take something like the pairwise function and code it up in python and julia -- its hardly 10 lines of code. And see what comparative performance you get. Solely on the grounds that you've mentioned julia how about this http://blog.leahhanson.us/julia-calling-python-calling-julia.html -- Python is the second best programming language in the world. But the best has yet to be invented. Christian Tismer Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 2013-11-03, Jim Gibson jimsgib...@gmail.com wrote: In article okcdnxfaqqxze-jpnz2dnuvz_jgdn...@earthlink.com, E.D.G. edgrs...@ix.netcom.com wrote: My main, complex programs won't be run at Web sites. They will instead continue to be available as downloadable exe programs. The CGI (or whatever) programming work would involve relatively simple programs. But they would need to be able to generate charts that would be displayed on Web pages. That sounds like it is probably fairly easy to do using Python. A Perl - Gnuplot combination is also supposed to be able to do that. But so far I have not seen any good explanations for how to actually get Gnuplot to run as a callable CGI program. So other programs such as Python are being considered. One way to generate plot within a CGI program is this: 1. Write a file with gnuplot commands (e.g., 'gnuplot.cmd') that set the output device to a graphics file of some format (e.g., PNG), generate a plot, and quit gnuplot. Or you can use the pygnuplot module which handles much of that for y0ou. http://pygnuplot.sourceforge.net/ -- Grant -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Monday, November 4, 2013 12:28:24 AM UTC+5:30, Mark Lawrence wrote: On 03/11/2013 18:28, rusi wrote: Which means take something like the pairwise function and code it up in python and julia -- its hardly 10 lines of code. And see what comparative performance you get. Solely on the grounds that you've mentioned julia how about this http://blog.leahhanson.us/julia-calling-python-calling-julia.html Good stuff -- thanks -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
rusi rustompm...@gmail.com wrote in message news:1e63687b-4269-42d9-8700-e3a8dcc57...@googlegroups.com... Not sure what will… you may look at Julia: http://julialang.org/ That program language speed comparison table looks quite interesting. And I asked some of the other people that I work with to take a look at the Web page. One or two of them might want to consider using it instead of XBasic assuming the calculation speeds and chart generation capabilities are at least roughly equal. If either of them decides to move in that direction I will probably try using it myself. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Oct 31, 2013, at 5:31 AM, E.D.G. edgrs...@ix.netcom.com wrote: Posted by E.D.G. on October 31, 2013 The following are several relatively basic questions regarding Python's capabilities. I am not presently using it myself. At the moment a number of people including myself are comparing it with other programs such as XBasic for possible use. 1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. [byte] 4. How well does Python work for interactive programming. For example, if a Python program is running on a PC and is drawing a chart, can that chart be modified by simply pressing a key while the Python program is running. I have Perl and Gnuplot program combinations that can do that. Their interactive speed is not that great. But it is adequate for my own uses. I thought about responding to this yesterday, decided others could do so better than I, but then decided to point out a bit of demo code that was one of the first really startling pieces of Python that I stumbled into. If you look here: http://wiki.wxpython.org/MatplotlibFourierDemo You will find a fairly short, well documented demo code that interactively computes a Fast Fourier transform from the frequency domain to the time domain. As you move the two sliders below the graphs, the input aptitude and location of the frequency peaks are changed and the resulting wavelet is plotted, all in real time. Computing a Fourier transform is numerically pretty intensive, doing so in real time with no perceptible delay (at least on a reasonably modern system) should convince any skeptic of Python's ability to do BOTH number crunching AND interactive display. Granted, this performance is based on pulling in libraries. It imports numpy, mathplotlib, and wx to handle the fast array calculations, the plotting, and the GUI respectively, but those are exactly the sorts of batteries included libraries that give Python so much power and flexibility. -Bill -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 11/01/2013 08:42 AM, William Ray Wing wrote: Granted, this performance is based on pulling in libraries. It imports numpy, mathplotlib, and wx to handle the fast array calculations, the plotting, and the GUI respectively, but those are exactly the sorts of batteries included libraries that give Python so much power and flexibility. Not to take away from your points about Python, combined with the appropriate libraries, being fast enough, but the batteries included refers to what comes in the stdlib -- those three libraries are not in the stdlib, so they're more along the lines of power generators easily acquired. :) -- ~Ethan~ -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Nov 1, 2013, at 2:08 PM, Ethan Furman et...@stoneleaf.us wrote: On 11/01/2013 08:42 AM, William Ray Wing wrote: Granted, this performance is based on pulling in libraries. It imports numpy, mathplotlib, and wx to handle the fast array calculations, the plotting, and the GUI respectively, but those are exactly the sorts of batteries included libraries that give Python so much power and flexibility. Not to take away from your points about Python, combined with the appropriate libraries, being fast enough, but the batteries included refers to what comes in the stdlib -- those three libraries are not in the stdlib, so they're more along the lines of power generators easily acquired. :) -- ~Ethan~ -- https://mail.python.org/mailman/listinfo/python-list Strictly speaking, you are absolutely correct. But, those three libraries are SO widely available (for so many platforms), I took the liberty of being inclusive. Thanks, Bill -- https://mail.python.org/mailman/listinfo/python-list
Basic Python Questions - Oct. 31, 2013
Posted by E.D.G. on October 31, 2013 The following are several relatively basic questions regarding Python's capabilities. I am not presently using it myself. At the moment a number of people including myself are comparing it with other programs such as XBasic for possible use. 1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. 2. Can Python be used to create CGI programs? These are the ones that run on Internet server computers and process data submitted through Web site data entry screens etc. I know that Perl CGI programs will do that. 3. If Python can be used for CGI programming, can it draw charts such as .png files that will then display on Web pages at a Web site? 4. How well does Python work for interactive programming. For example, if a Python program is running on a PC and is drawing a chart, can that chart be modified by simply pressing a key while the Python program is running. I have Perl and Gnuplot program combinations that can do that. Their interactive speed is not that great. But it is adequate for my own uses. 5. Can a running Python program send information to the Windows operating system as if it were typed in from the keyboard? Perl can do that and I would imagine that Python probably has that same capability. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Thu, Oct 31, 2013 at 10:31 AM, E.D.G. edgrs...@ix.netcom.com wrote: Posted by E.D.G. on October 31, 2013 The following are several relatively basic questions regarding Python's capabilities. I am not presently using it myself. At the moment a number of people including myself are comparing it with other programs such as XBasic for possible use. 1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. Depends on what do you want to calculate. Also, note that Python is liked by the scientific community to use for calculations. This might be a hint. 2. Can Python be used to create CGI programs? These are the ones that run on Internet server computers and process data submitted through Web site data entry screens etc. I know that Perl CGI programs will do that. Yes. Although most people in the Python community dislike the old-style “CGI” and use “web apps” instead. They are also connected with a different philosophy, for example we do not store .py files in /cgi-bin/, we never expose our .py files and put it somewhere else on the system and let the web server act as a proxy to a WSGI server (gunicorn/uwsgi). 3. If Python can be used for CGI programming, can it draw charts such as .png files that will then display on Web pages at a Web site? Yes, but you need to install additional libraries for that. 4. How well does Python work for interactive programming. For example, if a Python program is running on a PC and is drawing a chart, can that chart be modified by simply pressing a key while the Python program is running. I have Perl and Gnuplot program combinations that can do that. Their interactive speed is not that great. But it is adequate for my own uses. Doable, but I cannot give you any information on the speed. 5. Can a running Python program send information to the Windows operating system as if it were typed in from the keyboard? Perl can do that and I would imagine that Python probably has that same capability. Definitely possible, but might take you a bit of work and knowledge of Windows internals (go ask Google). -- Chris “Kwpolska” Warrick http://kwpolska.tk PGP: 5EAAEA16 stop html mail | always bottom-post | only UTF-8 makes sense -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Posted by E.D.G. October 31, 2013 Hi Chris, Thanks for the responses. Several of my questions were answered. The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. Presently I am using Perl to do those types of calculations. And I am starting to run into problems with how long it takes Perl to do thousands and even millions of calculations like that even though they are relatively simple. The version of Perl that I am presently using has the usual Print statements for printing to the Perl program window. It sends Windows programs or files information in the following manner: Win32::GuiTest::SendKeys(The text within these two parentheses marks will print as text in an active Notepad window.); It would be my guess that Python has some type of statement like that. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Thu, Oct 31, 2013 at 11:38 AM, E.D.G. edgrs...@ix.netcom.com wrote: Posted by E.D.G. October 31, 2013 no need to write that. Hi Chris, Thanks for the responses. Several of my questions were answered. The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. Presently I am using Perl to do those types of calculations. And I am starting to run into problems with how long it takes Perl to do thousands and even millions of calculations like that even though they are relatively simple. I suggest that you try Python out yourself, on your data. I can’t The version of Perl that I am presently using has the usual Print statements for printing to the Perl program window. It sends Windows programs or files information in the following manner: Win32::GuiTest::SendKeys(The text within these two parentheses marks will print as text in an active Notepad window.); It would be my guess that Python has some type of statement like that. Looks like you want something like [0] (requires pywin32 from [1]). [0]: http://win32com.goermezer.de/content/view/136/254/ [1]: http://sourceforge.net/projects/pywin32/files/pywin32/Build%20218/ -- Chris “Kwpolska” Warrick http://kwpolska.tk PGP: 5EAAEA16 stop html mail | always bottom-post | only UTF-8 makes sense -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
In article udgdnadga6n9vu_pnz2dnuvz_umdn...@earthlink.com, E.D.G. edgrs...@ix.netcom.com wrote: 1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. Getting a handle on Python's execution speed is not easy. The problem is that the core library is mostly written in C, so operations that happen inside the core library are fast. Operations that happen in user-written Python code are slow. How fast your overall program will run is largely determined by how much you're executing user code and how much you're executing library calls. People have done lots of comparisons of language execution speed over the years. If you google for python speed comparison, you'll find plenty of more detailed answers than you'll get here. 2. Can Python be used to create CGI programs? These are the ones that run on Internet server computers and process data submitted through Web site data entry screens etc. I know that Perl CGI programs will do that. Yes, they can. However, CGI is largely an obsolete interface, partly because it's so inefficient. If you're worried about execution speed, CGI is not what you should be looking at. 3. If Python can be used for CGI programming, can it draw charts such as .png files that will then display on Web pages at a Web site? Yes. There are a number of modules out there for doing this. Again, google is your friend. Search for python charting module, or variations on that. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). I have never seen any serious use of python for numerical computations without use of numpy/scipy, which is basically a python wrapper around compiled libraries. You probably should consider such a combination. Presently I am using Perl to do those types of calculations. And I am starting to run into problems with how long it takes Perl to do thousands and even millions of calculations like that even though they are relatively simple. No surprise. [...] It sends Windows programs or files information in the following manner: Win32::GuiTest::SendKeys(...); I have no idea on what this could be useful for, but it took me a few seconds to type python sendkeys and get some interesting results. -- Alain. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 31/10/2013 10:38, E.D.G. wrote: Posted by E.D.G. October 31, 2013 Hi Chris, Thanks for the responses. Several of my questions were answered. The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. Presently I am using Perl to do those types of calculations. And I am starting to run into problems with how long it takes Perl to do thousands and even millions of calculations like that even though they are relatively simple. The version of Perl that I am presently using has the usual Print statements for printing to the Perl program window. It sends Windows programs or files information in the following manner: Win32::GuiTest::SendKeys(The text within these two parentheses marks will print as text in an active Notepad window.); It would be my guess that Python has some type of statement like that. https://pypi.python.org/pypi/pywinauto/0.3.9 or http://stackoverflow.com/questions/1823762/sendkeys-for-python-3-1-on-windows of any use? -- Python is the second best programming language in the world. But the best has yet to be invented. Christian Tismer Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Fri, Nov 1, 2013 at 12:17 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). Well, they may not be simple to do, but chances are you can push the work down to the CPU/FPU on most modern hardware - that is, if you're working with IEEE floating point, which I'm pretty sure CPython always does; not sure about other Pythons. No need to actually calculate trig functions unless you need arbitrary precision (and even then, I'd bet the GMP libraries have that all sewn up for you). So the language doesn't make a lot of difference. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 31/10/2013 13:17, Alain Ketterlin wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). From http://docs.python.org/3/library/math.html CPython implementation detail: The math module consists mostly of thin wrappers around the platform C math library functions. There's only one way I know of to find if it's actually fast enough and that's test it. -- Python is the second best programming language in the world. But the best has yet to be invented. Christian Tismer Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Chris Angelico ros...@gmail.com writes: On Fri, Nov 1, 2013 at 12:17 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). Well, they may not be simple to do, but chances are you can push the work down to the CPU/FPU on most modern hardware - that is, if you're working with IEEE floating point, which I'm pretty sure CPython always does; not sure about other Pythons. No need to actually calculate trig functions unless you need arbitrary precision (and even then, I'd bet the GMP libraries have that all sewn up for you). So the language doesn't make a lot of difference. Well, sure, yes, I agree with you and hope they are left to the FP engine (still, fp ops are often multi-cycle, but that's a minor point). But what I meant was: a (bytecode) interpreted program will always be slower than a compiled program, probably by an order of magnitude when doing number crunching. -- Alain. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 2013-10-31 14:05, Chris Angelico wrote: On Fri, Nov 1, 2013 at 12:17 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). Well, they may not be simple to do, but chances are you can push the work down to the CPU/FPU on most modern hardware - that is, if you're working with IEEE floating point, which I'm pretty sure CPython always does; not sure about other Pythons. No need to actually calculate trig functions unless you need arbitrary precision (and even then, I'd bet the GMP libraries have that all sewn up for you). So the language doesn't make a lot of difference. Sure it does. Python boxes floats into a PyObject structure. Both Python and C will ultimately implement the arithmetic of a + b with an FADD instruction, but Python will do a bunch of pointer dereferencing, hash lookups, and function calls before it gets down to that. All of that overhead typically outweighs the floating point computations down at the bottom, even for the more expensive trig functions. This is where numpy comes in. If you can arrange your computation on arrays, then only the arrays need to be unboxed once, then the rest of the arithmetic happens in C. -- 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 -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Fri, Nov 1, 2013 at 1:18 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: Well, sure, yes, I agree with you and hope they are left to the FP engine (still, fp ops are often multi-cycle, but that's a minor point). But what I meant was: a (bytecode) interpreted program will always be slower than a compiled program, probably by an order of magnitude when doing number crunching. Yeah, but it depends on what your number crunching actually involves. If you're implementing crypto in Python, then yes, there's a lot of actual Python number crunching, and it's going to be slow. But calculating the cosine of 1.23456 is going to take very close to the same amount of time in each - the work isn't being done in Python. But yes, Python code does tend to be a lot slower than equivalent C. The goal of Python is not to lick (or even challenge) C for raw speed, but to be fast enough, and to be easy to write and clear to read. It does a fairly good job at that. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Fri, Nov 1, 2013 at 1:41 AM, Robert Kern robert.k...@gmail.com wrote: On 2013-10-31 14:05, Chris Angelico wrote: On Fri, Nov 1, 2013 at 12:17 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). Well, they may not be simple to do, but chances are you can push the work down to the CPU/FPU on most modern hardware - that is, if you're working with IEEE floating point, which I'm pretty sure CPython always does; not sure about other Pythons. No need to actually calculate trig functions unless you need arbitrary precision (and even then, I'd bet the GMP libraries have that all sewn up for you). So the language doesn't make a lot of difference. Sure it does. Python boxes floats into a PyObject structure. Both Python and C will ultimately implement the arithmetic of a + b with an FADD instruction, but Python will do a bunch of pointer dereferencing, hash lookups, and function calls before it gets down to that. All of that overhead typically outweighs the floating point computations down at the bottom, even for the more expensive trig functions. Of course that's true, but that difference is just as much whether you're working with addition or trig functions. That overhead is the same. So if, as I said in the other post, you're doing some heavy crypto work or something, then yes, all that boxing and unboxing is expensive. Most programs aren't doing that, so the advantage is far less (by proportion). Plus, high level languages like Python make it a *LOT* easier to work with arbitrary-precision integers than C does. In Python, you just work with the default integer type and it's infinite-precision. In C, you have to switch to explicitly using GMP (or equivalent). I'd much rather pay the overhead and have the convenience of int being able to store any integer. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
Mark Lawrence breamore...@yahoo.co.uk writes: On 31/10/2013 13:17, Alain Ketterlin wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). From http://docs.python.org/3/library/math.html CPython implementation detail: The math module consists mostly of thin wrappers around the platform C math library functions. Of course, at the end, you need to do the computation. I was not clear enough. I meant: the time taken by the bytecode interpreter is probably larger than the time taken to compute the result (and not only for +). There's only one way I know of to find if it's actually fast enough and that's test it. Whether they are fast enough or not is another question and depends on the application. It seems that the OP feels they are not fast enough (in perl, but I see no reason why it would be better in python). -- Alain. -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On 2013-10-31 14:49, Chris Angelico wrote: On Fri, Nov 1, 2013 at 1:41 AM, Robert Kern robert.k...@gmail.com wrote: On 2013-10-31 14:05, Chris Angelico wrote: On Fri, Nov 1, 2013 at 12:17 AM, Alain Ketterlin al...@dpt-info.u-strasbg.fr wrote: E.D.G. edgrs...@ix.netcom.com writes: The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. These are not simple computations. Any compiled language (Fortran, C, C++, typically) will probably go much faster than any interpreted/bytecode-based language (like python or perl, anything that does not use a jit). Well, they may not be simple to do, but chances are you can push the work down to the CPU/FPU on most modern hardware - that is, if you're working with IEEE floating point, which I'm pretty sure CPython always does; not sure about other Pythons. No need to actually calculate trig functions unless you need arbitrary precision (and even then, I'd bet the GMP libraries have that all sewn up for you). So the language doesn't make a lot of difference. Sure it does. Python boxes floats into a PyObject structure. Both Python and C will ultimately implement the arithmetic of a + b with an FADD instruction, but Python will do a bunch of pointer dereferencing, hash lookups, and function calls before it gets down to that. All of that overhead typically outweighs the floating point computations down at the bottom, even for the more expensive trig functions. Of course that's true, but that difference is just as much whether you're working with addition or trig functions. That overhead is the same. So if, as I said in the other post, you're doing some heavy crypto work or something, then yes, all that boxing and unboxing is expensive. Yes, Alain was wrong to suggest that these are not simple calculations and thus will benefit from a lower-level language. In fact, the relationship is reversed. These are *such* simple operations that they do benefit from the immediate surrounding code being done in C. The amount of time spent on overhead doesn't change based on the operation itself but the immediate surrounding code, the inner loops. That's where the language (implementation) matters. Most programs aren't doing that, so the advantage is far less (by proportion). But we're not talking about most programs. We are talking about the OP's programs, which apparently *do* involve lots of iterated floating point calculations. -- 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 -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
On Thursday, October 31, 2013 4:08:48 PM UTC+5:30, E.D.G. wrote: Posted by E.D.G. October 31, 2013 Hi Chris, Thanks for the responses. Several of my questions were answered. The calculation speed question just involves relatively simple math such as multiplications and divisions and trig calculations such as sin and tan etc. Presently I am using Perl to do those types of calculations. And I am starting to run into problems with how long it takes Perl to do thousands and even millions of calculations like that even though they are relatively simple. If raw machine performance is your main concern, python will likely not will prizes* Not sure what will… you may look at Julia: http://julialang.org/ Some extracts from there: Julia is a dynamic language in the tradition of Lisp, Perl, Python and Ruby. It aims to advance expressiveness and convenience for scientific and technical computing beyond that of environments like Matlab and NumPy, while simultaneously closing the performance gap with compiled languages like C, C++, Fortran and Java. Most high-performance dynamic language implementations have taken an existing interpreted language and worked to accelerate its execution. In creating Julia, we have reconsidered the basic language design, taking into account the capabilities of modern JIT compilers and the specific needs of technical computing. Our design includes: - Multiple dispatch as the core language paradigm. - Exposing a sophisticated type system including parametric dependent types. - Dynamic type inference to generate fast code from programs with no declarations. - Aggressive specialization of generated code for types encountered at run-time. Julia feels light and natural for data exploration and algorithm prototyping, but has performance that lets you deploy your prototypes. * Considering my recent posts treat python as a given, Im not being consistent. Must be getting senile :D -- https://mail.python.org/mailman/listinfo/python-list
Re: Basic Python Questions - Oct. 31, 2013
1. How fast can Python do math calculations compared with other languages such as Fortran and fast versions of Basic. I would have to believe that it is much faster than Perl for doing math calculations. As others have indicated, a lot depends on the form of your calculations. There is a cost to crossing the Python/C boundary, and you may or may not care about the other stuff Python can do on-the-fly, like promote ints to Python longs, check for zero division, etc. If you have floating point code that is array-like, then organizing it to use numpy can be a big win, as you will cross that expensive boundary much less often per underlying operation. (I'm thinking here of more complex operations like trigonometric functions, not simple adds and subtracts, which are handled by the Python virtual machine.) I will relate one anecdote from my job here which highlights the cost of the boundary. I work at a trading firm. I work solely within a Python world, but my stuff is built on top of a lot of C++ code developed by others at the firm. Several years ago, it was decided that we needed a price library because some exchanges (the London Stock Exchange, for example) sets the minimum price change based on the current trading price range. Consider a stock like AAPL, which closed yesterday at 489.56. It trades in pennies on NASDAQ, no matter its price. If it was on the LSE, it might trade in half pennies if it was trading in a $100 range, or in dimes if it was trading near $1000 range. (I'm making this stuff up, just to give you an idea what I'm referring to.) So, a price library was written in C++. You could ask for the next higher or lower valid price. It was all very peppy, because of course, it relied heavily on C++ inline functions for all these simple operations. It was wrapped with Boost::Python and tossed over the fence for us Python peons to use. Guess what? It was unbearably slow, because not only did we were crossing the Python/C boundary to do little more (most of the time) than a single add or subtract. The solution was to write a pure Python version of the parts that mattered most. Moral of the story: consider how your code is structured and whether it makes sense to reorganize it when implementing in Python. Skip -- https://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
Hendrik van Rooyen [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] [EMAIL PROTECTED] wrote: I am currently going to school at Utah Valley State College, the course that I am taking is analysis of programming languages. It's an upper division course but our teacher wanted to teach us python as part of what does upper division mean in this context ? I am unfamiliar with the term. - Hendrik In a 4-year college program in the US, an upper division course is an advanced course, usually reserved for those in the 3rd or 4th years. -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
Paddy wrote: John Machin wrote: [Aside] How are you going to explain all this to your instructor, who may be reading all this right now? The instructor should be proud! He has managed to do his very first post to a this newsgroup, about a homework question, and do it in the right way. that is no mean feat. - Paddy. In fact, he may well by now know more than his instructor, and be explaining the finer points of Python :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
I normaly try to be as resourceful as I can. I find that newgroups give a wide range of answers and solutions to problems and you get a lot responses to what is the right way to do things and different point of views about the language that you can't find in help manuals. I also want to thank everyone for being so helpful in this group, it has been one of the better groups that I have used. John Machin wrote: Paddy wrote: John Machin wrote: [Aside] How are you going to explain all this to your instructor, who may be reading all this right now? The instructor should be proud! He has managed to do his very first post to a this newsgroup, about a homework question, and do it in the right way. that is no mean feat. - Paddy. In fact, he may well by now know more than his instructor, and be explaining the finer points of Python :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
Diez B. Roggisch a écrit : [EMAIL PROTECTED] schrieb: I have taken the coments and think I have implemented most. My only Unfortunately, no. question is how to use the enumerator. Here is what I did, I have tried a couple of things but was unable to figure out how to get the line number. def Xref(filename): try: fp = open(filename, r) except: raise Couldn't read input file \%s\ % filename You still got that I-catch-all-except in there. This will produce subtle bugs when you e.g. misspell a variable name: filename = '/tmp/foo' try: f = open(fliename, 'r') except: raise can't open filename Please notice the wrong-spelled 'fliename'. This OTOH will give you more clues on what really goes wrong: filename = '/tmp/foo' try: f = open(fliename, 'r') except IOError: raise can't open filename And this would be still more informative (and not deprecated...): filename = '/tmp/foo' f = open(fliename) Catching an exception just to raise a less informative one is somewhat useless IMHO. -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
In [EMAIL PROTECTED],
[EMAIL PROTECTED] wrote:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
Instead of reading the file completely into a list you can iterate over
the (open) file object and the `enumerate()` function can be used to get
an index number for each line.
if lines[line_num] == : continue
Take a look at the lines you've read and you'll see why the ``continue``
is never executed.
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
Instead of dealing with words that appear more than once in a line you may
use a `set()` to remove duplicates before entering the loop.
Ciao,
Marc 'BlackJack' Rintsch
--
http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote:
I have a simple assignment for school but am unsure where to go. The
assignment is to read in a text file, split out the words and say which
line each word appears in alphabetical order. I have the basic outline
of the program done which is:
looks like an excellent start to me.
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
if lines[line_num] == : continue
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
return dict
My question is, how do I easily parse out punction marks
it depends a bit how you define the term word.
if you're using regular text, with a limited set of punctuation
characters, you can simply do e.g.
word = word.strip(.,!?:;)
if not word:
continue
inside the for word loop. this won't handle such characters if they
appear inside words, but that's probably good enough for your task.
another, slightly more advanced approach is to use regular expressions,
such as re.findall(\w+) to get a list of all alphanumeric words in
the text. that'll have other drawbacks (e.g. it'll split up words like
couldn't and cross-reference, unless you tweak the regexp), and is
probably overkill.
and how do I sort the list and
how to sort the dictionary when printing the cross-reference, you mean?
just use sorted on the dictionary; that'll get you a sorted list
of the keys.
sorted(dict)
to avoid duplicates and simplify sorting, you probably want to normalize
the case of the words you add to the dictionary, e.g. by converting all
words to lowercase.
if there anything else that I am doing wrong in this code
there's plenty of things that can be tweaked and tuned and written in a
slightly shorter way by an experienced Python programmer, but assuming
that this is a general programming assignment, I don't see something
seriously wrong in your code (just make sure you test it on a file
that doesn't exist before you hand it in)
/F
--
http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] I have a simple assignment for school but am unsure where to go. The assignment is to read in a text file, split out the words and say which line each word appears in alphabetical order. I have the basic outline of the program done which is: And in general, this is one of the best can anyone help me with my homework? posts I've ever seen. A. You told us up front that it was your homework. B. You made an honest stab at the solution before posting, and posted the actual code. C. You ended with some specific questions on things that didn't work or that you wanted to improve. Your current program looks like at least A- material. Add use of sorted and enumerate, and handle that exception a little better, and you're getting into A+ territory. Out of curiosity, what school are you attending that is teaching Python, and under what course of study? -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
I am currently going to school at Utah Valley State College, the course that I am taking is analysis of programming languages. It's an upper division course but our teacher wanted to teach us python as part of the course, he spent about 2 - 3 weeks on python which has been good. I currently work with .net and it is fun to see what other languages have and what sytax they use. Paul McGuire wrote: [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] I have a simple assignment for school but am unsure where to go. The assignment is to read in a text file, split out the words and say which line each word appears in alphabetical order. I have the basic outline of the program done which is: And in general, this is one of the best can anyone help me with my homework? posts I've ever seen. A. You told us up front that it was your homework. B. You made an honest stab at the solution before posting, and posted the actual code. C. You ended with some specific questions on things that didn't work or that you wanted to improve. Your current program looks like at least A- material. Add use of sorted and enumerate, and handle that exception a little better, and you're getting into A+ territory. Out of curiosity, what school are you attending that is teaching Python, and under what course of study? -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
I have taken the coments and think I have implemented most. My only
question is how to use the enumerator. Here is what I did, I have tried
a couple of things but was unable to figure out how to get the line
number.
def Xref(filename):
try:
fp = open(filename, r)
except:
raise Couldn't read input file \%s\ % filename
dict = {}
line_num=0
for words in iter(fp.readline,):
words = set(words.split())
line_num = line_num+1
for word in words:
word = word.strip(.,!?:;)
if not dict.has_key(word):
dict[word] = []
dict[word].append(line_num)
fp.close()
keys = sorted(dict);
for key in keys:
print key, : , dict[key]
return dict
Marc 'BlackJack' Rintsch wrote:
In [EMAIL PROTECTED],
[EMAIL PROTECTED] wrote:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
Instead of reading the file completely into a list you can iterate over
the (open) file object and the `enumerate()` function can be used to get
an index number for each line.
if lines[line_num] == : continue
Take a look at the lines you've read and you'll see why the ``continue``
is never executed.
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
Instead of dealing with words that appear more than once in a line you may
use a `set()` to remove duplicates before entering the loop.
Ciao,
Marc 'BlackJack' Rintsch
--
http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote:
I have taken the coments and think I have implemented most. My only
question is how to use the enumerator. Here is what I did, I have tried
a couple of things but was unable to figure out how to get the line
number.
Try this in the interpreter,
l = [5,4,3,2,1]
for count, i in enumerate(l):
print count, i
def Xref(filename):
try:
fp = open(filename, r)
except:
raise Couldn't read input file \%s\ % filename
dict = {}
line_num=0
for words in iter(fp.readline,):
words = set(words.split())
line_num = line_num+1
for word in words:
word = word.strip(.,!?:;)
if not dict.has_key(word):
dict[word] = []
dict[word].append(line_num)
fp.close()
keys = sorted(dict);
for key in keys:
print key, : , dict[key]
return dict
Marc 'BlackJack' Rintsch wrote:
In [EMAIL PROTECTED],
[EMAIL PROTECTED] wrote:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
Instead of reading the file completely into a list you can iterate over
the (open) file object and the `enumerate()` function can be used to get
an index number for each line.
if lines[line_num] == : continue
Take a look at the lines you've read and you'll see why the ``continue``
is never executed.
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
Instead of dealing with words that appear more than once in a line you may
use a `set()` to remove duplicates before entering the loop.
Ciao,
Marc 'BlackJack' Rintsch
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Re: basic python questions
tom wrote:
[EMAIL PROTECTED] wrote:
I have taken the coments and think I have implemented most. My only
question is how to use the enumerator. Here is what I did, I have tried
a couple of things but was unable to figure out how to get the line
number.
Try this in the interpreter,
l = [5,4,3,2,1]
for count, i in enumerate(l):
print count, i
you could do it like this.
for count, line in enumerate(fb):
for word in line.split():
etc...
filehandles are iterators themselves.
dont take my words for granted though, i'm kinda new to all this too :)
def Xref(filename):
try:
fp = open(filename, r)
except:
raise Couldn't read input file \%s\ % filename
dict = {}
line_num=0
for words in iter(fp.readline,):
words = set(words.split())
line_num = line_num+1
for word in words:
word = word.strip(.,!?:;)
if not dict.has_key(word):
dict[word] = []
dict[word].append(line_num)
fp.close()
keys = sorted(dict);
for key in keys:
print key, : , dict[key]
return dict
Marc 'BlackJack' Rintsch wrote:
In [EMAIL PROTECTED],
[EMAIL PROTECTED] wrote:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
Instead of reading the file completely into a list you can iterate over
the (open) file object and the `enumerate()` function can be used to get
an index number for each line.
if lines[line_num] == : continue
Take a look at the lines you've read and you'll see why the ``continue``
is never executed.
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
Instead of dealing with words that appear more than once in a line you may
use a `set()` to remove duplicates before entering the loop.
Ciao,
Marc 'BlackJack' Rintsch
--
http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] schrieb: I have taken the coments and think I have implemented most. My only Unfortunately, no. question is how to use the enumerator. Here is what I did, I have tried a couple of things but was unable to figure out how to get the line number. def Xref(filename): try: fp = open(filename, r) except: raise Couldn't read input file \%s\ % filename You still got that I-catch-all-except in there. This will produce subtle bugs when you e.g. misspell a variable name: filename = '/tmp/foo' try: f = open(fliename, 'r') except: raise can't open filename Please notice the wrong-spelled 'fliename'. This OTOH will give you more clues on what really goes wrong: filename = '/tmp/foo' try: f = open(fliename, 'r') except IOError: raise can't open filename Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote:
dict = {}
As a general rule you should avoid variable names which shadow built in
types (list, dict, etc.). This can cause unexpected behavior later on.
Also, variable names should be more descriptive of their contents.
Try word_dict or some such variant
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Re: basic python questions
So I implemented the exception spcified and in testing it returns: DeprecationWarning: raising a string exception is deprecated I am not to worried about depreciation warning however, out of curiosity, what would the better way be to handle this? Is there a way that (web site, help documentation, etc...) I would be able to find this? I am running this in Python 2.5 Diez B. Roggisch wrote: [EMAIL PROTECTED] schrieb: I have taken the coments and think I have implemented most. My only Unfortunately, no. question is how to use the enumerator. Here is what I did, I have tried a couple of things but was unable to figure out how to get the line number. def Xref(filename): try: fp = open(filename, r) except: raise Couldn't read input file \%s\ % filename You still got that I-catch-all-except in there. This will produce subtle bugs when you e.g. misspell a variable name: filename = '/tmp/foo' try: f = open(fliename, 'r') except: raise can't open filename Please notice the wrong-spelled 'fliename'. This OTOH will give you more clues on what really goes wrong: filename = '/tmp/foo' try: f = open(fliename, 'r') except IOError: raise can't open filename Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
So I implemented the exception spcified and in testing it returns: DeprecationWarning: raising a string exception is deprecated I am not to worried about depreciation warning however, out of curiosity, what would the better way be to handle this? Is there a way that (web site, help documentation, etc...) I would be able to find this? I am running this in Python 2.5 Diez B. Roggisch wrote: [EMAIL PROTECTED] schrieb: I have taken the coments and think I have implemented most. My only Unfortunately, no. question is how to use the enumerator. Here is what I did, I have tried a couple of things but was unable to figure out how to get the line number. def Xref(filename): try: fp = open(filename, r) except: raise Couldn't read input file \%s\ % filename You still got that I-catch-all-except in there. This will produce subtle bugs when you e.g. misspell a variable name: filename = '/tmp/foo' try: f = open(fliename, 'r') except: raise can't open filename Please notice the wrong-spelled 'fliename'. This OTOH will give you more clues on what really goes wrong: filename = '/tmp/foo' try: f = open(fliename, 'r') except IOError: raise can't open filename Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote: So I implemented the exception spcified and in testing it returns: DeprecationWarning: raising a string exception is deprecated I am not to worried about depreciation warning however, out of curiosity, what would the better way be to handle this? Is there a way that (web site, help documentation, etc...) I would be able to find this? I am running this in Python 2.5 Just try shortening the statement to the bare: raise For example: | try: | ...f = open(nonesuch.txt) | ... except IOError: | ...raise | ... | Traceback (most recent call last): | File stdin, line 2, in module # Coming from a file you'll get filename, linenumber, function/method above | IOError: [Errno 2] No such file or directory: 'nonesuch.txt' | If you feel that the error message that you get is descriptive enough, even better than what you'd contemplated writing yourself, you're done. Otherwise you need to raise an instance of the Exception class, and the degree of difficulty just went up a notch. [Aside] How are you going to explain all this to your instructor, who may be reading all this right now? Cheers, John Diez B. Roggisch wrote: [EMAIL PROTECTED] schrieb: I have taken the coments and think I have implemented most. My only Unfortunately, no. question is how to use the enumerator. Here is what I did, I have tried a couple of things but was unable to figure out how to get the line number. def Xref(filename): try: fp = open(filename, r) except: raise Couldn't read input file \%s\ % filename You still got that I-catch-all-except in there. This will produce subtle bugs when you e.g. misspell a variable name: filename = '/tmp/foo' try: f = open(fliename, 'r') except: raise can't open filename Please notice the wrong-spelled 'fliename'. This OTOH will give you more clues on what really goes wrong: filename = '/tmp/foo' try: f = open(fliename, 'r') except IOError: raise can't open filename Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
John Machin wrote: [Aside] How are you going to explain all this to your instructor, who may be reading all this right now? The instructor should be proud! He has managed to do his very first post to a this newsgroup, about a homework question, and do it in the right way. that is no mean feat. - Paddy. -- http://mail.python.org/mailman/listinfo/python-list
Re: basic python questions
[EMAIL PROTECTED] wrote: I am currently going to school at Utah Valley State College, the course that I am taking is analysis of programming languages. It's an upper division course but our teacher wanted to teach us python as part of what does upper division mean in this context ? I am unfamiliar with the term. - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
basic python questions
I have a simple assignment for school but am unsure where to go. The
assignment is to read in a text file, split out the words and say which
line each word appears in alphabetical order. I have the basic outline
of the program done which is:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
if lines[line_num] == : continue
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
return dict
My question is, how do I easily parse out punction marks and how do I
sort the list and if there anything else that I am doing wrong in this
code it would be much help.
--
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Re: basic python questions
[EMAIL PROTECTED] wrote:
I have a simple assignment for school but am unsure where to go. The
assignment is to read in a text file, split out the words and say which
line each word appears in alphabetical order. I have the basic outline
of the program done which is:
def Xref(filename):
try:
fp = open(filename, r)
lines = fp.readlines()
fp.close()
except:
raise Couldn't read input file \%s\ % filename
dict = {}
for line_num in xrange(len(lines)):
if lines[line_num] == : continue
words = lines[line_num].split()
for word in words:
if not dict.has_key(word):
dict[word] = []
if line_num+1 not in dict[word]:
dict[word].append(line_num+1)
return dict
My question is, how do I easily parse out punction marks and how do I
sort the list and if there anything else that I am doing wrong in this
code it would be much help.
Hi,
on first reading, you have a naked except clause that catches all
exceptions. You might want to try your program on a non-existent file
to find out the actual exception you need to trap for that error
message. Do you want the program to continue if you have no input file?
If you have not covered Regular Expressions, often called RE's then one
way of getting rid of puctuation is to turn the problem on its head.
create a string of all the characters that you consider as valid in
words then go through each input line discarding any character not *in*
the string. Use the doctored line for word extraction.
help(sorted) will start you of on sorting in python. Other
documentation sources have a lot more.
P.S. I have not run the code myself
P.P.S. Where is the functions docstring!
P.P.P.S. You might want to read up on enumerate. It gives another way
to do things when you want an index as well as each item from an
iterable but remember, the index given starts from zero.
Oh, and welcome to comp.lang.python :-)
- Paddy.
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