[Tutor] boa constructor font?
my eyes are going bad... anyone know how to change the font size in the editor window of the boa constructor? this seems to be a simple but not easy thing to do. thanks! Jeff___ Tutor maillist - [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/tutor
[Tutor] os.popen4 help!
Hello, I'm trying to run an executable file from a python script. the executable is "opcenum.exe". OPCENUM.EXE is an executable that is usually found on computers with OPC software; such as OPC Servers or OPC Clients. The purpose of OPCENUM.EXE is to provide an interface into the local machine's Component Category Manager that can be accessed by remote OPC clients over DCOM. OPCEnum.exe provides several useful methods IOPCServerList::EnumClassesofCategory - gets available OPC servers for a specified category of OPC server I want to use IOPCServerList::EnumClassesofCategory but I am having some trouble. currently I do the below: import os cmd = 'opcenum.exe/IOPCServerList/EnumClassesofCategory 63D5F432-CFE4-11d1-B2C8-0060083BA1FB' fin,fout = os.popen4(cmd) result = fout.read() this doesn't work, and it hangs up on fout.read(). I'm do not understand the syntax of the arguments in popen4, i.e., I'm using slashes to get to the EnumClassesofCategory method, but should I use periods or what. The long number at the end is the argument to EnumClassesofCategory, and is the component category CLSID. details are here: http://opcactivex.com/Support/General/OPCEnum/opcenum.html how can I improve things here? thanks, Jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] browing windows registry
hello, I want to browse the windows registry for the program ids listed under the categories: 63D5F430-CFE4-11d1-B2C8-0060083BA1FB 63D5F432-CFE4-11d1-B2C8-0060083BA1FB where might be the best way to learn how to do that with python? thanks, Jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] how do I post event to thread?
hello, I've read a bit about multi thread communication, and found that most people use a queue, which makes sense. however in my case I simply have two threads, a main thread and one other. the main thread is doing many different things and the second thread is receiving numerical data via a serial port.. when data comes in, I want to post the data to the main thread so it can use the it. I don't want to use a queue because I don't want to lock up my main thread in a loop that is always looking at the queue waiting to get something out of it. I would prefer to do something like post an event. The alternative would be to simply have a method in my main thread called OnResult(data), and when data comes in to the second thread I could call main_thread.OnResult(data). This would solve my problem, but I'm not sure if that is an ok thing to do... calling a main thread method from within a second thread? is there a way to post an event to the main thread from a second thread? Is it ok to pass the main thread (self) into the second thread and have the second thread call a main_thread.OnResult(data) method to pass the data into the main thread? I'm not sure how the main thread handles this, my guess is that it can only do one thing at a time so it might be exactly that same as 'posting an event'. any thoughts would be much appreciated. thanks! Jeff ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] how do I post event to thread?
Hi, thanks for all the good responses. I appreciate your thoughts. I was sightly confused about how these threads work together. I am using python 2.6, no GUI at the moment, so I can't use the wxEvent class or the equivalent. The program basically pulls data from a serial port and then calculates some stats and writes data to a file. eventually I will put a GUI on it. I think you are correct that since my logic is in its own thread I can put a portion of code that watches the queue. Thanks for the advice! Jeff --- On Thu, 8/27/09, Kent Johnson wrote: From: Kent Johnson Subject: Re: [Tutor] how do I post event to thread? To: "Jeff Peery" Cc: tutor@python.org Date: Thursday, August 27, 2009, 4:00 AM On Wed, Aug 26, 2009 at 9:38 PM, Jeff Peery wrote: > hello, > I've read a bit about multi thread communication, and found that most people > use a queue, which makes sense. however in my case I simply have two > threads, a main thread and one other. the main thread is doing many > different things and the second thread is receiving numerical data via a > serial port. when data comes in, I want to post the data to the main thread > so it can use the it. I don't want to use a queue because I don't want to > lock up my main thread in a loop that is always looking at the queue waiting > to get something out of it. I would prefer to do something like post an > event. The alternative would be to simply have a method in my main thread > called OnResult(data), and when data comes in to the second thread I could > call main_thread.OnResult(data). This would solve my problem, but I'm not > sure if that is an ok thing to do... calling a main thread method from > within a second thread? As Dave explained, this will run OnResult() in the data thread. > is there a way to post an event to the main thread from a second thread? There is no way I know of to just force a function to run in another thread. The main thread needs to poll in some way for a notification from the data thread. If the main thread is running a GUI toolkit, there is probably a way for the data thread to post an event to the main thread. Most GUI toolkits also have idle loop callbacks so you could schedule an idle task to look for data from the data thread. Does your current main thread have an idle loop where you could poll the queue for data? Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] thread causes idle to crash
hello, I've been working on threads and queues and I think I have it working well. The problem seems to be that when I run a thread via the IDLE it crashes. if I simply double click the file it appears to run ok. I'm not sure if I'm doing something incorrectly or not. it seems pretty straight forward. my sample code is listed below. I'm using Python 2.6.2, and I'm running on Microsoft Vista. Any thoughts would be much appreciated. thanks! Jeff import threading import Queue import time, random WORKERS = 2 class Worker(threading.Thread): def __init__(self, queue): self.__queue = queue threading.Thread.__init__(self) def run(self): while 1: item = self.__queue.get() if item is None: break # reached end of queue # pretend we're doing something that takes 10-100 ms time.sleep(random.randint(10, 100) / 100.0) print "task", item, "finished" # # try it queue = Queue.Queue(0) for i in range(WORKERS): print 'starting' Worker(queue).start() # start a worker for i in range(10): print 'putting' queue.put(i) for i in range(WORKERS): print 'putting None' queue.put(None) # add end-of-queue markers ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] python queue
Hello, Does anyone know if there is there a way to look at a queue's contents? Or prevent duplicate messages from being put into a queue? The docs don't show anything useful. The reason is that I'm collecting and drawing data. one thread collects, and one thread draws. each time one sample is collected by the collector thread, a "draw message" is put into the queue to notify the drawing thread. the dataset is shared between the threads and is continuously growing as data is appended. The queue is used to notify the drawing thread that it should draw. I use threading.Lock() to prevent any "sharing issues". The problem is that if the data collector thread is putting messages into the queue faster than the drawing thread is getting them, then the drawing thread is forced to redraw more times than it needs to and appears slow. However since the dataset is shared the drawing thread only needs to draw once to be updated for all the new samples. For example if 10 samples have been appended by the data collector thread while the drawing thread drew once, then there are now 10 messages for the drawing thread to get. yet it only needs to draw once to reflect the 10 samples. so there are 9 redraws that are a waste of energy. I was hoping there was some feature in the queue class the would prevent or discard a duplicate message. This way my drawing thread won't draw more than it needs to. thanks! Jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] numpy and py2exe
Hello I have a python app that uses wxPython, numpy, and I'm trying to package
it with py2exe. I get the below error. I tried putting a dummy __init__.py file
in the distutils.tests directory but this did not solve the problem. how may I
fix this?
*** searching for required modules ***
Traceback (most recent call last):
File "C:\Users\Jeff\Documents\Working\App\setup.py", line 298, in
cmdclass = {"py2exe": build_installer},
File "C:\Python26\lib\distutils\core.py", line 152, in setup
dist.run_commands()
File "C:\Python26\lib\distutils\dist.py", line 975, in run_commands
self.run_command(cmd)
File "C:\Python26\lib\distutils\dist.py", line 995, in run_command
cmd_obj.run()
File "C:\Users\Jeff\Documents\Working\App\setup.py", line 273, in run
py2exe.run(self)
File "C:\Python26\lib\site-packages\py2exe\build_exe.py", line 243, in run
self._run()
File "C:\Python26\lib\site-packages\py2exe\build_exe.py", line 296, in _run
self.find_needed_modules(mf, required_files, required_modules)
File "C:\Python26\lib\site-packages\py2exe\build_exe.py", line 1342, in find_n
eeded_modules
mf.import_hook(package, None, ["*"])
File "C:\Python26\lib\site-packages\py2exe\mf.py", line 719, in import_hook
return Base.import_hook(self,name,caller,fromlist,level)
File "C:\Python26\lib\site-packages\py2exe\mf.py", line 137, in import_hook
m = self.load_tail(q, tail)
File "C:\Python26\lib\site-packages\py2exe\mf.py", line 217, in load_tail
raise ImportError, "No module named " + mname
ImportError: No module named numpy.distutils.tests
thanks,
Jeff
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[Tutor] py2exe
hello, I am using py2exe. for most of my applications it has been great. although this last one I built and when I try to execute it I get an error: RunTime Error: this application has requested the runtime to terminate in an unusual way. please contact the applications support team for more info. does anyone know what this means? thanks. Jeff ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] py2exe
Ok, thanks again Greg. Although I didn't see a log file, where would it appear and what would the name be... just in case I missed it. thanks. JeffGreg Hasseler <[EMAIL PROTECTED]> wrote: I meant to send my first reply the list..oops. If it doesn't leave anylog file then I would suggest maybe sending the program source codeitself to the list so that others can review it for potential error.On 4/18/05, Jeff Peery <[EMAIL PROTECTED]>wrote:> Hi Greg, thanks for the help. the program does not launch, it crashes> immediately, and I did not see a log file. I also ran py2exe several times> over and always the same result. the program runs great in regular python> mode. any ideas? thanks. > > Jeff> > Greg Hasseler <[EMAIL PROTECTED]>wrote: > Does the application launch at all or does it just immediately crash?> Look and see if there are any logs available. You may also consider> running py2exe again.> > On 4/15/05, Jeff Peery wrote:> > > ! > hello, I am using py2exe. for most of my applications it has been great.> > although this last one I built and when I try to execute it I get an> error: > > > > RunTime Error: this application has requested the runtime to terminate in> an> > unusual way. please contact the applications support team for more info. > > > > does anyone know what this means? thanks. > > > > Jeff > > > > > > ___> > Tutor maillist - Tutor@python.org> > http://mail.python.org/mailman/listinfo/tutor> > > > > >>___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] py2exe
I am using python 2.3.4. thanks. JeffGreg Hasseler <[EMAIL PROTECTED]> wrote: Hi Jeff. I can't tell if you sent the last email to just me or me andthe list, but make sure to send it to the list (don't just hit reply).Also, what version of wxPython are you using?On 4/21/05, Jeff Peery <[EMAIL PROTECTED]>wrote:> > OK, thanks again. I attached my code. I if anyone has an idea as to why the> executable fails after running py2exe please let me know. thanks for the> help! > > Jeff> > Greg Hasseler <[EMAIL PROTECTED]>wrote: > If the application was named test.exe, I find that they are typically> named test.exe.log then or similar.> > On 4/19/05, Jeff Peery wrote:> > Ok, thanks again Greg. Although I didn't see a log file, where would it> > appear and what would the name be... just in case I missed it. thanks. > > > &! gt; Jeff> > > > Greg Hasseler wrote: > > I meant to send my first reply the list..oops. If it doesn't leave any> > log file then I would suggest maybe sending the program source code> > itself to the list so that others can review it for potential error.> > > > > > On 4/18/05, Jeff Peery wrote:> > > Hi Greg, thanks for the help. the program does not launch, it crashes> > > immediately, and I did not see a log file. I also ran py2exe several> times> > > over and always the same result. the program runs great in regular> python> > > mode. any ideas? thanks. > > > > > > Jeff> > > > > > Greg Hasseler wrote: > > > Does the application launch at all or does it just immediately crash?> > > Look and see if there are any logs available. You may also consider> ! > > running py2exe again.> > > > > > On 4/15/05, Jeff Peery wrote:> > > > > > > ! > hello, I am using py2exe. for most of my applications it has been> > great.> > > > although this last one I built and when I try to execute it I get an> > > error: > > > > > > > > RunTime Error: this application has requested the runtime to terminate> > in> > > an> > > > unusual way. please contact the applications support team for more> info.> > > > > > > > does anyone know what this means? thanks. > > > > > > > > Jeff > > > > > > > > > > > > ___> > > > Tutor maillist - Tutor@python.org> > > > http://mail.python.org/mailman/listinfo/tutor! > > > > > > > > > > > >> > >> > > > ___> > Tutor maillist - Tutor@python.org> > http://mail.python.org/mailman/listinfo/tutor> > > > > >> >___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] missing module?
Hello, I get an error message from py2exe that it can't find a module ntpath.py. I pasted the error message below: Traceback (most recent call last): File "wxApp1.py", line 4, in ? File "wx\__init__.pyc", line 42, in ? File "wx\_core.pyc", line 4, in ? File "wx\_core_.pyc", line 9, in ? File "wx\_core_.pyc", line 3, in __load File "C:\Python24\lib\os.py", line 62, in ? import ntpath as pathzipimport.ZipImportError: can't find module 'ntpath' I can find ntpath why can't py2exe? how can I get this thing working? thanks for the help. jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] wxpython error when upgrading?
hello, I recently upgraded my wxpython to 2.5, now I get an error message when I try to edit a dialog in the boa constructor that says : collection body not in init, body, fin form - anyone have an idea what this means? thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] printing documents
hello, I am writing a program to store name/contact/business transaction information. I would like the ability to print out a form for each client with all this stored information. Can somone point me in the write direction for printing documents. How do I go about setting up a printable page with all the variables I have for each client? thanks Also I would like to take the information I input and store it as an images. Essentially take the above mentioned document (the one I want to print out a hard copy) and save it as an image so I can view it later. Any ideas? I'm operating on windows and I'm using wxpython. thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] passing variables between frames?
Hello, I am having trouble with passing variables between frames (Frame1 and Dialog1). I'm using wxpython to write an application. when I run my application the parent frame appears and within the parent frame I can assign values to variables. I then have a button that launches a child dialog. I want to access the values from the parent frame in the dialog. for example say I had a listbox in the parent frame and I choose the first entry 'a' from the list. I then launch the child dialog and I want to put the value of the selection from the list box into a text field - when I lauch the child dialog a text field appears with the value '0'. From within Frame1 I can use the getselection() function to get the listbox selection. although in the child dialog I tried to use Frame1.listBox.getselection() to get the selection from Frame1. this doesn't work. not sure what to do here? any ideas? thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] passing variables between frames?
ok, thanks. that makes sense; however I do not know how to pass a variable from my parent frame to the dialog. I have tried this before unsuccessfully. could you provide a quick example of how to pass a variable to a dialog from a frame. I am not sure how this works. thanks. JeffKent Johnson <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:> Hello, I am having trouble with passing variables between frames (Frame1 > and Dialog1). I'm using wxpython to write an application. when I run my > application the parent frame appears and within the parent frame I can > assign values to variables. I then have a button that launches a child > dialog. I want to access the values from the parent frame in the > dialog. for example say I had a listbox in the parent frame and I > choose the first entry 'a' from the list. I then launch the child > dialog and I want to put the value of the selection from the list box > into a text field - when I lauch the child dialog a text field appears > with the value '0'. From within Frame1 I can use the getselection() > function to get the listbox selection. although in the child dialog I > ! tried to use Frame1.listBox.getselection() to get the selection from > Frame1. this doesn't work. not sure what to do here? any ideas? thanks.It's hard to know specifically what is broken without seeing code or error messages. My guess is that the variable Frame1 is not in scope in the dialog box code. But I would suggest a different approach...- Make the dialog box code independent of the values of variables in Frame1. Generally for me this means packaging up the dialog box in a function or class that is passed the values it needs to use and returns some result to the user. A very simple example is a dialog box that presents an error message; you could make a function showError(msg) that doesn't know anything about its caller.- In the event handler for the button in Frame1, gather the values needed by the dialog, launch it, get the result and handle it.This style keeps your dialog code independent of the rest of the pro! gram. An immediate benefit is that you can write a simple test driver that exercises the dialog without having to create any infrastructure. (This is the way I create most dialog boxes. I run it standalone until I am happy with its appearance and function, then I integrate it into the rest of the app.) Another long-term benefit is the dialogs are reusable; you may not see a need for this but in the long run some of them will probably have more than one use.HTH,Kent___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] passing variables between frames?
actually I got it to work! thanks for the help. JeffKent Johnson <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:> ok, thanks. that makes sense; however I do not know how to pass a > variable from my parent frame to the dialog. I have tried this before > unsuccessfully. could you provide a quick example of how to pass a > variable to a dialog from a frame. I am not sure how this works. thanksCan you post your (maybe broken) dialog code with a placeholder for the variable you want?Kent___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] wxpython button icons?
Hello, does anyone know if there is a list of widows icons available? I'm creating an application for windows and I'd like to use standard icons for things like a "print" button or "save" button etc. thanks. Jeff ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] IDLE not working?
Hello, I upgraded python to 2.4 and now my IDLE isn't working. There is an error indicating something is wrong with my configuration file for the IDLE settings. Any suggestions for how to solve this problem would be much appreciated. thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] imbedding python into another program?
hello, is it possible to add something like the python IDLE into another program, say if I wanted to simply run scripts from within a wxPython program? Could someone point me to the correct reference? thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] imbedding python into another program?
ok, thanks! that helps. I have an application that reads a data file, crunches some numbers, and spits out some graphs. In addition to this I would also like users to be able to write small python scripts to operate on the data that is available within the program. I suppose this could be accomplished by simply reading a text input and sending off the command to the command module and then returning the result to the user?? Is this feasible? thanks for the help! JeffDanny Yoo <[EMAIL PROTECTED]> wrote: On Wed, 1 Jun 2005, Jeff Peery wrote:> hello, is it possible to add something like the python IDLE into another> programHi Jeff,Getting IDLE to work within wxPython is technically possible, but probablya little tricky, since it'll involve getting the GUI event loops tocooperate.I believe it is doable --- there's code in the Twisted Python project, forexample, that allows the Tkinter event loop to integrate into Twisted'sevent loop. That being said, this might be overkill for what you'retrying to do.> say if I wanted to simply run scripts from within a wxPython program?> Could someone point me to the correct reference? thanks.Hmmm... do you necessarily have to have those scripts run through IDLEthen? What kind of scripts are you trying to run through wxPython?Would s! omething like the 'commands' module be useful for you?http://www.python.org/doc/lib/module-commands.htmlBest of wishes to you!___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] resizing an array of strings?
Hello, I'm having a bit of trouble resizing/reshaping an array of strings. here's what I'm trying to do: myString = ['hi','my','name','is','Jeff'] reshape(myString, (2,2)) What I get from this is something like: [['h','i'], ['m','y']] What I want is: [['hi','my'], ['name','is']] How might this work best?___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] fourier transform
Hello, I have a signal that I want to do a fourier transform on. I tried using FFT.fft(data).real but I don't understand the output. what is output from this function, and why doesn't it require amplitude and time as inputs? thanks.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] fourier transform
thanks for the help. I think I'm understanding this a bit better. although I still don't completely understand the output. here is an example... for the input I have 1024 samples taken from a 1 Hz square wave with amplitude = 1. for the output I would expect an infinite number of frequencies. the output from FFT.fft(myData).real is this: . . . -0.498 10.0 2-0.498 30.0 4-0.498 50.0 6-0.498 70.0 8-0.498 90.0 10-0.498 110.0 12-0.498 130.0 14-0.498 150.0 16-0.498 17 . .. I'm not sure why the output alternates from 0 and 0.498. I would expect 0.498 at all frequencies? why the oscillation? Christian Meesters <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:>> Hello, I have a signal that I want to do a fourier transform on. I > tried using FFT.fft(data).real but I don't understand the output. > what is output from this function, and why doesn't it require > amplitude and time as inputs?Hi Jeff,As Danny wrote, your input are real numbers and your output will be complex numbers. I don't want to point you to the numarray documentation once more, but you might to check out this: http://mathworld.wolfram.com/FourierSeries.html as for why you get complex numbers back. (To get only the real value part try real_fft() in numarrayl.)In general in numerical computation your input is simply a series of real numbers - of equal spacing in the dimension you want to consider. Which dimension you choose (amplitudes and time/phase or amplitudes and spacial frequencies and so on) is up to you. It depends on your physical or mathematical question. IMHO the best introduction you can get on Fourier Transforms & programming can be found in Numerical Recipies (here the "Numerical Recipies in C"-link http://www.library.cornell.edu/nr/bookcpdf.html - check chapter 12).Have fun with FFTs!CheersChristian___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] fourier transform
ok, this makes more sense. what I want to know is the amplitude for the output frequencies. I'm using import FFT, and FFT.fft(). the first element of the output is the DC constant? not sure what this is. is the amplitude for all other elements plus the DC equal to the actual amplitude? thanks.Pawel Kraszewski <[EMAIL PROTECTED]> wrote: > Hello, I have a signal that I want to do a fourier transform on. I tried> using FFT.fft(data).real but I don't understand the output. what is output> from this function, and why doesn't it require amplitude and time as> inputs?Please write the package you use for FFT. Standard Python doesn't have one. Perhaps you use some custom Python? Like Enthought Python? If so, the exhaustive guide is delivered with it in CHM (windows help) format.1. In general FFT algorithms require you to supply just N complex values (complex contains both amplitude and phase of signal). If you supply real values, the system assumes phase=0 for each sample and takes given value for amplitude.2. You DO supply a time information, you just didn't think of it this way: each consecutive sample is taken one fixed clock tick later, so p! osition of sample in data gives you the time it was taken.3. Results of FFT are in the form of complex vector of the same length as data. Starting from position 0 it gives you an constant (DC factor), position 1 an amplitude and phase (remember - complex number gives you both amplitude and phase) of wave of the length table/2 and so on. If you take real value of this, you discard part of the information. AFAIR - taking real part gives you sine component, taking imaginary part gives you cosine component, taking absolute value gives you total amplitude and taking angle gives you phase.4. The answer is symmetrical - usually you take only half of it. I don't remember the exact difference between the halves, but you may find it in any article on FFT.Best regards,Pawel Kraszewski___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] fourier transform
ok, this makes more sense. what I want to know is the amplitude for the output frequencies. I'm using import FFT, and FFT.fft(). the first element of the output is the DC constant? not sure what this is. is the amplitude for all other elements plus the DC equal to the actual amplitude? thanks.Pawel Kraszewski <[EMAIL PROTECTED]> wrote: > Hello, I have a signal that I want to do a fourier transform on. I tried> using FFT.fft(data).real but I don't understand the output. what is output> from this function, and why doesn't it require amplitude and time as> inputs?Please write the package you use for FFT. Standard Python doesn't have one. Perhaps you use some custom Python? Like Enthought Python? If so, the exhaustive guide is delivered with it in CHM (windows help) format.1. In general FFT algorithms require you to supply just N complex values (complex contains both amplitude and phase of signal). If you supply real values, the system assumes phase=0 for each sample and takes given value for amplitude.2. You DO supply a time information, you just didn't think of it this way: each consecutive sample is taken one fixed clock tick later, so p! osition of sample in data gives you the time it was taken.3. Results of FFT are in the form of complex vector of the same length as data. Starting from position 0 it gives you an constant (DC factor), position 1 an amplitude and phase (remember - complex number gives you both amplitude and phase) of wave of the length table/2 and so on. If you take real value of this, you discard part of the information. AFAIR - taking real part gives you sine component, taking imaginary part gives you cosine component, taking absolute value gives you total amplitude and taking angle gives you phase.4. The answer is symmetrical - usually you take only half of it. I don't remember the exact difference between the halves, but you may find it in any article on FFT.Best regards,Pawel Kraszewski___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] fourier transform
Hi Christian,
sorry for the lack of detail. how about I use a sine wave because I know what the output should look like - amplitude of one at frequency equal to the frequency of the sine wave.
one period of a sin wave that cycles at one hertz:
period = 1
input = sin(arange(0,64)*3.14159*2/64.0)
do the fft:myFFT = FFT.real_fft(myData)
the change in time between elements is:
delta_time = period/64
inverse of time is the frequency:
delta_freq = 1/delta_time
print the results:
for i in range(1,len(myFFT)): print myFFT[i], delta_freq*i
hope this is more clear. from the output I would expect that two spikes appear with amplitude = 1. one spike is the positive frequency (first half of the fft) and another spike is the negative frequency (second half), the first half and second half are symmetrical about the midpoint of the fft. but this is what I get:
-8.22612478587e-005 64.02.65354186171e-006 128.02.65357174311e-006 192.02.65358011376e-006 256.02.65358370024e-006 320.02.65358557785e-006 384.02.65358668451e-006 448.02.65358739808e-006 512.02.65358788076e-006 576.02.65358822231e-006 640.0
.
.
.
I don't understand the output amplitudes. they should all be zero except for at one herz it should be one. not sure about the frequency for that matter either. I gotta dig up my math book and figure this out. in the meantime any suggestions for what this is outputing would be greatly appreciated! thanks.
Jeff
Christian Meesters <[EMAIL PROTECTED]> wrote:
HiPawel Kraszewski wrote:> 4. The answer is symmetrical - usually you take only half of it. I > don't> remember the exact difference between the halves, but you may find it > in any> article on FFT.The real part is identical the imaginary part has the opposite sign ("same amplitude, opposite phase").Jeff Peery wrote:> thanks for the help. I think I'm understanding this a bit better. > although I still don't completely understand the output. here is an > example... for the input I have 1024 samples taken from a 1 Hz square > wave with amplitude = 1. for the output I would expect an infinite > number of frequencies. the output from FFT.fft(myData).real is this:>> .> .> .> -0.498 1> 0.0 2> -0.498 3> 0.0 4> -0.498 5&g!
t; 0.0
6> -0.498 7> 0.0 8Frankly, I don't understand this. After your description I thought your input is like "array([0, 1, 0, ..., 1, 0, 1])". But this can't be. Could you show us how exactly your input array looks like?And how do we have to read your output? Is this a 1d-array? What do the two numbers per line mean?CheersChristianPS Sorry for the late reply.___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___
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Re: [Tutor] fourier transform
Hi again, is there a good reason why the output is dependant upon the sampling rate. in the example if you increase from say 64 to 128 samples the output increases by a factor of 2. Christian Meesters <[EMAIL PROTECTED]> wrote: Hi Jeff,On 3 Aug 2005, at 02:03, Jeff Peery wrote:> hope this is more clear. from the output I would expect that two > spikes appear with amplitude = 1. [snip]> I don't understand the output amplitudes. they should all be zero > except for at one herz it should be one. not sure about the frequency > for that matter either. I gotta dig up my math book and figure this > out. in the meantime any suggestions for what this is outputing would > be greatly appreciated! thanks.> Yes, well, the math book idea might be a good one ;-). No, but seriously: You are just making a little mistake. First of all you are NOT exactly calculating a Fourier transform but a numerical estimation of it (you are dealing with an array of discrete data points, which is unavoidable when dealing with comp! uters ;-)). Look on your sine wave. Is it a perfect one? Then, what do you see when you plot your data? Some 'noise' and one little peak. The noise is due to errors which have to do with floating point arithmetics (see http://docs.python.org/tut/node16.html). It's really small and in most cases I'm sure it's neglectable as well.But when looking on your idea of what you would expect, I'm wondering whether you actually want a power spectrum estimation (see http://mathworld.wolfram.com/PowerSpectrum.html)? TrymyFFT = abs(fft.fft(inp))instead ofmyFFT = fft.real_fft(inp)This a least might come close to what I think you want to see, right?You might have a look onmyFFt = fft.fft(inp).realas well, because it might make things to appear a little clearer.One more remark: Try to avoid overwriting python key words like 'input'.Hope this helped.CheersChristianPS Here is ! the code I used. It looks a bit different from yours - I hope the comments help a bit:from numarray import *import numarray.fft as fft#at least one of the numbers should be floating point hereperiod = 1.0#use numarray's / Numpy's pi instead of 3.14...inp = sin(arange(0,64)*pi*2/64.0)myFFT = abs(fft.fft(inp))#or#myFFt = fft.fft(inp).real#or#myFFT = fft.real_fft(inp)#depending on what you really wantdtime = period/64.0dfreq = 1.0/dtimefor i in range(len(myFFT)):print myFFT[i], dfreq*i___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] imbedding python into another program?
Andre, thanks for the help with this. I put it to work yesterday and it works perfectly. was wondering if it is possible to import modules without a users having to type 'import whatever'. for example in my application I would like the user to just start operating on arrays that exist in my program. But I have to load both the arrays and Numeric into the python shell that I created. how can I do this? thanks.André Roberge <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:> hello, is it possible to add something like the python IDLE into> another program, say if I wanted to simply run scripts from within a> wxPython program? Could someone point me to the correct reference?> thanks.> Hi Jeff,you may want to have a look at PyCrust, PyShell and the like.I do something like this in my rur-ple app (on sourceforge).The relevant lines of code are:import wx.py as py[inside a wx.Notebook]win = py.shell.Shell(self.window, -1,introText = tr.INTERPRETER_INTRO_TEXT)self.window.AddPage(win, tr.PYTHON_INTERPRETER)HTH,André___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] commercial use of python?
hello, I was wondering about the license agreement for python. if I use python to create an application that is intended to sell commercially for profit is that violating the agreement listed in www.opensource.com? Or is that only for the interpreter? for example if I embed the python interpreter into a application written in pthon that is intended to be sold for profit is that violating the license agreement? thanks.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] fftpack
Hello, does anyone know how to open the fft function? I want to view it in the IDLE although the only file i have is the fftpack.pyd which I beleive is a compiled file and it looks like mush. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] fyi - re: fft
hello, thought I'd post my progress with fiddling with the FFT. import FFT I've been using fft by taking the real part with: myFFT = abs(FFT.fft()) the returned values are the fourier coefficients starting with a0 the old thing is that the output is symmetrical about N/2 where n>N/2 is the negative frequencies. also all outputs are multiplied by N, so to get anything meaningful (at least in my case) you must divide the output by N. so to get a0 you want myFFT[0]/float(N). I compared several inputs with the output and I also used the output to calculate the fourier series and it all looks like it should. thanks for those that had input. Jeff thats all I got.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] whats the best way to structure my data?
hello, I was wondering what might be the best way to structure my data within python. I am sampling data points, and in each there is a time, value, and text string associated with that sample. so I was thinking I'd make a list of 'measurement objects' and each object would have the attributes: time, value, and text... but I want to operate on the numerical values to find the average and stdev... so I'm not sure how to operate on my data if it is inside an object. right now I have three arrays, a date array, a value array, and a text array. so I can operate on each array without trouble. but it'd be cleaner in my code and easier to deal with if I had a list of these measurement objects. for example: # a class for my measurements class measurement: def __init__(self): self.text = '' self.value=0 self.time=datetime.today() # I start with an empty list measurements = [] # as I collect data in my code I append an object to the list measurements.append(sample) measurements[-1].value = value measurements[-1].text = text measurements[-1].time = time # now I don't know what to do here. I want the mean of all my data # but I need a list or array to operate on but instead my data is inside each object # I don't really want to make a temporary array, is there a way to operate on the # data in all my objects as if it were an array or list? mean = numpy.mean() is there a way to operate on the data when it is structured like this? thanks. Jeff - Ahhh...imagining that irresistible "new car" smell? Check outnew cars at Yahoo! Autos.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] whats the best way to structure my data?
ok, thanks. so is there a difference in performance if I do it this way versus if I use say a numpy function on an array? thanks. Jeff John Fouhy <[EMAIL PROTECTED]> wrote: On 11/05/07, Jeff Peery wrote: > hello, I was wondering what might be the best way to structure my data > within python. I am sampling data points, and in each there is a time, > value, and text string associated with that sample. so I was thinking I'd > make a list of 'measurement objects' and each object would have the > attributes: time, value, and text... but I want to operate on the numerical > values to find the average and stdev... so I'm not sure how to operate on my > data if it is inside an object. [...] > mean = numpy.mean() > > is there a way to operate on the data when it is structured like this? You could use a list comprehension or a generator expression. eg: mean = sum(m.value for m in measurements)/len(measurements) Also, here is an alternative way you could store your data: as a list of tuples. You could write code like: # measurements is a list of tuples. Each element is a triple (value, text, time). measurements = [] Then, later on, when you get a new measurement, something like: measurements.append((value, text, time)) You can find the mean in the same way: mean = sum(m[0] for m in measurements)/len(measurement) -- John. - Ahhh...imagining that irresistible "new car" smell? Check outnew cars at Yahoo! Autos.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] locking files
does anyone know if there is a way in python to lock a file so others cannot open it, or can only read it? I have a program that read/writes to a file and I would like to lock others out of it while I'm operating on it. thanks. Jeff - We won't tell. Get more on shows you hate to love (and love to hate): Yahoo! TV's Guilty Pleasures list.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] performance
Hello, I've got a quick question regarding performance of lists. I am taking measurements and building up a list of objects for each measurement. the class I created for the objects has attributes of time, numerical value, person's name who collected the sample etc. I also have functions within my class (I think they are properly named 'accessors'?) that get a piece of data within the object, for example 'self.GetSampleTime()'. I'm wondering what happens to my performance as I add more accesors to my class. How are the accesors managed? will each object in my list of objects contain the data for each accesor or do all the objects look to the sample module for the accesor? will my list of objects become huge and slow as I add more accessors? thanks. Jeff - Don't let your dream ride pass you by.Make it a reality with Yahoo! Autos. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] pickle question
hello, I have a question about the pickler. I'm using it to save objects in a program of mine that I can later reload to use. I was wondering how the pickle works and how it references the class module when I unpickle the pickled objects. for example I save some objects using the pickler, then I continue to develop my program so the class module is changed and additional attributes and methods are added. What happens now when I unpickle the pickled data and try to operate on it using the new methods and new attributes? here's an example if I didn't explain myself well... I create a class of data called 'var' class var: def __init__(self): self.data = numpy.array([1,2,3,4]) self.color = 'blue' def operate(self): return self.data+1 now create the instance: myVariable = var() I then pickle it to some file. and now I continue to develop my class module: class var: def __init__(self): self.data = numpy.array([1,2,3,4]) self.color = 'blue' self.name = 'bob' def operate(self): return self.data+1 def GetName(self): return self.name So now I unpickle my object from before using my new program. and I use MyVar.GetName(). does this work? If not, how do people usually handle this type of problem? or do they not use the pickler to save program data? big thanks! Jeff - Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] setstate trouble when unpickling
Hello, I've got a fairly simple class instance that I'm pickling. I'm using setstate to update the instance when I unpickle. Although the setstate doesn't seem to be called upon unpickling... here's an example, if anyone see's what I'm doing wrong, please let me know. Thanks! so I say start out with this class: class dog: def __init__(self): self.num_legs = 4 then I pickle the instance of: sparky = dog() then I update my dog class to: class dog: def __init__(self): self.hair_color = 'brown' self.num_legs = 4 def __setstate__(self, d): if 'hair_color' not in d: d['hair_color'] = 'brown' self.__dict__.update(d) print 'did this work?' Now when I unpickle the original pickled object sparky I would hope to see 'did this work' and I would also hope that sparky would have updated to have the attribute 'hair_color' but nothing of the sort happens. if just unpickles sparky without updating the attributes as I was hoping. Thanks! Jeff - Never miss a thing. Make Yahoo your homepage.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] distutils?
Hello, I was wondering what is the difference between the distutils core and py2exe... they look the same to me? thanks.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] changes made if IDLE not updating when application executed?
Hello, I am running a script I wrote with IDLE. if I edit the script them hit 'F5' to run it again, it seems to run the old script prior to the last save. I have to close down the IDLE then start it again and hit 'F5' to get the changes to execute. is there a way to fix this? Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] reading excel and access files
hello, can python read excel and access files? If so where do I go to read about how this would work? thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] reading excel and access files
Great, this is lots of good info. thanks everyone for your input! JeffKent Johnson <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:> hello, can python read excel and access files? If so where do I go to > read about how this would work? thanks.There are some resources here that might be helpful:http://www.python.org/pypi?%3Aaction=search&name=&version=&summary=&description=&keywords=excel&_pypi_hidden=0Kent___Tutor maillist - Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] installation programs
Hello, I want to create an installation program. Can anyone tell me what the best program would be to use... maybe inno setup or install shield? do these work with python programs? do they require programming in another language? thanks. Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] hiding a notebook page
hello, I'm using wxpython to write a windows app. I want to be able to hide a page in a notebook and I'm not sure how to do it. functionally its the same as doing: notebook.Show(False) but I want that to work for just one notebook page and not the whole notebook. I tried the wxpython list but didn't have much luck. any help would be much appreciated. thanks! Jeff___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] (no subject)
hello, I am trying to find the source code for FFT. I found the FFT.py module athough I cannot find the actual code that runs the FFT. Is it in a compiled form or can I view its source? thanks.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] comiling python to microchip?
is it possible to take python code and compile it for use in a microprocessor?___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] (no subject)
Yahoo! FareChase - Search multiple travel sites in one click. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] (no subject)
Yahoo! FareChase - Search multiple travel sites in one click. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] numeric typeError
hello, I'm getting this strange error: myArray1[1:2] = myArray2[3:4] TypeError: Array can not be safely cast to required type everytime I try to copy a slice from one array to the next this error occurs. the slices are the same size and I initialized the arrays using Numeric.zeros(10, 'Float'). anyone have an idea why this happens? thanks. Jeff Yahoo! FareChase - Search multiple travel sites in one click. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] PLC communication with python?
Hello, I would like to write a python script that communicates with a PLC (programmable logic controller) as well as instruments like calipers and things. I'm completely in the dark here and not sure where to start reading and learning. could someone point me in the right direction for learning this stuff? thanks!Jeff Yahoo! Mail Bring photos to life! New PhotoMail makes sharing a breeze. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] numpy speed problems
hello, I am having some trouble with the speed of numpy. I'm crunching some numbers (see the attached script) and in total I have 1,000,000 grid points over which I am integrating. I'm doing a bunch of adding, mulitply, divide, powers, etc, but in total there are 1,000,000 points to do these operations over and it really shouldn't take this long... as far as I know. my last simulation took about 8+ hours.What might I be doing wrong in my code to cause this to be so slow? big thanks!!Jeff __Do You Yahoo!?Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com from numpy import *
"""
function definitions
"""
def GetPressure(x_coord, y_coord, x_r, y_r, z_r, dx, dy, w_mn, rho, v_mn, k_mn,
n, m):
# intialize pressure
p = 0.0 + 1j
# sum contributions from all point sources to receiver
for ii in range(n):
for jj in range(m):
r = ((x_r - x_coord[ii])**2.0 + (y_r - y_coord[jj])**2.0 + (z_r
- 0.0)**2)**0.5
p += (1j*w_mn*rho*v_mn[ii][jj])*exp(1j*k_mn*r)*dx*dy/(2.0*pi*r)
p = sqrt(p*conjugate(p))
return abs(p)
"""
vaiables and constants
"""
"""problem definition parameter"""
n = arange(1,70) #mode number in x direction
m = arange(1,70) #mode number in y direction
mode_n = 10 #mode number - 1
mode_m = 10 #mode number - 1
L = 1.2 #piston length(m)
W = 0.6 #piston width(m)
"""material properties fluid"""
c = 343.0 #speed sound in water (m/s)
rho_a = 1.21 #density of air (kg/m^3)
"""piston material properties"""
E = 7.0e10#youngs modulus (N/m^2) (stainless
steel)
nu = 0.29 #poisson's ratio (stainless steel
rho = 2700.0#density of piston (stainless steel)
(kg/m^3)
t = 0.0015#piston thickness (m)
"""wave speed, wave number, frequency"""
c_l = (E/(rho*(1 - nu**2)))**0.5#longitudinal wave speed in
piston
k_x = n*pi/W#wave number x direction
k_y = m*pi/L#wave number y direction
k_mn= (k_x[mode_n]**2 + k_y[mode_m]**2)**0.5#bending wave number for n
and m mode
w_c = (c**2)/(1.8*c_l*t)#critical frequency (Hz)
w_mn= (k_mn**2)*1.8*c_l*t/(2.0*pi)**2 #frequency for n and m (see
notes 5/15/06)
k_c = 2.0*pi*(w_c/(1.8*c_l*t))**0.5 #critical wave number
k_a = 2.0*pi*w_mn/c#wave number in
acoustic medium (air)
"""piston grid"""
dx = 1.0/k_a #x direction step in space (m)
dy = 1.0/k_a #y direction step in space (m)
if dx < 0.005:
dx = 0.005
dy = 0.005
num_y = int(L/dy) #number of nodes in y direction
num_x = int(W/dx) #number of nodes in x direction
#piston grid coordinates
x_coord = arange(num_x, dtype=float)*W/num_x - W/2.0
y_coord = arange(num_y, dtype=float)*L/num_y - L/2.0
"""field grid"""
a = 1
b = 50
d = 50
x_r = arange(a, dtype=float)*1.0/float(a) #x position of receiver (m)
y_r = arange(b, dtype=float)*1.0/float(b) #y position of receiver (m)
z_r = arange(d, dtype=float)*10.0/float(d)#z position of receiver (m)
"""acoustic variables"""
p = 0 #amplitude of pressure at receiver
(Pa)
r = 0 #distance from origin to receiver(m)
p_field = zeros((a,b,d), dtype=float) #pressure field (m)
"""calculate piston surface velocity amplitude"""
U_mn= zeros((len(x_coord), len(y_coord)), dtype=float)
for i in range(len(x_coord)):
for j in range(len(y_coord)):
#amplitude of piston surface displacement
U_mn[i][j] =
sin(n[mode_n]*pi*(L/2.0+x_coord[i]))*sin(m[mode_m]*pi*(W/2.0+y_coord[j]))
#amplitude of piston surface velocity(m/s)
V_mn = w_mn*U_mn
"""
numerical integration of Raleigh's equation
"""
for i in range(a):
for j in range(b):
for k in range(d):
p_field[i][j][k] = GetPressure(x_coord, y_coord, x_r[i], y_r[j],
z_r[k], dx, dy, w_mn, rho, V_mn, k_mn, num_x, num_y)
print '%d Percent Complete'%(100.0*j/b)
p_field = 20.0*log10(p_field)
fileHandle = file('beam pattern.dat', "w")
fileHandle.write('TITLE = "HW 4"\n')
fileHandle.write('VARIABLES = "x"\n"y"\n"z"\n"pressure"\n')
fileHandle.write('ZONE T="%s"\n' % 'pressure field')
fileHandle.write('I=%d, J=1, ZONETYPE=Ordered\n' % (a*b*d))
fileHandle.write('DATAPACKING=POINT DT=(DOUBLE DOUBLE DOUBLE DOUBLE)\n')
for ii in range(a):
for jj in range(b):
for kk in range(d):
fileHandle.write('%f %f %f %f\n' % (x_r[ii], y_r[jj], z_r[kk],
p_field[ii
[Tutor] treelistctrl help!
hello, I'm having some trouble with treelistctrl in wx python and I was wondering if there is someone who would share their code as an example. thanks!Jeff Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail Beta.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] modbus communication with python?
Hello, I need to talk read write to a modbus so that I can work with a PLC. I have not a clue how this all works. does python have a modbus module or where might I look to find how to do this? thanks.Jeff Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail Beta.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] modbus communication with python?
Hello, I need to talk read write to a modbus so that I can work with a PLC. I have not a clue how this all works. does python have a modbus module or where might I look to find how to do this? thanks.Jeff How low will we go? Check out Yahoo! Messengers low PC-to-Phone call rates.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] how to post an event?
Hello, I am having a bit of trouble figuring out how to post an event. I attached my sample program. I assigned a button event to each button in the program. I want to post an event when the second button is pressed that executes the first button. thanks.Jeff
Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min.#!/usr/bin/env python
#Boa:App:BoaApp
import wx
import Frame1
modules ={'Frame1': [1, 'Main frame of Application', 'Frame1.py']}
class BoaApp(wx.App):
def OnInit(self):
wx.InitAllImageHandlers()
self.main = Frame1.create(None)
self.main.Show()
self.SetTopWindow(self.main)
return True
def main():
application = BoaApp(0)
application.MainLoop()
if __name__ == '__main__':
main()
#Boa:Frame:Frame1
import wx
def create(parent):
return Frame1(parent)
[wxID_FRAME1, wxID_FRAME1BUTTON1, wxID_FRAME1BUTTON2,
] = [wx.NewId() for _init_ctrls in range(3)]
class Frame1(wx.Frame):
def _init_coll_boxSizer1_Items(self, parent):
# generated method, don't edit
parent.AddWindow(self.button2, 1, border=10, flag=wx.ALL | wx.GROW)
parent.AddWindow(self.button1, 1, border=10, flag=wx.ALL | wx.GROW)
def _init_sizers(self):
# generated method, don't edit
self.boxSizer1 = wx.BoxSizer(orient=wx.VERTICAL)
self._init_coll_boxSizer1_Items(self.boxSizer1)
self.SetSizer(self.boxSizer1)
def _init_ctrls(self, prnt):
# generated method, don't edit
wx.Frame.__init__(self, id=wxID_FRAME1, name='', parent=prnt,
pos=wx.Point(467, 234), size=wx.Size(324, 386),
style=wx.DEFAULT_FRAME_STYLE, title='Frame1')
self.SetClientSize(wx.Size(316, 359))
self.button1 = wx.Button(id=wxID_FRAME1BUTTON1, label='button1',
name='button1', parent=self, pos=wx.Point(10, 189),
size=wx.Size(296, 159), style=0)
self.button1.Bind(wx.EVT_BUTTON, self.OnButton1Button,
id=wxID_FRAME1BUTTON1)
self.button2 = wx.Button(id=wxID_FRAME1BUTTON2, label='button2',
name='button2', parent=self, pos=wx.Point(10, 10),
size=wx.Size(296, 159), style=0)
self.button2.Bind(wx.EVT_BUTTON, self.OnButton2Button,
id=wxID_FRAME1BUTTON2)
self._init_sizers()
def __init__(self, parent):
self._init_ctrls(parent)
def OnButton1Button(self, event):
print 'hello'
def OnButton2Button(self, event):
event.Skip()
"""what do I do here to post an event that executes 'OnButton1Button()'
?"""
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Re: [Tutor] how to post an event?
Ah, yes it works, thanks. I had previously tried to simply call the function (OnButton1Button() from OnButton2Button()) instead of posting an event but I guess I did this wrong and abandoned the effort assuming that it wouldn't work. Anyhow, I got it working now, thanks again!JeffAlan Gauld <[EMAIL PROTECTED]> wrote: > Hello, I am having a bit of trouble figuring out how to post an > event.Do you really need to post an event?>self.button2.Bind(wx.EVT_BUTTON, self.OnButton2Button,> id=wxID_FRAME1BUTTON2)could you just bi8nd the same method to both buttons?>def OnButton1Button(self, event):>print 'hello'>>def OnButton2Button(self, event):>event.Skip()>"""what do I do here to post an event that executes > 'OnButton1Button()' ?"""Or could you call OnButton1Button(self,event) directly?Does it have to involve an event being posted to the Q - sometimesneeded I know but not often...Alan G.> Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] modbus communication with python?
okay, yes thank you! I have seen this, although I looked a the code and it appears that this is actually a modbus server (please correct me if I am wrong, I am really new to modbus and PLC's). We are already using a modbus server (KEPDirect for PLC's, automation direct) and I beleive we are using a Koyo PLC. but I simply want to read and write values stored on the modbus server, I don't actually want to create a new server. I'm not sure that this module is the way to go (although again I might be wrong), what might be my other options and where should I go to learn about this? thanks!JeffJason Massey <[EMAIL PROTECTED]> wrote: Googling for modbus python turned up:https://lintouch.org/repos/lintouch/lsp-modbus/trunk/tests/ On 7/5/06, Jeff Peery <[EMAIL PROTECTED]> wrote: Hello, I need to talk read write to a modbus so that I can work with a PLC. I have not a clue how this all works. does python have a modbus module or where might I look to find how to do this? thanks. JeffHow low will we go? Check out Yahoo! Messenger's low PC-to-Phone call rates. ___Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] python processing of web html forms
Hello, I want to use python to process information input into a HTML form on my website. how is this typically performed? I saw cherrypy and also quixote for web python stuff... I have no experience with python on the web. Thanks.jeff Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] threading
hello, how do I stop a thread? do I need to kill it or can I simply call a stop function... kinda like the start function? I read a bit on google and it sounded like using a kill isn't recommended for some reason... so how is this thing stopped? thanks!Jeff Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] threading
h, ok, well that is what I am currently doing but something is causing it to continue... guess I have some digging around to do. thanks for the help!JeffJohn Fouhy <[EMAIL PROTECTED]> wrote: On 16/08/06, Jeff Peery <[EMAIL PROTECTED]> wrote:> hello, how do I stop a thread? do I need to kill it or can I simply call a> stop function... kinda like the start function? I read a bit on google and> it sounded like using a kill isn't recommended for some reason... so how is> this thing stopped? thanks!The only good way for a thread to stop is for its run() method to exit.It kinda depends what your thread is doing, and what technique you areusing to keep it alive, but one possibility is to do something like:class Worker(threading.Thread):def run(self): self.running = Truewhile(self.running):# do stuffdef stop(self):self.running = FalseIn this case, the you call .stop() on your Worker object, and thethread will exit when it next gets to the top of the while loop.-- John. Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] how do I find where my program is installed?
hello, I created an executable using py2exe and innosetup for windows. I need to figure out where the user has installed my program so that I can direct the program to the installation files that it needs to run. I ran into this problem because I have a file type that my program reads and I have registered this type in the windows registry so that when this file type is double clicked my application is launched. when this happens my program thinks the working directory is the directory where that registered file was located... not the installation directory where it should be working in needless to say that lots of things go wrong when my program is launched this way. so I need to tell my program to set the working directory back to the installation directory... but where is this?thanks!Jeff Stay in the know. Pulse on the new Yahoo.com. Check it out. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] how do I find where my program is installed?
Thanks Bill, I read the link you sent, and I am not sure what they mean by "You cannot rely on __file__, because __file__ is not there in the py2exed main-script." can't I use _file_ in my application though? This is what I just added to my application and it seems to do the trick... is there an exception that I am not aware of?using your method, what do you do with 'installDir' in py2exe?thanks for the help. [EMAIL PROTECTED] wrote: > way. so I need to tell my program to set the working directory back to the> installation directory... but where is this?>Here's what I do in my py2exe app:installDir = os.path.dirname(os.path.abspath(sys.argv[0]))and take a look at this link:http://www.py2exe.org/index.cgi/WhereAmIHTH,Bill Do you Yahoo!? Get on board. You're invited to try the new Yahoo! Mail.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] python shell not working like it used to
hello, I just upgraded to python 2.5 and wxpython 2.6. I'm not sure the correct
list for this but I'm trying to shove some variables into a py shell using the
below code. this worked pretty well before, but now it gives me an error on the
last line of my brief example. The error is:
'dict' object has no attribute 'this'
it occurs on line 171 in shell.py. so I looked in shell.py and it looks like
this:
def __init__(self, other):
"""Create a ShellFacade instance."""
d = self.__dict__
d['other'] = other
d['helpText'] = HELP_TEXT
d['this'] = other.this
"other" here is the dictionary I pass in (I think), so it's for some reason
looking for some attribute in my dictionary called 'this'. of course my
dictionary doesn't have this attribute. I have no idea what this is. any ideas?
my few lines of code are below.
import py
import wx.py as py
partList = {'this is some dictionary':1}
pyWindow2 = py.editor.EditWindow(py.editor.Editor, splitterWindow1,
-1)
pyWindow1 = py.shell.Shell(splitterWindow1, -1, introText = None)
pyWindow1.interp.locals['partList'] = py.shell.ShellFacade(partList)
-
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Re: [Tutor] python shell not working like it used to
well the __init__() funciton is not my code, it is in: C:\Python24\Lib\site-packages\wx-2.6-msw-unicode\wx\py\shell.py as I mentioned I upgraded wxpython... maybe I should email there... anyhow I just want to use my dictionary in the shell, but I'm not sure what the attribute 'this' is... it seems to be something different from my previous version of wxpython. thanks. J Alan Gauld <[EMAIL PROTECTED]> wrote: "Jeff Peery" wrote > def __init__(self, other): >d['this'] = other.this > > "other" here is the dictionary I pass in (I think), > so it's for some reason looking for some attribute in > my dictionary called 'this'. other is whatever you pass in. The code expects it to be dictionary like and to have a this attribute > of course my dictionary doesn't have this attribute. So why is your code trying to access one if you know it doesn't exist? And why are you surprised at the error message? (Or is the init() not your code?) > I have no idea what this is. any ideas? Youu seem to have answered your own question. You are passing a dictionary into init() that does not have a this attribute but the code inside the init() is trying to access a this attribute. It can't find one so it raises an error. Either remove the this access in init or add a thus attribute to your dictionary argument. Or pass an argument that does have a this attribute. I'm slightly confused about what you are asking us to tell you? HTH, -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor - Everyone is raving about the all-new Yahoo! Mail beta.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] recommendation for good OO book?
Hello, I've been using python for a few years now and I really like it. Although i am beginning to realize I really don't utilize this object oriented stuff in a good way. Does anyone have a favorite book regarding the basics/intro to object oriented programming, how to write good OO code?? thanks, Jeff - Don't get soaked. Take a quick peek at the forecast with theYahoo! Search weather shortcut.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] sorting data from multiple arrays
hello, I typically run into this problem and I'm not always sure of the most efficient way to handle it. I often work with multiple arrays of data, say arrays a, b, and c, and I want to sort the elements of b and c based on a. for example: a = [3,2,1,4] b = ['hi', 'my','name', 'is'] c = [5,2,4,2] I order 'a' from small to large and do the same rearrangement to 'b' and 'c': a = [1,2,3,4] b = ['name', 'my','hi', 'is'] c = [4,2,5,2] usually I do some terrible looking for loops and iterate over the whole mess is there a clean, efficient way to do this, or is there a nice function that would reorder the elements of b and c based on the soring of a? thanks - Don't be flakey. Get Yahoo! Mail for Mobile and always stay connected to friends.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sorting data from multiple arrays
Thanks for all the responses, that is a huge help!
Jeff
Kent Johnson <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:
> hello, I typically run into this problem and I'm not always sure of the
> most efficient way to handle it. I often work with multiple arrays of
> data, say arrays a, b, and c, and I want to sort the elements of b and c
> based on a. for example:
>
> a = [3,2,1,4]
> b = ['hi', 'my','name', 'is']
> c = [5,2,4,2]
>
> I order 'a' from small to large and do the same rearrangement to 'b' and
> 'c':
> a = [1,2,3,4]
> b = ['name', 'my','hi', 'is']
> c = [4,2,5,2]
>
> usually I do some terrible looking for loops and iterate over the whole
> mess is there a clean, efficient way to do this, or is there a nice
> function that would reorder the elements of b and c based on the soring
> of a?
Decorate-sort-undecorate
(http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52234)
to the rescue:
In [12]: a = [3,2,1,4]
In [13]: b = ['hi', 'my','name', 'is']
In [14]: c = [5,2,4,2]
In [15]: temp = zip(a, b, c)
In [16]: temp
Out[16]: [(3, 'hi', 5), (2, 'my', 2), (1, 'name', 4), (4, 'is', 2)]
In [17]: temp.sort()
In [18]: _, b, c = zip(*temp)
In [19]: b
Out[19]: ('name', 'my', 'hi', 'is')
In [20]: c
Out[20]: (4, 2, 5, 2)
Or, if you are a fan of one-liners:
In [21]: _, b, c = zip(*sorted(zip(a, b, c)))
Methinks there should be a clever way to do this with the key= argument
to sort, but I can't think of it at the moment...
Kent
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Re: [Tutor] sorting data from multiple arrays
... what is '*' in '*temp'? thanks!
J
Kent Johnson <[EMAIL PROTECTED]> wrote: Jeff Peery wrote:
> hello, I typically run into this problem and I'm not always sure of the
> most efficient way to handle it. I often work with multiple arrays of
> data, say arrays a, b, and c, and I want to sort the elements of b and c
> based on a. for example:
>
> a = [3,2,1,4]
> b = ['hi', 'my','name', 'is']
> c = [5,2,4,2]
>
> I order 'a' from small to large and do the same rearrangement to 'b' and
> 'c':
> a = [1,2,3,4]
> b = ['name', 'my','hi', 'is']
> c = [4,2,5,2]
>
> usually I do some terrible looking for loops and iterate over the whole
> mess is there a clean, efficient way to do this, or is there a nice
> function that would reorder the elements of b and c based on the soring
> of a?
Decorate-sort-undecorate
(http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52234)
to the rescue:
In [12]: a = [3,2,1,4]
In [13]: b = ['hi', 'my','name', 'is']
In [14]: c = [5,2,4,2]
In [15]: temp = zip(a, b, c)
In [16]: temp
Out[16]: [(3, 'hi', 5), (2, 'my', 2), (1, 'name', 4), (4, 'is', 2)]
In [17]: temp.sort()
In [18]: _, b, c = zip(*temp)
In [19]: b
Out[19]: ('name', 'my', 'hi', 'is')
In [20]: c
Out[20]: (4, 2, 5, 2)
Or, if you are a fan of one-liners:
In [21]: _, b, c = zip(*sorted(zip(a, b, c)))
Methinks there should be a clever way to do this with the key= argument
to sort, but I can't think of it at the moment...
Kent
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[Tutor] where to look for help with modbus TCP/IP
hello, I want to use python to communicate (pluck data out of registers) with a controller (walchem, http://www.walchem.com/nav/CMImage.aspx?CMID=0&Name=180277_Modbus_C.pdf). I found great documentation using python sockets and TCP/IP; however I am very unfamiliar with modbus and how modbus TCP/IP is related to TCP/IP. Does anyone know where I might find sample code or a good book describing how to do this? thanks. Jeff - Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] closing a internet explorer com object
hello,
I'm using internet explorer to print out html documents and I'm not sure how
to close it once it is created. How do I do this? below is the simple bit of
code I use to print documents.
thanks!
Jeff
ie = win32com.client.Dispatch("InternetExplorer.Application")
ie.Visible = 0
ie.Navigate(doc_name)
if ie.Busy: sleep(1)
# print the current IE document without prompting
# the user for the printerdialog
ie.ExecWB(win32com.client.constants.OLECMDID_PRINT,
win32com.client.constants.OLECMDEXECOPT_DONTPROMPTUSER)
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[Tutor] executing a script from a script
Hello,
I have a simple wx app that I need some help with. This application uses the
serial ports to communicate with an industrial product. I first check that
my python application is compatible with the industrial product by asking
the industrial product for its revision number. If the revision number is
too old I want to kill my python application and launch an older python
application. To do this I am using the following:
# launch old program
execfile('theoldpythonprogram.py')
# kill this App (wx.Frame object)
self.Destroy()
The problem is that the self.Destroy() seems to kill both the current python
program and the one I just launched. How can I launch a new program and kill
the current one without killing the new one as well?
Thanks!
Jeff
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[Tutor] file locations
Hello, I have a wxapp from which I would like to execute another wxapp. the 'child' wxapp is located in a sub directory of the 'parent' wxapp. The problem I'm having is that I execute the child app from the parent app and it cannot find the modules/images/files etc that it needs because it is looking in the parents directory location and not its own. I want to keep the child wxapp in its own sub directory for organizational purposes, but what is the best way to deal with this problem? thanks, Jeff ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Problem Automating Internet Explorer Printing
Hello,
I'm using the code pasted below to print a document. The code worked great on
my XP machine. I moved it to my W7 machine and it gives the error below. The
weird thing is that it works great if printing a html doc from the web (such as
www.google.com), but it errors when printing a html doc from my desktop. The
document loads as I can see it on the screen, but it chokes when printing.
any ideas?
thanks,
Jeff
line 23, in Print
win32com.client.constants.OLECMDEXECOPT_DONTPROMPTUSER)
File
"C:\Python27\lib\site-packages\win32com\gen_py\EAB22AC0-30C1-11CF-A7EB-C05BAE0Bx0x1x1.py",
line 1186, in ExecWB
, cmdexecopt, pvaIn, pvaOut)
File "C:\Python27\lib\site-packages\win32com\client\__init__.py", line 456, in
_ApplyTypes_
self._oleobj_.InvokeTypes(dispid, 0, wFlags, retType, argTypes, *args),
com_error: (-2147352567, 'Exception occurred.', (0, None, None, None, 0,
-2147221248), None)
import win32com.client
from time import sleep
class Printer():
def __init__(self):
pass
def WaitBusy(self, ie):
while ie.Busy:
sleep(0.5)
def WaitUntilReady(self, ie):
while ie.ReadyState!=4:
sleep(0.5)
def Print(self, doc_name):
ie = win32com.client.Dispatch("InternetExplorer.Application")
ie.Visible = 1
ie.Navigate(doc_name)
# wait for ie to open before printing
self.WaitBusy(ie)
ie.ExecWB(win32com.client.constants.OLECMDID_PRINT,
win32com.client.constants.OLECMDEXECOPT_DONTPROMPTUSER)
## ie.Quit()
p = Printer()
p.Print('test.htm')
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Re: [Tutor] Reading elements in a file
Greg,
You might try…
Import sting
delimiter = ‘.’
f = open('words.txt', "r")
lines = f.readlines()
for line in lines:
line_items = string.split(line,delimiter)
From: tutor-bounces+jeffpeery=seametrics@python.org
[mailto:tutor-bounces+jeffpeery=seametrics@python.org] On Behalf Of Greg
Christian
Sent: Wednesday, May 04, 2011 11:38 AM
To: tutor@python.org
Subject: [Tutor] Reading elements in a file
I am kind of stuck on what is probably a simple thing:
If we have a file of words like this:
“first”,”word”,”in”,”that”,”another”,”part”,”of”,”this”
f = open('words.txt', "r")
words = f.read()
will read the whole file, is there a way to read just the words: first word in
that another part of this
I guess I have to separate on the “,” but I am not quite sure how to go about
this.
Any input would be appreciated.
Regards,
Greg
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[Tutor] USB volume unique volume info
Hello, I am writing a python script to install a program onto a customer computer from a USB drive. To prevent piracy, I want to know if the user has copied my install program to another USB drive. Do USB drives have some unique volume info or another feature that I might query to detect if the program is still operating on the original USB drive? Thanks, Jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
