🌐 Mailman 3 May 2007 - Tutor - python.org

Send binary/hex data to a TCP socket
by Tod Haren July 19, 2011

July 19, 2011

I need to send a server at the other end of a socket a 36 byte "frame", where each byte represents a specific field in the custom data structure. (If there are any Ham operators reading this, I'm talking about the AGW Packet Engine) The documentation for the server says to initialize each field to a binary zero(0x00). How do I get a binary zero in Python? The next step is to send this all to the server and subsequently receive a similarly formated frame. A very basic frame looks something like this(modified from documentation): |00 00 00 00 4D 00 00 00 00 00 00 00 00 00 00 00 |....M........... |00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................ |00 00 00 00 |.... My problem is that hex(0) return '0x0' and hex(ord('M')) returns '0x4d'. If I concatonate these all together then the socket receives 109 bytes instead of 36. The documentation examples are in C++, so they are little help to me. The examples make use of the MoveMemory function for building the frames, but I'm clueless what that does. Pseudo code for the frame above: l = [] for i in xrange(36): l.append(hex(0)) l[4]=hex(ord('M')) d='' d=d.join(l) #I need some other data type to send besides a string! sock.send(d) #send the 36 bytes to the socket Any pointers or references would be greatly appreciated.

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Tracking time
by Michael Key Jan. 6, 2010

Jan. 6, 2010

I am trying to develop a project tracking program that would allow you to track hours and minutes spent on several different projects and store he data in a database for printing. Any help would be appreciated. Mike

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difflib.SequenceMatcher with get_matching_blocks is incorrect
by Thomas Nov. 5, 2007

Nov. 5, 2007

I'm trying to write a program to test someone's typing speed and show them their mistakes. However I'm getting weird results when looking for the differences in longer (than 100 chars) strings: import difflib # a tape measure string (just makes it easier to locate a given index) a = '1-3-5-7-9-12-15-18-21-24-27-30-33-36-39-42-45-48-51-54-57-60-63-66-69-72-75-78-81-84-87-90-93-96-99-103-107-111-115-119-123-127-131-135-139-143-147-151-155-159-163-167-171-175-179-183-187-191-195--200' # now with a few mistakes b = '1-3-5-7-l-12-15-18-21-24-27-30-33-36-39o42-45-48-51-54-57-60-63-66-69-72-75-78-81-84-8k-90-93-96-9l-103-107-111-115-119-12b-1v7-131-135-139-143-147-151-m55-159-163-167-a71-175j179-183-187-191-195--200' s = difflib.SequenceMatcher(None, a ,b) ms = s.get_matching_blocks() print ms [(0, 0, 8), (200, 200, 0)] Have I made a mistake or is this function designed to give up when the input strings get too long? Thanks in advance, Thomas

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ossaudiodev, pygtk, and flushing buffers
by Matthew White Aug. 3, 2007

Aug. 3, 2007

Hello All, I'm writing a little audio player that plays voicemail files. (I realize I'm reinventing the wheel, but it's still fun.) The problem I'm experiencing is that I'm hearing the last fraction of the sound clip twice, either when the clip is done playing or when the program exits. I've tried a few things and none of them have worked. The bit of code that does the playing is here: def play(self): if self.data_written < self.file_length: buf = self.data.read(self.buf_size) self.data_written += self.dsp.write(buf) self.percent_done = self.data_written / self.file_length if self.data_written == self.file_length: self._reopen_audio_device() This causes the second playing of the "last little bit" when the end of the file is reached. When I don't include the second if statement, the "last little bit" gets played when the program exits. According to the documentaiton, closing the audio device will flush any data in the sound card buffer. I guess what I'm hearing is that buffered clip being flushed. I've thought about using the mixer device to put the volume to zero, flush the buffer, then turning the volume back up again, but that seems like a hack. If anyone decides to use this program, you'll need to use a .wav file and change the value of self.sample_rate in vmPlayer.py from 8000 to 44100 (or whatever rate your file is encoded in) (Also, I plan on auto-detecting the sample rate in the future. I hard coded 8000 because that's the rate the voice mail system uses.) See attached files for the code. -mtw

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SPE - Stani's Python Editor ?
by Vladimir Strycek June 24, 2007

June 24, 2007

Hi all, some time ago i instaled SPE with python 2.4... it works very good... but yesterday my pc crash completly ( some dll went missing somehow :-) )... so after format and reinstalling of windows i begin to install all my programs back... When i come to python i download new 2.5 version and only version for win i could find is SPE-0.8.2.a-wx2.6.1.0-py24 which doesnt work... :-( newer version ist just rpm and i need exe for win... any idea if there will be exe or any more development in SPE cause homepage is not running etc... Or can you suggest similar IDE for python... ? Thanks Best regards Vladimir

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numbers and ranges
by Jon Crump June 5, 2007

June 5, 2007

Dear all, Here's a puzzle that should be simple, but I'm so used to words that numbers tend to baffle me. I've got fields that look something like this: 1942. Oct. 1,3,5,7,8,9,10 I need to parse them to obtain something like this: <sometag start="1942-10-01"/> <sometag start="1942-10-03"/> <sometag start="1942-10-05"/> <sometag start="1942-10-07" end "1942-10-10"/> The xml representation is incidental, the basic problem is how to test a list of integers to see if they contain a range, and if they do, do something different with them. I'm sure this is the question of a rank tyro, but the denizens of this list seem tolerant and gentle. Many thanks.

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[Fwd: Re: trouble with "if"]
by Brian van den Broek June 2, 2007

June 2, 2007

Another fwd, folks. Brian vdB -------- Original Message -------- Subject: Re: [Tutor] trouble with "if" Date: Tue, 29 May 2007 23:28:46 -0500 From: Adam Urbas <jped.aru(a)gmail.com> To: Brian van den Broek <broek(a)cc.umanitoba.ca> References: <BAY103-W11DE2E62FD41449A952D68B12F0(a)phx.gbl> <465C64A4.60602(a)cc.umanitoba.ca> <ef52818c0705292107n1ee0c105k54c02ccf4d85f7c6(a)mail.gmail.com> I'm having trouble with the parentheses after the def thing(). IDLE says that there is something wrong with it. If I type something between them, it says that there is something wrong with the quotation marks. If I just leave it like (), then it says that something is wrong with what is after the parentheses. Unless my code is supposed to go between the parentheses. I'll try that. On 5/29/07, Adam Urbas <jped.aru(a)gmail.com> wrote: > In the def welcome(), what do you put in the parentheses? Another > question, what code do you use for ending the program. I want the > user to be able to cancel the program from the main menu, where it > asks you to choose circle, square, etc. Or even perhaps allow the > user to go back to a previous menu, well I suppose that would be the > def thing() code. But what if they were at the part where the program > was asking them to input the radius, how would I give them the option > of returning to the list of given measurements of a circle? > > On 5/29/07, Brian van den Broek <broek(a)cc.umanitoba.ca> wrote: > > adam urbas said unto the world upon 05/29/2007 12:39 PM: > > > The scary part is, I think I understand this. I copied your last > > > example and put it in IDLE and it doesn't like you code. Never > > > mind. I figured it out. So that is so it will notify you if your > > > choice is invalid. Nice lil tidbit of information there. I'll be > > > sure to use this. Oh and while your here, I'd like to ask about > > > loops I guess they are. I want to have the program go back to the > > > part where it asks for the user to select an option after it has > > > run one of its if statements.Like, when the user tells it, > > > "circle," then "radius," then enters the radius: here I would like > > > the program to go back and ask the user if they want to do anything > > > else, like find the area of a square, instead of the circle. Would > > > I have to tell python to print all those selections again, or would > > > there be a way to just return to the beginning?Thanks,Au> Date: > > > > > > Hi Adam, > > > > Again, I cut the mess, but I expect that if you use the gmail account > > you just posted about here on in, that will be the end of it. > > > > I'm glad that you are starting to have the warm glow of understanding :-) > > > > What you are asking about here is one reason why functions are so > > useful. They allow you (more or less) to give a name to a chunk of > > code, and then you can rerun that chunk at will by invoking the name. > > > > Given the problem you want to solve, I'd structure my code something > > like the following. Most of the details need to be filled in, but this > > is the skeletal structure. > > > > > > def welcome_message(): > > # Some actions to invoke when the user starts the program > > print "Welcome to this program." > > > > def display_menu(): > > # Insert code for showing the user the menu of options > > pass > > > > def circle_area(): > > # insert code here to ask user for the radius, compute the area, > > # and display the result. You might well want to divide that up > > # into other functions that this one calls. > > pass > > > > def square_area(): > > # Likewise > > pass > > > > # And so on, for each shape that you wish to handle > > > > def exit_message(): > > # Some actions to invoke when the user chooses to terminate > > # the program. > > print "Thank you for using this program. Goodbye." > > > > def prompt_user(): > > # Here is where the sort of code I showed you before would go. > > # I'd include an option, say 0, for exiting, which, when the > > # user picks it, you call exit_message() > > > > while True: > > try: > > choice = int(raw_input("Please make your choice ")) > > if choice < 0 or choice > 2: # Adjust to suit options > > raise ValueError > > break > > except ValueError: > > print "Please make a choice from the options offered." > > > > # sends the choice back to the code that called prompt_user > > # We won't get here until a good choice has been made > > return choice > > > > def main(): > > # The main function driving your program. It might look > > # something like this: > > welcome_message() > > > > while True: # This will loop forever until you break out > > display_menu() > > choice = prompt_user() > > > > if choice == 0: > > exit_message() > > break # Terminate the while loop > > elif choice == 1: # Assuming 1 was the option for circle > > circle_area() > > elif choice == 2: > > square_area() > > # And so on > > > > print "Please make another choice:" # Go back to top of loop > > > > > > if __name__ == '__main__': > > # This will run if you run the script, but not if you import it. > > main() > > > > > > This has not been tested (it is only an outline) but it does pass the > > only so reliable eyeball check :-) > > > > I'd suggest you try filling this sketch out to be useful, and post if > > you run into troubles. > > > > Best, > > > > Brian vdB > > >

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Starting with wxPython
by Alan Gilfoy June 1, 2007

June 1, 2007

I'm not quite there yet, but I want to get into using GUIs in Python soon, and I plan to use wxPython to do so. What, do you think, is the best tutorial out there for wxPython? Also, what happens when you code for some GUI feature and run the script in your IDE, such as IDLE? Will the graphical features properly appear?

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(no subject)
by Treloar, Nick June 1, 2007

June 1, 2007

how do you import sounds This message is intended for the addressee named and may contain privileged information or confidential information or both. If you are not the intended recipient please delete it and notify the sender.

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creating a buffer object from a file ?
by Iyer May 31, 2007

May 31, 2007

I think this got lost among the threads: thanks, alan for your helpful response. in reality what is a buffer object used for ? reading a file itself creates a string as in itself, file_handle = file ("path_to_file") file_data = file_handle.read() # file_data is a string, so why is a buffer object is needed ? the data in the binary file is just raw binary. I apologize for replying to the existing subject. Thanks for letting me know. I shall make sure this doesn't happen again. thanks iyer --- Alan Gauld <alan.gauld(a)btinternet.com> wrote: > "Iyer" <maseriyer(a)yahoo.com> wrote > > > How do I go about creating a buffer object from > > a file containing binary data ? I have a function > > that accepts only buffer objects for it's > parameters > > Can you define what you mean by a buffer object? > Python uses duck typing so, unless the function has > been badly coded with an explicit type check, it > should accept any object that supports the methods > used. > > If you really do need a buffer the docs say: > > ----- > Buffer objects are not directly supported by Python > syntax, but can be created by calling the builtin > function buffer(). They don't support concatenation > or repetition. > ----- > > Which was new to me. But some experimentation > with the interpreter shows: > ---- > class buffer(object) > | buffer(object [, offset[, size]]) > | > | Create a new buffer object which references the > given object. > | The buffer will reference a slice of the target > object from the > | start of the object (or at the specified > offset). The slice will > | extend to the end of the target object (or with > the specified > size). > --- > and > ---- > >>> b = buffer('fredrica', 2,4) > >>> b[:] > 'edri' > ---- > > So we can see how to create a buffer object. > You want to do it with a binary file. You can read > the content > of a binary file using the struct module. But you > need to know > what kind of data is in your file. To create a > buffer you need > a string. So do you want your buffer to process the > raw binary > bytes as if they were a string? Or do you want to > convert the > binary data and then convert it again into a string > representation? > > Either is possible but you need to decide which you > need. > > BTW Please don't post new subjects to the list by > replying > to an existing subject. For those using threaded > readers it > buries your post insife another thread, in this case > 3 levels > deep in one about MSSQL! I only just noticed it. Its > better > to start a fresh message. After all its not exactly > difficult to > type tutor(a)python.org in the to line! :-) > > HTH, > > -- > Alan Gauld > Author of the Learn to Program web site > http://www.freenetpages.co.uk/hp/alan.gauld > > > > _______________________________________________ > Tutor maillist - Tutor(a)python.org > http://mail.python.org/mailman/listinfo/tutor > ________________________________________ ____________________________________________________________________________________ Food fight? Enjoy some healthy debate in the Yahoo! Answers Food & Drink Q&A. http://answers.yahoo.com/dir/?link=list&sid=396545367

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