🌐 Mailman 3 July 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.

5 6

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

4 3

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

2 1

curses
by max baseman Aug. 3, 2007

Aug. 3, 2007

hello all sorry to bother I'm working on my first curses program ive been wanting to learn curses for a while now and now that a have a lop top with fedora core running in run level 3 ware im trying to program all the tools i'll use but curses will be my only gui ALAN has been helping me with this program import curses from time import sleep scr=curses.initscr() population=0 seconds=0 try: scr.nodelay(1) scr.leaveok(0) max_y, max_x = scr.getmaxyx() while 1: sleep(1) second=seconds=+1 population=population+2.5 scr.addstr(0,0,"seconds",seconds) scr.addch,max_y/2, max_x/2, str(population)[0] scr.refresh() finally: curses.endwin() depending on ware i run this i get different results on may mac OSX 10.4 i only get a wired second thing in the top left corner that looks like this secooes and when i run this on fedora core 6 i get the seconds word in top left but no number and i get a single digit in the midle that changes i think the single digit is part of population but not all i cant find out what is wrong any help would be great :)

2 1

os.path.exists(path) returns false when the path actually exists!
by Iyer Aug. 3, 2007

Aug. 3, 2007

os.path.exists(path) returns false when the path actually exists! When I do this: >>> os.path.exists("c:\\winnt\\file_name") I get this: >>> False Actually the file exists in c:\winnt, and I can confirm it exists there, but os.path.exists isn't returning True, when it should be.. Is this a bug ? iyer --------------------------------- Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center.

12 19

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

3 3

Which GUI?
by scott Aug. 2, 2007

Aug. 2, 2007

Hi, now that I have a very basic understanding of Python I would like to take a look at programming in a GUI. Which GUI is generally the easiest to learn? -- Your friend, Scott Sent to you from a Linux computer using Ubuntu Version 7.04 (Feisty Fawn)

12 27

shelves behaving badly
by Luke Jordan Aug. 2, 2007

Aug. 2, 2007

i've implemented a database as a shelve of record class instances. some of the fields in each record are dictionaries. i needed to parse info from 3 different reports into the dictionary fields in each record instance. i wrote the code to do this and tinkered it to fit the different reports (i.e. information being in different columns, etc.). for 2 of the reports, it runs fine. the required info turns up in the shelve after i run the code, and i can exit and reenter python, open the shelve, and it's all still there, where it should be. i've quadruple checked the code for the third report, and it looks like it should work. in fact it runs, and reports back that it did everything i told it to do; this includes checking results as they occur at runtime. however, when i reopen the shelve, none of that data is there. writeback is set to True, and I didn't forget to close the shelve at the end of my code. Now, if I open the shelve in the same shell as the script ran in, right after I run it, I get the updated shelve. but any other method of opening the shelve results in the shelve missing the data from the third report. Any ideas what's going on here? -- Luke

2 2

passing form data into a class
by tpc247＠gmail.com July 31, 2007

July 31, 2007

dear fellow Python enthusiasts, let's say I have a dictionary of keys and values obtained from a form submitted by a user. For each submitted form I will create the Application and Candidate classes, and I want to be able to call Application(Candidate(**submitted_data)).display() to create an html representation of the user submitted data. Depending on the applicant's preferences and location, the number of fields on the form, and thus the size of this dictionary, is variable, and not all fields are required. I seem to recall a setargs function in Python that would take any argument passed into a class and set that argument as a member variable in a class. A Google search turned up no such construct, so here I am asking you, is there a way for me to create a class that accepts a dictionary of submitted data and uses each key ad value to create a corresponding member variable ? The current way I do this is with a very long argument list, and line by line: class Candidate(object): def __init__(self, full_name, address_line_1, city, postal_code, email, desired_program, telephone=None, disabled=None, can_receive_media=None, media_sent_to=None, ...): self.full_name = full_name self.address_line_1 = address_line_1 self.city = city self.postal_code = postal_code self.email = email self.desired_program = desired_program class Application(object): def __init__(self, candidate): self.candidate = candidate def display(self): pass

5 4

Re: [Tutor] attribute error - quick addition
by Sara Johnson July 30, 2007

July 30, 2007

No luck finding tutors. I don't make enough. It seems to be this script that's throwing me off. But I understand and I'll take what I've learned to date and something will work eventually. Thanks for your concern and support. Sara ----- Original Message ---- From: Alan Gauld <alan.gauld(a)btinternet.com> To: tutor(a)python.org Sent: Monday, July 30, 2007 5:55:56 PM Subject: Re: [Tutor] attribute error - quick addition "Sara Johnson" <sarliz73(a)yahoo.com> wrote > Sorry... I'm still learning about lists, tuples, etc... Sarah, You've been hanging around with this list for a few weeks now. If you just took one day out to go through the official tutorial then you should know enough to answer all of these questions. Seriously, invest the time to learn the language and you will cut the time messing around and solve your problem a lot sooner. Hacking away in the hope of stumbling on a solution and asking questions here if it doesn't work is one of the most inefficient ways to get your job done. (Both for you and us!) We are all here to help people learn Python and answer questions but you will make it easier on all of us if you work through a tutor to get the basics clearly fixed. Not only will your problem be easier to solve but the answers we give will make more sense too! Alan G. _______________________________________________ Tutor maillist - Tutor(a)python.org http://mail.python.org/mailman/listinfo/tutor ____________________________________________________________________________________ Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center. http://autos.yahoo.com/green_center/

2 1