🌐 Mailman 3 July 2006 - Tutor - python.org

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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Using python to create and save a Ms Word file
by Andrew Robert Aug. 23, 2006

Aug. 23, 2006

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Everyone, I wasn't entirely satisfied with the Ms Word solution because it requires the program run on Windows and have Office installed. As an alternate solution, I created the program listed below to read a file and create a RTF file format document from it. The program is not platform dependent but it does require installation of the PyRTF module. I hope someone finds this useful/interesting. #!C:\Python24\python # # program: rtfmaker.py # Author: Andrew Robert # # Function: Take a supplied file and dump its contents to an RTF file # This code is platform independant. # # Ver Date Programmer Modification # 1.0 07/21/06 AAR Initial Creation # 1.1 added argument and source/target file testing import sys, time, string, stat, os from PyRTF import * from optparse import OptionParser def MakeFile(lines): """ Create the RTF file """ doc = Document() ss = doc.StyleSheet section = Section() doc.Sections.append( section ) # Append lines from source file for line in lines: section.append( line ) return doc def OpenFile( name ): return file( '%s' % name, 'w' ) def file_test(file): """ Tests user supplied file to see if it exists and contains data. If the input file does not exist or is empty, return a warning code """ if (0 == os.path.isfile(file) or (0 == os.stat(file)[stat.ST_SIZE])): return 1 else: return 0 def run_tests(input, output): """ Test source file to ensure it exists and contains data """ if file_test(input) == 1 : print "\nError: Source file not found or is empty." parser.print_help() sys.exit(1) # Test target file to prevent accidental clobbering if file_test(output) == 0 : print "\nError: Target file already exists." parser.print_help() sys.exit(1) def test_options(infile, outfile): """ Verify that required values are specified on commmand line and that specified port is within range """ if not infile : print "\nError: No input file specified" parser.print_help() sys.exit(1) if not outfile : print "\nError: No input file specified" parser.print_help() sys.exit(1) if __name__ == '__main__' : parser=OptionParser() parser.add_option("-i", "--input" , dest="infile", help="Input FILE" , metavar="FILE") parser.add_option("-o", "--output", dest="outfile", help="Output file", metavar="FILE") (options, args) = parser.parse_args() test_options( options.infile , options.outfile ) run_tests(options.infile , options.outfile) DR = Renderer() lines = open(options.infile,"r").readlines() rtffile = MakeFile(lines) # Write the new RTF file to disk DR.Write( rtffile, OpenFile( options.outfile ) ) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (MingW32) Comment: GnuPT 2.7.2 iD8DBQFEwO9uDvn/4H0LjDwRAlHSAJ9KIzPYT2YHdK8MptBS8JSIdt8dZACgsfKi nZQ3Bs71jsbFplmwbnVEIgI= =ZPSo -----END PGP SIGNATURE-----

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The In Operator
by Steve Haley Aug. 15, 2006

Aug. 15, 2006

I am trying to make my way through a book on Python ("Python Ptogramming for the Absolute Beginner") and have run into some code in the book (and on the author's accompanying CD) that won't work. I suspect that it might be because my version of Python is too old (2.1). The code includes the in operator as follows: if "Dancing Baloney" in geek: ... print "I know what Dancing Baloney is." ... else: ... print "I have no idea what Dancing Baloney is." where geek is the nam of a dictionary. "Dancing Baloney is not in the dictionary so I should get the second print statement as a result but instead get: Traceback (most recent call last): File "<interactive input>", line 1, in ? TypeError: 'in' or 'not in' needs sequence right argument The error message is the same when I run the author's code but the error statement itself seems to indicate that there IS an in operator. I guess I really have a three questions. Is the in operator in version 2.1 of Python? If it is, what is the syntax? (I tried to find it in the help etc. and couldn't.) Finally, my version of 2.1 came bundled with other software (ESRI ArcView). Is anyone out there an ESRI user who can tell me if I can I go ahead and download a newer version without messing up my ArcView installation? Thanks, Steve

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Notes on namespaces, scopes, etc
by Dave Kuhlman Aug. 3, 2006

Aug. 3, 2006

I've written up a few notes on Python namespaces and scopes. If anyone has corrections, comments, or suggestions, I'd appreciate them. You can find my comments here: http://www.rexx.com/~dkuhlman/python_comments.html#namespaces I wrote these notes because I found that I did not understand Python namespaces as well as I thought I did. Writing the comments seemed like a good way to work through and learn about namespaces, scopes, variables, bindings, etc. By the way, I was motivated to write these notes because of the "loops to assign variables" thread on this list a few days ago. I'm hoping that my notes show that I learned from that thread. Dave -- Dave Kuhlman http://www.rexx.com/~dkuhlman

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Re: [Tutor] syntax error
by Carroll, Barry July 31, 2006

July 31, 2006

Hello Chris, > -----Original Message----- > Date: Mon, 31 Jul 2006 15:29:13 -0700 (PDT) > From: Christopher Spears <cspears2002(a)yahoo.com> > Subject: [Tutor] syntax error > To: tutor(a)python.org > Message-ID: <20060731222913.40214.qmail(a)web51615.mail.yahoo.com> > Content-Type: text/plain; charset=iso-8859-1 > > My brain has gone squishy. I am combining a linked > list with a priority queue. This is the last exercise > out of How To Think Like A Computer Scientist (Chapter > 19). > <<snip>> > > def insert(self, cargo): > node = Node(cargo) > node.next = None > if self.length == 0: > # if list is empty, the new node is head and last > self.head = self.last = node > elif node.cargo > self.head.cargo: > node.next = self.head > self.head = node > else node.cargo <= self.head.cargo: > self.last.next = node > self.last = node > self.length = self.length + 1 > <<snip>> > > Here is the error message: > >>> from linkedPriorityQueue import * > Traceback (most recent call last): > File "<stdin>", line 1, in ? > File "linkedPriorityQueue.py", line 27 > else node.cargo <= self.head.cargo: > ^ > SyntaxError: invalid syntax > > I am not sure what this means. Everything is spelled > correctly. > > -Chris > The syntax error occurs just after the "else". Unlike "if" and "elif", "else" does not take an expression. It covers any cases left over after the "if" clause and all of the "elif" clauses have been tried and failed. The expression "node.cargo <= self.head.cargo" is therefore logically unnecessary. Python (and all other programming languages I know of) enforces this by making it illegal to put an expression in an "else" clause. I don't have access to "How To Think Like A Computer Scientist", so I can't point you to the section that discusses this, but I'm sure it's in there somewhere. Look in the index for "else clause", "if-elif-else statement" or some entry like that. HTH. Regards, Barry barry.carroll(a)psc.com 541-302-1107 ________________________ We who cut mere stones must always be envisioning cathedrals. -Quarry worker's creed

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syntax error
by Christopher Spears July 31, 2006

July 31, 2006

My brain has gone squishy. I am combining a linked list with a priority queue. This is the last exercise out of How To Think Like A Computer Scientist (Chapter 19). class Node: def __init__(self, cargo=None, next=None): self.cargo = cargo self.next = next def __str__(self): return str(self.cargo) class ImprovedQueue: def __init__(self): self.length = 0 self.head = None self.last = None def isEmpty(self): return (self.length == 0) def insert(self, cargo): node = Node(cargo) node.next = None if self.length == 0: # if list is empty, the new node is head and last self.head = self.last = node elif node.cargo > self.head.cargo: node.next = self.head self.head = node else node.cargo <= self.head.cargo: self.last.next = node self.last = node self.length = self.length + 1 def remove(self): cargo = self.head.cargo self.head = self.head.next self.length = self.length - 1 if self.length == 0: self.last = None return cargo Here is the error message: >>> from linkedPriorityQueue import * Traceback (most recent call last): File "<stdin>", line 1, in ? File "linkedPriorityQueue.py", line 27 else node.cargo <= self.head.cargo: ^ SyntaxError: invalid syntax I am not sure what this means. Everything is spelled correctly. -Chris

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The Self
by Sebastian Smith July 31, 2006

July 31, 2006

I am new to Python, real new. I am loving the language and learning fast but I have hit a wall with the 'self'. I have Googled and searched and read a few definitions but it still doesn't make sense to me. I would love to hear some of your 'layman's definitions' on the self. Thank you all, Ben.

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question about headers and smtplib
by shawn bright July 31, 2006

July 31, 2006

Hey there, me again with another question about headers.. if i use my python script to send an email, it gets rejected by some providers. but another app that i use can send the same email and it gets thru. i have sent myself test messages from both apps and looked at the headers. the only difference in one from the other is that in the headers of the other app (not my python script) there exist the following lines: MIME-Version: 1.0 X-Mailer: OstroSoft SMTP Control (4.0.20) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7-bit i do not understand how to make mine work and include (or configure to) the above example. anyone point me in a right direction ? thanks, shawn

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problem with rejected mail smtplib
by shawn bright July 30, 2006

July 30, 2006

Hello there, i have a customer list, each with a number of email address that we send notifications to via text message. the problem is, there are a number of providers ( just two ) that reject our messages. the script goes a little something like this : Address = 'going(a)somewhere.net' >From = 'me(a)myhost.net' message = 'From: me(a)myhost.net\r\nTo: %s\r\nSubject: %s\r\n\r\n%s' % (Address,'alert',message) server.sendmail(From, Address, message) most of the time it goes thru ok. but only some providers have a problem. However, those same providers get messages if i send them thru Evolution. any ideas of what to check out? thanks -sk

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visualization
by Сергій July 30, 2006

July 30, 2006

I have a world (environment), where live different objects. And all objects like to move. This is the code: """ import random, time, Tkinter class Object: def __init__ (self, x=10, y=10): self.name = random.randint(0, 100000) self.x = x self.y = y def __repr__ (self): return str(self.name) def display(self, canvas, x, y, width, height): """Display an image of this Object on the canvas.""" pass def rand_vec(self): return random.randint(-1, 1), random.randint(-1, 1) class Environment: def __init__ (self): self.objects = [] def step(self): for obj in self.objects: old_x, old_y = obj.x, obj.y change_x, change_y = obj.rand_vec() obj.x, obj.y = old_x + change_x, old_y + change_y print obj.name, '\t:\t ', old_x, old_y,' -> ', obj.x, obj.y def run(self, steps=10): """Run the Environment for given number of time steps.""" for step in range(steps): self.step() time.sleep(2) def add_object(self, object): print object.name, ' was added to environment' self.objects.append(object) print '\tBORN' env = Environment() for obj in range(10): child = Object() print child, ' was born' env.add_object(child) print '\tLIFE' env.run(100) """ And now I want to visualizate this world. What modules can you advise me for "easy" visualization? "Easy" means that it would be really nice if I could do vizualization with minimum change of existing classes. Thanks in advance.

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