🌐 Mailman 3 May 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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a question about symbol
by linda.s June 2, 2006

June 2, 2006

When I test the following code, I got something like (use 80 as argument): 80?F=27?C Why '?' appear? # code import string, sys # If no arguments were given, print a helpful message if len(sys.argv)==1: print 'Usage: celsius temp1 temp2 ...' sys.exit(0) # Loop over the arguments for i in sys.argv[1:]: try: fahrenheit=float(string.atoi(i)) except string.atoi_error: print repr(i), "not a numeric value" else: celsius=(fahrenheit-32)*5.0/9.0 print '%i\260F = %i\260C' % (int(fahrenheit), int(celsius+.5))

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XML Parsing Woes.
by doug shawhan June 1, 2006

June 1, 2006

Having been dragged kicking and screaming into the fussy, fussy world of XML, I find myself in a pickle. I keep getting an error complaining of a missing end-tag: : XML Parse error. <BR>XML Error Text: "; nested exception is: org.xml.sax.SAXParseException: The element type "Description" must be terminated by the matching end-tag "</Description>".". Now of course, I have saved my output and found the end-tag to be there. I have stripped out everything I can think of that might cause the parser to puke. The string enclosed by the <Description> tags varies from a few characters to a couple of thousand: all fail with the same error. I am very new to XML and find it's jargon fairly impenetrable. Is there a handy python module that can one can use to scan XML output for errors? I know the mistake is probably mine ... or perhaps I have actually run on to a bug in the remote application? :-) (Riiiiight!) Thanks!

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_next
by Christopher Spears May 31, 2006

May 31, 2006

How does this script work? #!/usr/bin/python class IteratorExample: def __init__(self, s): self.s = s self.next = self._next().next self.exhausted = 0 def _next(self): if not self.exhausted: flag = 0 for x in self.s: if flag: flag = 0 yield x else: flag = 1 self.exhausted = 1 def __iter__(self): return self._next() def main(): a = IteratorExample('edcba') for x in a: print x print '=' * 30 a = IteratorExample('abcde') print a.next() print a.next() print a.next() print a.next() print a.next() print a.next() if __name__ == '__main__': main() Here is the output: d b ============================== b d Traceback (most recent call last): File "./python_101_iterator_class.py", line 35, in ? main() File "./python_101_iterator_class.py", line 29, in main print a.next() StopIteration I think a lot of my confusion comes from not understanding what _next is. I got this script from an online tutorial at python.org. Is there a better way to write the script, so I can actually understand it? "I'm the last person to pretend that I'm a radio. I'd rather go out and be a color television set." -David Bowie "Who dares wins" -British military motto "I generally know what I'm doing." -Buster Keaton

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Re: [Tutor] Enumeration and constant
by Bob Gailer May 29, 2006

May 29, 2006

Please always reply to the list as well as me. Others may be able to help, and we all learn from our interactions. Brendan Cheng wrote: > how about custom constant type? > Does python provide? No. Python tries to be as "light" as possible. There is a convention amongst Python programmers to use upper case names to represent constants, e.g. RED = 3. -- Bob Gailer 510-978-4454

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how to use the "image" option for Button widget in Tkinter
by Bernard Lebel May 29, 2006

May 29, 2006

Hello everyone, I'm looking for a way to put an image on a button in a Tkinter GUI, but for the life of me I just can't find any clear directions about how to do that. No matter where I look, the only documentation I can find is this (Fred Lundz): "image (image). The image to display in the widget. If specified, this takes precedence over the text and bitmap options." How do you format the image argument value? I have try absolute paths, I always get a path not found error. Also, what is the file format to use? Thanks Bernard

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Enumeration and constant
by Brendan Cheng May 29, 2006

May 29, 2006

Hi, I wander how to setup the enumeration type and constant in Python, which I couldn't find the topic in the help file. I'm using python 2.4.3 please give me an example of it as well Thanks, Brendan

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a question about symbol
by ron May 29, 2006

May 29, 2006

When I run this program using your code on Ubuntu Linux, I get: ~$ ./c2f.py 44 44\uffffF = 7\uffffC Please notice that the code you have posted has indentation block errors. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Enumeration and Constant
by Brendan Cheng May 29, 2006

May 29, 2006

Hi, I wander how to setup the enumeration type and constant in Python, which I couldn't find the topic in the help file. I'm using python 2.4.3 please give me an example of it as well Thanks, Brendan

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MySQLdb.converters.escape() type error
by Jan Eden May 28, 2006

May 28, 2006

Hi, after upgrading to MySQL 5 and MySQLdb 1.2.1_p2, I have the following problem: self.db=MySQLdb.connect(host=host, user=user, passwd=passwd, db=db, cursorclass=MySQLdb.cursors.DictCursor) stringel = 'Some string' stringel = self.db.escape(stringel) File "./test.py", line 12, in ? stringel = self.db.escape(stringel) TypeError: no default type converter defined I checked the documentation for MySQLdb.converters and saw that the escape() function takes a dictionary as an obligatory second argument. This is odd, because I have always been using escape(string) without a problem. The changes in MySQLdb 1.2.1_p2 list: "Mapped a lot of new 4.1 and 5.0 error codes to Python exceptions" Could someone point me to the problem in the MySQL side? Thanks in advance! - Jan -- Any technology which is distinguishable from magic is insufficiently advanced.

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