🌐 Mailman 3 August 2012 - Python-list - python.org

NameError vs AttributeError
by Ulrich Eckhardt Aug. 1, 2012

Aug. 1, 2012

Hi! Using Python 2.7, I stumbled across the fact that 'self.xy' raises an AttributeError if self doesn't have an 'xy' as attribute, but 'xy' will instead raise a NameError. To some extent, these two are very similar, namely that the name 'xy' couldn't be resolved in a certain context, but they don't have a common baseclass. I guess one of the reasons is behind the way that Python handles variable lookup, the plain 'xy' will find local and global names while 'self.xy' will only look into onself. However, this vague idea is far from enough to explain it to someone else. Can someone help me out? Uli

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Re: Pass data to a subprocess
by Grant Edwards Aug. 1, 2012

Aug. 1, 2012

On 2012-08-01, Laszlo Nagy <gandalf(a)shopzeus.com> wrote: >> >> As I wrote "I found many nice things (Pipe, Manager and so on), but >> actually even >> this seems to work:" yes I did read the documentation. > Sorry, I did not want be offensive. >> >> I was just surprised that it worked better than I expected even >> without Pipes and Queues, but now I understand why.. >> >> Anyway now I would like to be able to detach subprocesses to avoid the >> nasty code reloading that I was talking about in another thread, but >> things get more tricky, because I can't use queues and pipes to >> communicate with a running process that it's noit my child, correct? >> > Yes, I think that is correct. I don't understand why detaching a child process on Linux/Unix would make IPC stop working. Can somebody explain? -- Grant Edwards grant.b.edwards Yow! My vaseline is at RUNNING... gmail.com

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CRC-checksum failed in gzip
by andrea crotti Aug. 1, 2012

Aug. 1, 2012

We're having some really obscure problems with gzip. There is a program running with python2.7 on a 2.6.18-128.el5xen (red hat I think) kernel. Now this program does the following: if filename == 'out2.txt': out2 = open('out2.txt') elif filename == 'out2.txt.gz' out2 = open('out2.txt.gz') text = out2.read() out2.close() very simple right? But sometimes we get a checksum error. Reading the code I got the following: - CRC is at the end of the file and is computed against the whole file (last 8 bytes) - after the CRC there is the \0000 marker for the EOF - readline() doesn't trigger the checksum generation in the beginning, but only when the EOF is reached - until a file is flushed or closed you can't read the new content in it but the problem is that we can't reproduce it, because doing it manually on the same files it works perfectly, and the same files some time work some time don't work. The files are on a shared NFS drive, I'm starting to think that it's a network/fs problem, which might truncate the file adding an EOF before the end and thus making the checksum fail.. But is it possible? Or what else could it be?

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YOU MUST KNOW THIS MAN
by BV BV Aug. 1, 2012

Aug. 1, 2012

In The Name Of Allah, Most Gracious, Most Merciful YOU MUST KNOW THIS MAN MUHAMMAD Follow this link http://www.youtube.com/watch?v=9rwYrXbZTM8 Thank you

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Pass data to a subprocess
by andrea crotti Aug. 1, 2012

Aug. 1, 2012

I'm having fun in the world of multiprocessing, and I would like some suggestions. For example suppose I want to create many processes and pass them some data to process (also why they are running). I found many nice things (Pipe, Manager and so on), but actually even this seems to work: class MyProcess(Process): def __init__(self): Process.__init__(self) self.ls = [] def __str__(self): return str(self.ls) def add(self, ls): self.ls += ls def run(self): print("running the process in another subprocess") def procs(): mp = MyProcess() mp.start() # with the join we are actually waiting for the end of the running time mp.join() mp.add([1,2,3]) mp.add([2,3,4]) print(mp) Which is a bit surprising, because it means that I can pass data to an object that is running on another process. Is it because of some magic in the background and can I rely on that or simply I didn't understand how it works?

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Re: Is Python a commercial proposition ?
by lipska the kat Aug. 1, 2012

Aug. 1, 2012

On 31/07/12 14:52, David wrote: > On 30/07/2012, lipska the kat<lipska(a)yahoo.co.uk> wrote: >> On 30/07/12 14:06, Roy Smith wrote: >>> >>> These days, I'm working on a fairly large web application (songza.com). >> >> "We are very sorry to say that due to licensing constraints we cannot >> allow access to Songza for listeners located outside of the United States." >> >> Arse :-( > > A free[1] US proxy could bypass[2] that page ... eg something like > http://www.airproxy.ca/ > > [1] as in beer > [2] for research purposes Oooooh that's a bit good isn't it, just for research purposes of course. There's one (as in 1 above) in the pump for you. lipska -- Lipska the Kat: Troll hunter, sandbox destroyer and farscape dreamer of Aeryn Sun

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Re: [ANN] pyknon: Simple Python library to generate music in a hacker friendly way.
by Peter Billam Aug. 1, 2012

Aug. 1, 2012

On 2012-07-30, Pedro Kroger <kroger(a)pedrokroger.net> wrote: > Pyknon is a simple music library for Python hackers. With Pyknon > you can generate Midi files quickly and reason about musical > proprieties. It works with Python 2.7 and 3.2. > ... a basic example to create 4 notes and save into a MIDI file: > from pyknon.genmidi import Midi > from pyknon.music import NoteSeq > notes1 = NoteSeq("D4 F#8 A Bb4") > midi = Midi(1, tempo=90) > midi.seq_notes(notes1, track=0) > midi.write("demo.mid") > It's available on PyPI and its homepage is > http://kroger.github.com/pyknon/ > Pedro > http://pedrokroger.net http://musicforgeeksandnerds.com I'll check it out. It probably fits into a whole software ecosystem that you're putting together ... It's a crowded area, e.g. my midi stuff is at: http://www.pjb.com.au/midi/index.html and I'd probably do the above example by: ~> muscript -midi <<EOT >demo.mid | 3/4 2.0 =1 treble 4 D 8 [F# A] 4 Bb EOT see: http://www.pjb.com.au/muscript/index.html but also relevant would be my MIDI.py, see: http://www.pjb.com.au/midi/MIDI.html which is also available in call-compatible Lua version: http://www.pjb.com.au/comp/lua/MIDI.html and is closely related to the Perl CPAN module. You could consider posting Pyknon to comp.music.midi ; it's very low traffic, but some real gurus lurk there. All the best with your music, Peter -- Peter Billam www.pjb.com.au www.pjb.com.au/comp/contact.html

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