🌐 Mailman 3 January 2011 - Tutor - python.org

Wave module
by Alex Krycek Feb. 12, 2015

Feb. 12, 2015

Hello, I'm trying to join two .wav files with the wave module. But when I try to use wave.open(filename, "rb") I receive the following error: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "F:\PortablePython1.0\lib\wave.py", line 483, in open return Wave_read(f) File "F:\PortablePython1.0\lib\wave.py", line 162, in __init__ self.initfp(f) File "F:\PortablePython1.0\lib\wave.py", line 143, in initfp self._read_fmt_chunk(chunk) File "F:\PortablePython1.0\lib\wave.py", line 264, in _read_fmt_chunk raise Error, 'unknown format: %r' % (wFormatTag,) wave.Error: unknown format: 85 I read somewhere that there are various wave formats, only some supported by Python. Is this true? If so, is there any way I can convert my wave files into a supported kind? Thanks!

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Running .py files in shell
by Kevin Rapley Sept. 22, 2011

Sept. 22, 2011

Hello all, I am new to programming and have opted to learn Python as I hear it is a good first language. I am currently going through the exercises in 'How to Think Like a Computer Scientist: Learning with Python 2nd Edition'. I am running Mac OSX v10.6.4 Snow Leopard I am running Python 2.6.1 I have a couple of questions: 1. How do I execute .py files in the command line shell? I have my files in /Users/Kevin/python-exercises/ and am opening python in shell from that directory 2. How do I install GASP which is referenced in chapter 4? The instructions in this book are not complete. I have researched and found a reference on Stack Overflow which is contributed to by GASP programmers http://stackoverflow.com/questions/1024862/how-do-i-install-gasp-for-python… I have MacPorts installed and have attempted to install PyObjC, which is referenced as a prerequisite to PyGame and GASP. I get the following error when attempting to install PyObjC: sudo port install py-pyobjc Password: ---> Computing dependencies for py-pyobjc ---> Fetching py-pyobjc Error: Target org.macports.fetch returned: PyObjC 1.4 is for Mac OS X 10.4 and lower. On 10.5, use py-pyobjc2 instead. Log for py-pyobjc is at: /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_ports_python_py-pyobjc/main.log Error: Status 1 encountered during processing. It says to use py-objc2 instead, so I do so and get this error: sudo port install py-pyobjc2 Error: Target org.macports.activate returned: Image error: /opt/local/lib/python2.4/site-packages/modulegraph/__init__.py is being used by the active py-modulegraph port. Please deactivate this port first, or use 'port -f activate py-modulegraph-devel' to force the activation. Log for py-modulegraph-devel is at: /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_ports_python_py-modulegraph-devel/main.log Error: The following dependencies failed to build: py-py2app-devel py-modulegraph-devel Error: Status 1 encountered during processing. To report a bug, see <http://guide.macports.org/#project.tickets> I attempted to correct the issue by entering the following: port -f activate py-modulegraph-devel But it returned this error: Warning: Failed to open Portfile from registry for py-modulegraph-devel @0.7.2_0 ---> Activating py-modulegraph-devel Error: port activate failed: sqlite error: attempt to write a readonly database (8) This is as far as I have got with resolving this issue so far. All help and guidance will be greatly appreciated. Kevin Rapley

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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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2to3 conversion
by Zubin Mithra July 1, 2011

July 1, 2011

Hey everyone, I was running 2to3 on a particular file and I got the following traceback( http://paste.pocoo.org/show/223468/). The file which I was attempting to convert can be viewed here( http://paste.pocoo.org/show/223469/). Any pointers on what needs to be done? Thanks in advance, Zubin

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sftp get single file
by Matt Herzog June 22, 2011

June 22, 2011

Hello All. I need to use paramiko to sftp get a single file from a remote server. The remote file's base name will be today's date (%Y%m%d) dot tab. I need help joining the today with the .tab extension. Do I need globbing? example: 20090716.tab #!/usr/bin/env python import paramiko import glob import os import time hostname = 'sftp.booboo.com' port = 22 username = 'booboo' password = '07N4219?' # glob_pattern='*.tab' today = time.strftime("%Y%m%d") remotepath = today.tab localpath = '/home/data/text' if __name__ == "__main__": t = paramiko.Transport((hostname, port)) t.connect(username=username, password=password) sftp = paramiko.SFTPClient.from_transport(t) sftp.get(remotepath, localpath) t.close() -- I fear you speak upon the rack, Where men enforced do speak anything. - William Shakespeare

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Plotting a Linear Equation
by Corey Richardson April 21, 2011

April 21, 2011

Hello tutors. Probably the wrong mailing list, but someone might know. I want to use matplotlib (or similar) to plot an equation in slope-intercept (y=mx+b) or standard form (Ax + By = C). As far as I've read and tested, you can only plot with a series of points. I could make two points out of those manually, but I was wondering if anyone knew of an easier way. Thanks.

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Decoding from strange symbols
by Oleg Oltar Feb. 20, 2011

Feb. 20, 2011

Hi, I am trying to decode a string I took from file: file = open ("./Downloads/lamp-post.csv", 'r') data = file.readlines() data[0] '\xff\xfeK\x00e\x00y\x00w\x00o\x00r\x00d\x00\t\x00C\x00o\x00m\x00p\x00e\x00t\x00i\x00t\x00i\x00o\x00n\x00\t\x00G\x00l\x00o\x00b\x00a\x00l\x00 \x00M\x00o\x00n\x00t\x00h\x00l\x00y\x00 \x00S\x00e\x00a\x00r\x00c\x00h\x00e\x00s\x00\t\x00D\x00e\x00c\x00 \x002\x000\x001\x000\x00\t\x00N\x00o\x00v\x00 \x002\x000\x001\x000\x00\t\x00O\x00c\x00t\x00 \x002\x000\x001\x000\x00\t\x00S\x00e\x00p\x00 \x002\x000\x001\x000\x00\t\x00A\x00u\x00g\x00 \x002\x000\x001\x000\x00\t\x00J\x00u\x00l\x00 \x002\x000\x001\x000\x00\t\x00J\x00u\x00n\x00 \x002\x000\x001\x000\x00\t\x00M\x00a\x00y\x00 \x002\x000\x001\x000\x00\t\x00A\x00p\x00r\x00 \x002\x000\x001\x000\x00\t\x00M\x00a\x00r\x00 \x002\x000\x001\x000\x00\t\x00F\x00e\x00b\x00 \x002\x000\x001\x000\x00\t\x00J\x00a\x00n\x00 \x002\x000\x001\x000\x00\t\x00A\x00d\x00 \x00s\x00h\x00a\x00r\x00e\x00\t\x00S\x00e\x00a\x00r\x00c\x00h\x00 \x00s\x00h\x00a\x00r\x00e\x00\t\x00E\x00s\x00t\x00i\x00m\x00a\x00t\x00e\x00d\x00 \x00A\x00v\x00g\x00.\x00 \x00C\x00P\x00C\x00\t\x00E\x00x\x00t\x00r\x00a\x00c\x00t\x00e\x00d\x00 \x00F\x00r\x00o\x00m\x00 \x00W\x00e\x00b\x00 \x00P\x00a\x00g\x00e\x00\t\x00L\x00o\x00c\x00a\x00l\x00 \x00M\x00o\x00n\x00t\x00h\x00l\x00y\x00 \x00S\x00e\x00a\x00r\x00c\x00h\x00e\x00s\x00\n' How do I convert this to something human readable?

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Re: [Tutor] vim as a python editor
by Paul Griffiths Feb. 8, 2011

Feb. 8, 2011

On 5 January 2011 11:54, Sean Carolan <scarolan(a)gmail.com> wrote: > > How have those of you who use vim configured it? I have looked > > on the web but got a bit confused by the advice and options. > > My setup includes: > > autoindent turned on at 4 spaces > ftplugin for "folding" functions like eclipse (this is my favorite! > you just push f to expand a function) > minibufexplorer for opening multiple files > taglist for jumping around your code to different functions (needs > exuberant ctags) > > Here are some instructions for setting most of these up: > > http://dancingpenguinsoflight.com/2009/02/python-and-vim-make-your-own-ide/ > Thank you Sean for the above link, and to everyone else who replied. There is obviously a lot that can be done with vim, but I will take your advice and build up these skills gradually and try to concentrate on learning python! I've learned that: - gvim may suit me better than vim - a tabbed console is not as good as having a separate window for vim, the python interpreter and the shell. (thank you Alan) - re-configuring the Caps Lock to be an extra Esc saves time - I must learn how to 'fold' functions

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decimal module and precision
by Richard D. Moores Feb. 2, 2011

Feb. 2, 2011

Python 3.1 The decimal module continues to puzzle me from time to time. Here's one of those. I want to use Alex Martelli's factory function as much as possible. Turns out it has a problem with precision in addition and multiplication. ========================================= from decimal import Decimal as D import decimal #Alex Martelli's factory function from 'Python in a Nutshell', 2nd ed., p.373 def d(x): return decimal.Decimal(str(x)) decimal.getcontext().prec = 55 print('power') a = D('123.2345274523452345235432452345')**D('2.3') a2 = d(123.2345274523452345235432452345)**d(2.3) print('a =', a) print('a2 =', a2) print() print('addition') x = D('123.2345274523452345235432452345')+D('2.3') x2 = d(123.2345274523452345235432452345)+d(2.3) print('x =', x) print('x2 =', x2) print() print('division') y = D('123.2345274523452345235432452345')/D('2.3') y2 = d(123.2345274523452345235432452345)/d(2.3) print('y =', y) print('y2 =', y2) print() print('multiplication') z = D('123.2345274523452345235432452345')*D('2.3') z2 = d(123.2345274523452345235432452345)*d(2.3) print('z =', z) print('z2 =', z2) ================================= =============Output================ power a = 64370.15122802469152726635110412345417588163863981991324 a2 = 64370.15122760993409213289215777394902129746619501742003 addition x = 125.5345274523452345235432452345 x2 = 125.534527452 division y = 53.58022932710662370588836749326086956521739130434782609 y2 = 53.58022932695652173913043478260869565217391304347826087 multiplication z = 283.43941314039403940414946403935 z2 = 283.4394131396 =========end of Output======================= Why in the world does precision not work for addition and multiplication (see x2 and z2)? Thanks, Dick Moores

4 6

search list with regex
by Elwin Estle Jan. 31, 2011

Jan. 31, 2011

Tcl's list search command has the option to search for a list element that matches a given regex. Is there something similar in python? If not, it seems like it should be fairly trivial for me to write my own (just wondering if I would be re-inventing the wheel).

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