🌐 Mailman 3 August 2010 - 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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cx_Oracle help
by Greg Lindstrom Jan. 6, 2011

Jan. 6, 2011

Hello, I'm trying to help out a friend and am stumped. Can you help me out? Thanks, --greg - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I will briefly explain the problem I am facing. I am using Oracle 9.2, Python 2.5 and I installed cx_Oracle- 4.3.1-win32-9i-py25 in Python. From python I tried following : >>> import cx_Oracle >>> myDsn = cx_Oracle.makedsn('ISCN47',1521,'AUBDBS01') >>> CONN = cx_Oracle.connect(myusr, mypwd, myDsn) Traceback (most recent call last): File "<pyshell#4>", line 1, in <module> conn = cx_Oracle.Connection('scott','tiger',myDsn) RuntimeError: Unable to acquire Oracle environment handle I have set the below environment variables too NLS_LANG: <snip>.WE8MSWIN1252 ORACLE_HOME: D:\Tools\oracle\ora92 ORACLE_SID: AUBDBS01 PYTHON_HOME: d:\Utility\Python25 PYTHONPATH: %PYTHON_HOME%\lib;%PYTHON_HOME%\DLLs;%PYTHON_HOME%\Lib\site-packages;%ORACLE_HOME%\bin LD_LIBRARY_PATH: %LD_LIBRARY_PATH%;D:\Tools\oracle\ora92\lib Not getting any idea where I am wrong? Regards, Kishore

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What Design Pattern for Document class (NOT URGENT)
by Karim Sept. 12, 2010

Sept. 12, 2010

Hello All, I want to build some classes by optimizing their design. But I want to keep quite 'simples'. I have a XML document which represents let's say some rules (id, description, value). My first idea is to create an *docrules* class which holds my document. This class will use 2 other instances from 2 respectives classes reader and writer. The main method of reader is get(). The main method of writer is write(). To resume I have: ------------------------------ ----------------------- - docrules ----------------------------------- reader - ------------------------------ ----------------------- - filename - - file - - ---------------------------- ----------------------- - - - get() - - ------- ----------------------- ------------------------------ - - - ------------------------ ------------------------------- writer - ------------------------ - file - ------------------------ - write() - ------------------------ The *docrules* will do the parsing (*xml.etree* very effective) and create the reader and the writer instance. I want to create 2 others classes (or more) more specific which have more the knowledge about the XML documents structures. *SpecificRuleReader*, *SpecificRuleWriter* which are deriving resp. from Reader and Writer which hold resp. *getSpecificRules*() (use of get('/tag1/tag2/tag3/specificTagRules') and a* writeSpecificRules*(): ----------------------------- --------------------------------- reader writer ----------------------------- --------------------------------- ^ ^ | | ------------------------------- ----------------------------------- *SpecificRuleReader* *SpecificRulesWriter* ------------------------------- ----------------------------------- *getSpecificRules*() *writeSpecificRules()* -------------------------------- -------------------------------------- My purpose is to separate as far as possible XML representation from core classes. I will have certainly more SpecificrulesReader/Writer classes becauses the document is huge and several discipline rules will be adressed. I don't want necessarily have 2 big classes which know everything about XML document because I will have too many methods. So, for if anybody has this kind of experience or any design pattern idea, I will be enchanté. Regards Karim

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Function object
by Daniel Sept. 12, 2010

Sept. 12, 2010

Hello again, seems like in my journey to learn Python I have stumbled into another problem regarding understanding a concept- function object. As I said, I do not understand what a function object is, what it does, and what can I do with it? I'm currently reading Think python, but the book is not clear for me. Python is my first programming language. Please, can you give me some examples and if it is possible can you explain in a more beginner orientated way? also if someone has a minute I'm available on google chat, if it's more convenient to explain this way. Thanks so much and I hope I didn't disturb anyone with my questions. I know you probably get this question and others a lot. But please understand, my goal with this email is not to make you angry or something like that, I really like programming and what to learn it but as a beginner I find some concepts hard to understand just by reading.

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NLTK needs YAML?
by Michael Scharf Sept. 2, 2010

Sept. 2, 2010

Dear Friends, I'm new to the list, and new to Python. The last time I've tried anything like the below was 20 years ago on a NeXT machine, and I had no clue what I was doing then, either. I've gotten IDLE up and have done some hello worlding. I am now trying to get the NLTK working on my new iMac running OS X 10.6.3. The Python version I have up is 2.6.5. (There may be a slightly older pre-install with faulty IDLE lingering somewhere on the machine.) I've installed Macports, and through it I installed NLTK by saying $ sudo port install nltk which worked. But when, in a Python session, I try to >>> import nltk Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named nltk is what I get. Macports says if that happens that I should $ cd /tmp/nltk-installer which works. And that I should then $ sudo python setup.py install Traceback (most recent call last): File "setup.py", line 13, in <module> import nltk File "/private/tmp/nltk-installer/nltk/__init__.py", line 92, in <module> from yamltags import * File "/private/tmp/nltk-installer/nltk/yamltags.py", line 1, in <module> import yaml ImportError: No module named yaml So I did this: $ port search yaml And got: libyaml @0.1.3 (devel) A YAML Parser. p5-data-phrasebook-loader-yaml @0.09 (perl) Abstract your queries ... with YAML! p5-test-yaml-meta @0.15 (perl) Validation of the META.yml file in a distribution. p5-test-yaml-valid @0.04 (perl) Test for valid YAML p5-yaml @0.68 (perl) YAML loader/dumper module p5-yaml-libyaml @0.32 (perl) Perl YAML Serialization using XS and libyaml p5-yaml-syck @0.99 (perl) A fast, lightweight YAML loader and dumper p5-yaml-tiny @1.41 (perl) Read/Write YAML files with as little code as possible py-yaml @3.05 (python, devel) YAML 1.1 parser and emitter for Python py25-yaml @3.08 (python, devel) YAML 1.1 parser and emitter for Python py26-yaml @3.08 (python, devel) YAML 1.1 parser and emitter for Python rb-bee @0.5.1 (ruby, devel) Bee is a build tool running YAML files syck @0.55 (textproc, devel) An extension for reading and writing YAML yaml-mode.el @0.0.3 (editors) An emacs major mode for editing yaml files. Found 14 ports. So I then did: $ sudo port install py26-yaml ---> Computing dependencies for py26-yaml ---> Cleaning py26-yaml closed and re-opened the terminal, and tried it all again. But I still get the same ImportError: No module named yaml So my question is: do I really not have what I need here? Or is it a question of something not finding something that's there? Maybe I'm using the wrong name somewhere? Or?? Many thanks, Mike S.

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__new__ over __init__
by Payal Sept. 2, 2010

Sept. 2, 2010

Hi all, Can someone please give a very simple example of using __new__ wherein __init__ cannot be used? With warm regards, -Payal --

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