🌐 Mailman 3 July 2009 - 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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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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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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Tracking time
by Michael Key Jan. 6, 2010

Jan. 6, 2010

I am trying to develop a project tracking program that would allow you to track hours and minutes spent on several different projects and store he data in a database for printing. Any help would be appreciated. Mike

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Learning Python
by Fred P Dec. 13, 2009

Dec. 13, 2009

Hey Everyone, I am completely new at python, but not new to programming or scripting. I have a couple of years of LUA scripting experience, about a year of C++ classes, and used to be very efficient at c-shell scripting in unix. My question for you guys: 1) How do I get Started? 2) Recommend any specific Books? 3) Any online tutors/ forums that would benefit a newbie 4) Any online classes that teach python? I have taken online c++ courses, and found them helpful. I was hoping to find something for python. My main objective is to write scripts for the following type of applications File management, file copies/syncs/ compares Text manipulation - like parsing text files to replace or augment specific values Integration into current applications to write redundant routines and maybe some day plugins I am not even sure what else, but I do know that every time i think of something that we need at work, other people say, "That would be a good task for a python script" and I would eventually like to be able to do something about that. Thanks Fred

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mnemonics to better learn Python
by David July 31, 2009

July 31, 2009

Dear List, in order to memorize which Python sequences are mutable or immutable, I focused on the SHAPE of the brackets that are associated with each type of sequence. For instance, a *list* is characterised by square brackets, []. My mnemonic device to memorize that lists are mutable is this: "the brackets have sharp edges, they could be trimmed, taking their edges off". The same thing happens with *dictionaries* (which, okay, are not sequences). Anyway, their brackets, {}, have sharp edges, hence they are mutable. *Tuples*, in turn, have perfectly 'round' brackets, (), and these brackets obviously can't be improved upon by taking anything off them. Hence: tuples are immutable. That leaves us with *strings*, which are also not mutable. Here we have no brackets, and this particular mnemonic device breaks down. What I am interested in is finding out whether you use similar techniques, and if so, which ones? How, for examples, do you make sense of all those special characters that make regular expressions powerful? Do you rely on rote learning, or do you employ some other technique? I reckon that if we could come up with some tips and techniques as to how to uncloud the thick information fog that any beginning programmer has to wade through, the very first steps in learning Python could be made more easy. What insights can you share? Curious, David

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concerning help() function
by David July 31, 2009

July 31, 2009

Dear Tutors, whenever I make use of the help() function, I have a good chance of getting an error. I have not yet understood this tool very well. Take the modules operator and random as examples. The former is built-in, the latter not. Do I wish to see the help files, I have to use a different syntax: help(random) help('operator') I figured this by trial and error, and I am keen to find out when the help() function is to be supplied with a string, and when no '' is required. It certainly does not seem intuitive to me! Many thanks, David

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Re: [Tutor] How to use Python 2.6 with IDLE?
by ALAN GAULD July 31, 2009

July 31, 2009

> > What I do for these things is create a shortcut which specifies the full > > path to the interpreter and to the pyw file. I also set the working foldeer > > to wherever is most appropriate - usually my project folder. That's fairly > > bulletproof in my experience! > > Alan, here's what have now to call Ulipad: the shortcut shown in the > attached image. It opens Ulipad, but a Ulipad that uses 2.51, not 2.62 So edit the Target field of the shortcut to say: E:\Python26\pythonw.exe E:\Programs\Ulipad37\ulipad.pyw Or whatever combination of interpreter and editor you want. In other words explicitly specify both the interpreter and the file rather than relying on Windows file associations. And if that fails to work, the lasst resort is to write a batch file that calls the right file with the rigt interpreter and then create a shortcut to that! > at E:\Python26\pythonw.exe (is that what you mean by the > interpreter?). Yes that is the interpreter. Alan G.

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flag to call methods on objects?
by prasad rao July 31, 2009

July 31, 2009

hello I removed the bugs.But still getting error report. >>import mcript Traceback (most recent call last): File "<pyshell#6>", line 1, in <module> import mcript File "C:\Python26\mcript.py", line 78, in <module> a.main() File "C:\Python26\mcript.py", line 58, in main nl=__compress(__digi(__lengthen(line.strip())))+'\n' NameError: global name '_Cripto__compress' is not defined There is no string '_Cripto__compress' any whare in the script. So I dont know what corrections Ineed to make in the script. I am giving my code below again again . <code> #! usr/bin/env python import ast,random,os,zlib,string key=5 class Cripto(object): def __init__(self,afile): self.afile=afile def __digi(self,astring): y=[] for x in astring: y.append(ord(x)) y=str(y) return y def __undigi(self,astring): alist=ast.literal_eval(astring) y=[] for x in alist: y.append(chr(x)) astring=''.join(y) return astring def __gen_string(self): s='' nl=random.sample(string.ascii_letters,key) for x in nl:s+=x return s def __lengthen(self,astring): s=list(astring) ns='' for x in s: ns+=x ns+=gen_string() return ns def __shorten(self,astring): s=list(astring) ns='' for x in range(0,len(s),key+1): ns+=s[x] return ns def __compress(self,astring): astring=zlib.compress(astring) return astring def __decompress(self,astring): astring=zlib.decompress(astring) return astring def main(self): sorce=open(self.afile,'r') data=(sorce.readlines()) dest=open((os.path.split(self.afile)[0]+os.sep+'temp'),'w') if (data[0]).strip()=='flag1': ns='flag0\n' data=data[1:] for line in data: nl= __compress(__digi(__lengthen(line.strip())))+'\n' ns+=nl dest.write(ns) elif data[0].strip()=='flag0': ns='flag1\n' data=data[1:] for line in data: nl= __shorten((__undigi(__decompress(line.strip()))))+'\n' ns+=nl dest.write(ns) else:prind 'File does not begin with the flag' sorce.close() dest.close() os.remove(self.afile) os.rename((os.path.split(self.afile)[0]+os.sep+'temp'),self.afile) #======== a=Cripto('C:/pp.txt') a.main() <\code>

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