🌐 Mailman 3 March 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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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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Remote access from Windows PC to a Linux box
by Mike Baker April 21, 2010

April 21, 2010

Hi, I'm trying to connect to a Linux box from my Windows machine and execute a series of commands - (ls, pwd, cat 'somefile', etc...). I'm using Putty to do the ssh and have set up with Putty's Pagent agent to allow me to enter a passphrase once per session to handle security keys between the two boxes (so, no passwords needed for my remote scripts). I have code that will give me a remote prompt on the Linux machine where I can manually enter commands. This works great, but I want a script to always execute the same series of commands without having to do so manually. I also have code that will execute a single command like cat a file and write the ouput to a new file. However, when I try to use the communicate object in subprocess, my window hangs. Here is my working code: # module name data_collect.y # import subprocess def simp_tst0(s_name): # Opens a remote connection to "s_name and gives a prompt. # Works great for executing linux commands. # Does not exit gracefully when you type exit. The python # prompt hangs when it gets to the r.communicate command # cmmnd_0="C:\\Progra~1\\putty\\plink %s" % s_name r = subprocess.Popen("%s" % cmmnd_0,shell=False) (r_stdout, r_stderr) = r.communicate("dir") #status=r.poll() #Locks up if you try to poll here print r_stdout return r def cat_remote(s_name, file2cat): # This simple test file opens a remote connection to "s_name", does a cat on # file "file2cat" and writes the cat to an output file (out2.txt). cmmnd_2="C:\\Progra~1\\putty\\plink %s cat %s" % (s_name, file2cat) q = subprocess.Popen("%s" % cmmnd_2, stdout=open('out2.txt','w')) def simp_tst3(s_name): # Runs the initial subprocess.Popen command - creates proc. # Hangs when you try to use proc.communicate proc = subprocess.Popen(['C:\\Progra~1\\putty\\plink','Sula'], shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, ) #Either of the next two commands cause window to hang #proc.stdin.write("dir") #(stdout_value, stderr_value) = proc.communicate(input="dir")[0] return proc Thanks, Mike

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Introduction to modelling with Python
by AG April 15, 2010

April 15, 2010

Hi List I apologise in advance for the vagueness of this query, but I am looking for a decent modern introduction to modelling using Python. Specifically, I want something that is a good introduction (i.e. doesn't expect one to already be a maths/ statistics or a programming guru) and that has an ecology/ environmental science orientation. The latter is desirable but not essential, as I suspect that once one understands the process of data abstraction and the other steps involved in modelling processes and scenarios, the thinking and skill sets are likely transferable. However, if my assumption about this is incorrect, please let me know. If anyone knows of any resource (book or on-line) with a Python bent, please let me know. I am preparing to begin applications to Ph.D. programs and most of what I am interested in doing requires some knowledge of modelling and Python also seems to be widely accepted as a programming language, so I am happy with that as I am in the process of teaching myself Python anyway. Thanks for any help, advice, etc. Cheers AG

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simple search and replace...
by Spencer Parker April 3, 2010

April 3, 2010

I am writing a script to help me add line breaks at certain segments of HL7 messages. Not sure if anyone here is familiar with what an HL7 message is or not. We receive them out of our database with all the segments on one line. I am trying to write a script to allow me to separate them at a certain point and add a line break. A message would look like this: MSH|~^\&|SCW|SMED|COR||20100305123742||ORU^R01|100305123742891|P|2.2|||||||PID|||001109660||TEST^Man||19920519|M||||||||||00055254593|699-63-1152||||||||||| What I want to do is where it says, PID, is add a line break right before that to knock it down to a new line. I currently have a dictionary that contains all of the segments and am wondering what the best way to approach this is. I thought about a regular expression...but...I don't think that is the best way. The basic file i/o I know...it is the search and carriage I need help with. Any ideas? I was thinking of using a 'for i in segments' statement to run through the dictionary of items.

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what's wrong in my command?
by Shurui Liu (Aaron Liu) April 1, 2010

April 1, 2010

# geek_translator3.py # Pickle import pickle # Open Dictionary geekfile = open('geekdictionary3.txt', 'r+') new_geeks = pickle.load(geekfile) geekterms = new_geeks.keys() geekterms.sort() # start choice = None while choice != "0": print \ """ Geek Translator 0 - Quit 1 - Look Up a Geek Term 2 - Add a Geek Term 3 - Redefine a Geek Term 4 - Delete a Geek Term 5 - List of Terms """ choice = raw_input("Choice: ") print # exit if choice == "0": print "Good-bye." # get a definition elif choice == "1": term = raw_input("What term do you want me to translate?: ") if term in new_geeks: definition = new_geeks[term] print "\n", term, "means", definition else: print "\nSorry, I don't know", term # add a term-definition pair elif choice == "2": term = raw_input("What term do you want me to add?: ") if term not in new_geeks: definition = raw_input("\nWhat's the definition?: ") new_geeks[term] = definition geekterms.append(term) geekterms.sort() print "\n", term, "has been added." else: print "\nThat term already exists! Try redefining it." # redefine an existing term elif choice == "3": term = raw_input("What term do you want me to redefine?: ") if term in new_geeks: definition = raw_input("What's the new definition?: ") new_geeks[term] = definition print "\n", term, "has been redefined." else: print "\nThat term doesn't exist! Try adding it." # delete a term-definition pair elif choice == "4": term = raw_input("What term do you want me to delete?: ") if term in new_geeks: del new_geeks[term] geekterms.remove(term) print "\nOkay, I deleted", term else: print "\nI can't do that!", term, "doesn't exist in the dictionary." # list of terms elif choice == "5": print geekterms # some unknown choice else: print "\nSorry, but", choice, "isn't a valid choice." # geek speak link print "\tTo learn to speak geek visit" print "\n\t\thttp://www.youtube.com/watch?v=7BpsXZpAARk" # 133t speak links print "\n\n\tTo learn to 1337 speak visit" print "\n\t\thttp://linuxreviews.org/howtos/l33t/" print "\n\t\t\t\tor" print "\n\t\thttp://textozor.com/hacker-text/" # save dictionary pickle.dump(ldict, open('geekdictionary.txt', 'r+')) # close file geekfile.close() raw_input("\n\nPress the enter key to exit.") When I run it, the system gave me the feedback below: Traceback (most recent call last): File "geek_translator3.py", line 4, in <module> import pickle File "/usr/local/lib/python2.5/pickle.py", line 13, in <module> AttributeError: 'module' object has no attribute 'dump' I don't understand, I don't write anything about pickle.py, why it mentioned? what's wrong with "import pickle"? I read many examples online whose has "import pickle", they all run very well. Thank you! -- Shurui Liu (Aaron Liu) Computer Science & Engineering Technology University of Toledo

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Script Feedback
by Damon Timm March 31, 2010

March 31, 2010

As a self-taught Python user I am still looking for insight on the most pythonic and programmatically-friendly way of accomplishing a given task. In this case, I have written a script that will perform a “clean bzip2″ of a directory (or directories). Mac OS X (via AFP and netatalk, in my case) tends leaves a bunch of ugly files/directories hanging around and I would rather not include them in my compressed tar file. In writing the script, though, I ran into some questions and I am not sure what the recommended approach would be. The script works, as it is, but I feel its a little hacked together and also a little limited in its application. There is something to be said for programs that "just work" (this does) but I want to take it a little further as an educational endeavor and would like it to appear robust, future-thinking, and pythonic. My initial questions are: 1. Is there a better way to implement a --quiet flag? 2. I am not very clear on the use of Exceptions (or even if I am using it in a good way here) — is what I have done the right approach? 3. Finally, in general: any feedback on how to improve this? (I am thinking, just now, that the script is only suitable for a command line usage, and couldn’t be imported by another script, for example.) Any feedback is greatly appreciated. Writing a script like this is a good learning tool (for me, at least). I have posted this email online if you want to see the script with pretty code formatting: http://blog.damontimm.com/python-script-clean-bzip/ Thanks for any insight you may provide. Damon Script follows ************************ #! /usr/bin/env python '''Script to perform a "clean" bzip2 on a directory (or directories). Removes extraneous files that are created by Apple/AFP/netatalk before compressing. ''' import os import tarfile from optparse import OptionParser IGNORE_DIRS = ( '.AppleDouble', ) IGNORE_FILES = ('.DS_Store', ) class DestinationTarFileExists(Exception): '''If the destination tar.bz2 file already exists.''' def ignore_walk(directory): '''Ignore defined files and directories when doing the walk.''' for dirpath, dirnames, filenames in os.walk(directory): dirnames[:] = [ dn for dn in dirnames if dn not in IGNORE_DIRS ] filenames[:] = [ fn for fn in filenames if fn not in IGNORE_FILES ] yield dirpath, dirnames, filenames def tar_bzip2_directories(directories): for directory in directories: file_name = '-'.join(directory.split(' ')) tar_name = file_name.replace('/','').lower() + ".tar.bz2" if os.path.exists(tar_name): raise DestinationTarFileExists() if not options.quiet: print 'Compressing files into: ' + tar_name tar = tarfile.open(tar_name, 'w:bz2') for dirpath, dirnames, filenames in ignore_walk(directory): for file in filenames: if not options.quiet: print os.path.join(dirpath, file) tar.add(os.path.join(dirpath, file)) tar.close() if __name__ == "__main__": parser = OptionParser(usage="%prog [options: -q ] [directory]") parser.add_option("-q", "--quiet", action="store_true", dest="quiet") options, args = parser.parse_args() directories = [] for arg in args: if os.path.isdir(arg): directories.append(arg) else: print "Ingoring: %s (it's not a directory)." % arg try: tar_bzip2_directories(directories) except DestinationTarFileExists: print "A tar file already exists this this directory name." print "Move or rename it and try again."

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Re: [Tutor] help
by bob gailer March 31, 2010

March 31, 2010

Thank you for specifics. Please always reply-all so a copy goes to the list. On 3/30/2010 3:41 PM, Oshan Modi wrote: > > I have windows 7 (ultimate), python 2.6.3... > when i try to run the file echoinput.py Please post a copy of this file. > it doesnt respond to the request Actually you should say "I don't get the result I expected." Since there is no Windows error message we must conclude that the program ran. > .. and here's what the output is.. > > Microsoft Windows [Version 6.1.7600] > Copyright (c) 2009 Microsoft Corporation. All rights reserved. > > C:\Users\doggie>python echoinput.py > > C:\Users\doggie> > > > > > and i have a couple of more files in that folder and when i try to run > them this is what the error looks like.. > > Microsoft Windows [Version 6.1.7600] > Copyright (c) 2009 Microsoft Corporation. All rights reserved. > > C:\Users\doggie>python class.py > python: can't open file 'class.py': [Errno 2] No such file or directory > > C:\Users\doggie> The message seems pretty self-evident. There is no file named class.py in c:\Users\doggie. > the list does show up when i use IDLE and it is like this > ****************************** > ********************************** > > IDLE 2.6.3 > >>> import sys > >>> for i in sys.path: > print i > > > C:\Python26\Lib\idlelib > C:\Windows\system32\python26.zip > C:\Python26\DLLs > C:\Python26\lib > C:\Python26\lib\plat-win > C:\Python26\lib\lib-tk > C:\Python26 > C:\Python26\lib\site-packages > -- Bob Gailer 919-636-4239 Chapel Hill NC

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