🌐 Mailman 3 March 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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Converting a numpy matrix to a numpy array
by David Crisp April 4, 2011

April 4, 2011

Hello, I have a very simple question / problem I need answered. The problem is imnot entirely sure of the correct terminology and langauge to use to describe it. (One of the reasons im using this miling list) I have a 2d matrix representing the X the Y and the Z value of a point. I wish to convert that matrix to an array. What is a good way of doing so? Eg: Matrix 012345 0xooooo 1xooooo 2oxxxxx 3oooooo 4ooooox 5ooooox I want to convert that to a 2d array which looks like: 0,0,x 0,1,o 0,2,o 0,3,o 0,4,o 0,5,o ....... 5,4,o 5,5,o I am pretty sure it is simple. I'm just having a brain fade. Regards, David

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(no subject)
by "Andrés Chandía" April 3, 2011

April 3, 2011

I'm new to this list, so hello everybody!. The stuff: I'm working with regexps and this is my line: contents = re.sub("<u>l<\/u>", "le" ,contents) in perl there is a way to reference previous registers, i.e. $text =~ s/<u>(l|L|n|N)<\/u>/$1e/g; So I'm looking for the way to do it in python, obviously this does not works: contents = re.sub("<u>(l|L|n|N)<\/u>", "$1e", contents) Thanks _______________________ andrés chandía P No imprima innecesariamente. ¡Cuide el medio ambiente!

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Run application from MS-DOS with sys.argv
by Susana Iraiis Delgado Rodriguez April 1, 2011

April 1, 2011

Hello List: I developed a script to walk through a specific directory in my PC and look for files with the same extension (.shp). I want the user to enter from MS-DOS and write the the directory, file extension and csv filename. My script reads the arguments from Windows console, but when I opened the txt file and csv file I noticed that isn't walking through all the root I wrote in MS-DOS. This is my module: import os, csv, time, socket, sys from osgeo import ogr,gdal,osr #This should be the order for the arguments('csv_args.py [root] [file_extension] [csv filename]') #The user is typing python csv_args.py C:\ .shp csv.csv directorio = sys.argv[1] extension = sys.argv[2] csv_salida = sys.argv[3] if len(sys.argv) == 4: print 'Iniciando...' gdal.AllRegister() file_list = [] folders = None for root, folders, files in os.walk(directorio): file_list.extend(os.path.join(root,fi) for fi in files if fi.endswith(extension)) f = open(csv_salida, 'wb') log = open ('errores.txt','w') writer = csv.writer(f) ruta = 'Ruta' archivo = 'archivo' x_min = 'x_min' x_max = 'x_max' y_min = 'y_min' y_max = 'y_max' geometria = 'geometria' num_elem = 'num_elem' prj = '.prj' proyeccion = 'proyeccion' fecha = 'fecha_modificacion' maq = 'maquina_host' usu = 'usuario' campos = [ruta,archivo,x_min,x_max,y_min,y_max,geometria,num_elem,prj,proyeccion,fecha,maq,usu] writer.writerow(campos) for row, filepath in enumerate(file_list, start=1): (ruta, filename) = os.path.split(filepath) shapeData = ogr.Open(filepath) shp = 'Error al abrir el archivo' +filepath if shapeData is None: print shp log.write(shp+"\n") else: layer = shapeData.GetLayer() feature = layer.GetNextFeature() x_y = layer.GetExtent() x1 = x_y[0] x2 = x_y[1] y1 = x_y[2] y2 = x_y[3] defn = layer.GetLayerDefn() geo = defn.GetGeomType() cuenta = layer.GetFeatureCount() proy = layer.GetSpatialRef() prjtext = ''+str(proy)+'' n = os.path.splitext(filepath) p = n[0]+'.prj' shx = n[0]+'.shx' dbf = n[0]+'.dbf' filepath = ''+filepath+'' filename = ''+filename+'' t = time.strftime("%m/%d/%Y %I:%M:%S %p",time.localtime(os.path.getmtime(filepath))) modificacion = ''+t+'' usuario = os.environ.get("USERNAME") user = ''+usuario+'' host = socket.gethostname() maquina = ''+host+'' if os.path.exists(shx): print 'El archivo ' +shx +' existe' else: og.write('No existe el archivo ' +shx+"\n") if os.path.exists(dbf): print 'El archivo ' +dbf +' existe' else: log.write('No existe el archivo ' +dbf+"\n") if os.path.exists(p): aRow= [ filepath, filename, x1, x2, y1, y2, geo, cuenta, 1, prjtext, modificacion, maquina, user] writer.writerow(aRow) else: aRow1= [ filepath, filename, x1, x2, y1, y2, geo, cuenta, 0, prjtext, modificacion, maquina, user] writer.writerow(aRow1) log.close() f.close() print "El archivo esta listo" else: print "Tus argumentos no son correctos"

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Importing sub modules
by Prasad, Ramit April 1, 2011

April 1, 2011

Hi everyone, I was wondering if there is a difference in >>>import os >>>os.path.join(string1,string2) AND >>>import os.path >>>os.path.join(string1,string2) The only difference that I could think of is if the os module does not get loaded on the second example. I am not sure if it does. Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities.

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