🌐 Mailman 3 May 2006 - Python-list - python.org

Re: Strange behavior with iterables - is this a bug?
by akameswaran＠gmail.com May 31, 2006

May 31, 2006

My original concern and reason for goint the iterator/generator route was exactly for large large lists :) Unnecessary in this example, but exactly what I was exploring. I wouldn't be using list comprehension for generating the permutiations. Where all this came from was creating a generator/iterator to handle very large permutations. Gary Herron wrote: > akameswaran(a)gmail.com wrote: > > >Gary Herron wrote: > > > > > >>List comprehension is a great shortcut, but when the shortcut starts > >>causing trouble, better to go with the old ways. You need to reopen each > >>file each time you want to iterate through it. You should be able to > >>understand the difference between these two bits of code. > >> > >>The first bit opens each file but uses (two of them) multiple times. > >>Reading from a file at EOF returns an empty sequence. > >> > >>The second bit opened the file each time you want to reuse it. That > >>works correctly. > >> > >>And that suggest the third bit of correctly working code which uses list > >>comprehension. > >> > >># Fails because files are opened once but reused > >>f1 = open('word1.txt') > >>f2 = open('word2.txt') > >>f3 = open('word3.txt') > >>for i1 in f1: > >> for i2 in f2: > >> for i3 in f3: > >> print (i1.strip(),i2.strip(),i3.strip()) > >> > >>and > >> > >># Works because files are reopened for each reuse: > >>f1 = open('word1.txt') > >>for i1 in f1: > >>f2 = open('word2.txt') > >>for i2 in f2: > >>f3 = open('word3.txt') > >>for i3 in f3: > >>print (i1.strip(),i2.strip(),i3.strip()) > >> > >>and > >> > >># Also works because files are reopened for each use: > >>print [(i1.strip(),i2.strip(),i3.strip()) > >> for i1 in open('word1.txt') > >> for i2 in open('word2.txt') > >> for i3 in open('word3.txt')] > >> > >>Hope that's clear! > >> > >>Gary Herron > >> > >> > > > > > >My original problem was with recursion. I explicitly nested it out to > >try and understand the behavior - and foolishly looked in the wrong > >spot for the problem, namely that file is not reitreable. In truth I > >was never concerned about file objects, the problem was failing with my > >own custom iterators (wich also were not reiterable) and I switched to > >file, to eliminate possible code deficiencies on my own part. I was > >simply chasing down the wrong problem. As was pointed out to me in a > >nother thread - the cleanest implementation which would allow me to use > >one copy of the file (in my example the files are identical) would be > >to use a trivial iterator class that opens the file, uses tell to track > >position and seek to set position, and returns the appropriate line for > >that instance - thus eliminating unnecessary file opens and closes. > > > > > > > I see. > > I wouldn't call "tell" and "seek" clean. Here's another suggestion. Use > l1 = open(...).readlines() > to read the whole file into a (nicely reiterable) list residing in > memory, and then iterate through the list as you wish. Only if your > files are MANY megabytes long would this be a problem with memory > consumption. (But if they were that big, you wouldn't be trying to find > all permutations would you!) > > Gary Herron

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Re: Strange behavior with iterables - is this a bug?
by akameswaran＠gmail.com May 31, 2006

May 31, 2006

Gary Herron wrote: > List comprehension is a great shortcut, but when the shortcut starts > causing trouble, better to go with the old ways. You need to reopen each > file each time you want to iterate through it. You should be able to > understand the difference between these two bits of code. > > The first bit opens each file but uses (two of them) multiple times. > Reading from a file at EOF returns an empty sequence. > > The second bit opened the file each time you want to reuse it. That > works correctly. > > And that suggest the third bit of correctly working code which uses list > comprehension. > > # Fails because files are opened once but reused > f1 = open('word1.txt') > f2 = open('word2.txt') > f3 = open('word3.txt') > for i1 in f1: > for i2 in f2: > for i3 in f3: > print (i1.strip(),i2.strip(),i3.strip()) > > and > > # Works because files are reopened for each reuse: > f1 = open('word1.txt') > for i1 in f1: > f2 = open('word2.txt') > for i2 in f2: > f3 = open('word3.txt') > for i3 in f3: > print (i1.strip(),i2.strip(),i3.strip()) > > and > > # Also works because files are reopened for each use: > print [(i1.strip(),i2.strip(),i3.strip()) > for i1 in open('word1.txt') > for i2 in open('word2.txt') > for i3 in open('word3.txt')] > > Hope that's clear! > > Gary Herron My original problem was with recursion. I explicitly nested it out to try and understand the behavior - and foolishly looked in the wrong spot for the problem, namely that file is not reitreable. In truth I was never concerned about file objects, the problem was failing with my own custom iterators (wich also were not reiterable) and I switched to file, to eliminate possible code deficiencies on my own part. I was simply chasing down the wrong problem. As was pointed out to me in a nother thread - the cleanest implementation which would allow me to use one copy of the file (in my example the files are identical) would be to use a trivial iterator class that opens the file, uses tell to track position and seek to set position, and returns the appropriate line for that instance - thus eliminating unnecessary file opens and closes.

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omniorbpy: problems sending float values
by Juergen May 31, 2006

May 31, 2006

hi, I've got a problem sending floating point values to an corba server. With other datatyes like short or string it works fine. So having this idl file : module Example{ interface User{ void setV( in float x ); }; interface Target{ void getV( out short x); }; }; I just receive zero ( -2.58265845332e-05) by sending an float to another client with the above interface. the client : ********************************************************** import sys from omniORB import CORBA import _omnipy import Example, CosNaming orb = CORBA.ORB_init(sys.argv, CORBA.ORB_ID) ior = sys.argv[1] obj = orb.string_to_object(ior) us = obj._narrow( Example.User ) if us is None: print "blabla" sys.exit(1) us.setV( 5.0 ) ********************************************************** the server : ********************************************************** import sys from omniORB import CORBA, PortableServer import CosNaming, Example, Example__POA class User_i( Example__POA.User ): def setV( self, x ): print x print type(x) y = float(x) print y print type(y) class Target_i( Example__POA.Target ): def getV( self ): return 5 orb = CORBA.ORB_init(sys.argv, CORBA.ORB_ID) poa = orb.resolve_initial_references("RootPOA") us = User_i() tg = Target_i() uo = us._this() to = tg._this() print orb.object_to_string(uo) print print orb.object_to_string(to) poaManager = poa._get_the_POAManager() poaManager.activate() orb.run() ********************************************************** does anyone have an answer to that kind of problem? I mean, it just like sending short values, or strings.

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Re: Best Python Editor
by bruno at modulix May 31, 2006

May 31, 2006

Manoj Kumar P wrote: > Hi, > > Can anyone tell me a good python editor/IDE? > It would be great if you can provide the download link also. I hate to be the one answering this, but this is *really* a FAQ - as you would have known if you had google'd this group for this. -- bruno desthuilliers python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for p in 'onurb(a)xiludom.gro'.split('@')])"

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Re: os.popen3() - how to close cmd window automatically?
by ddonato＠unisa.it May 31, 2006

May 31, 2006

> > # Script "shortcut.py" > > import os > > import webbrowser > > import win32api > > > > # open default web browser and display webbpage > > page = 'C:\\Temp\\Welcome.html' > > webbrowser.open(page) > > > > # path to application that is opened > > path = "C:\\Program Files\\ExternalApplication.exe" > > > > # get short name > > shortpath = win32api.GetShortPathName(path) > > > > # open external application > > stdin, stdout, stderr = os.popen3(shortpath) > > output = stdout.read() > > errors = stderr.read() > > stdin.close() > > stdout.close() > > stderr.close() > > print output > > print errors > > # ---------------------------------------------------------------------- > > > > > > In order to [...] In order to run this on a linux box? daniel ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.

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Way to get an array of latitude/longitude points (tuples) from a trip
by kbperry May 31, 2006

May 31, 2006

I am not sure if this is the right place for this, but I thought it was worth a shot. What I want: Enter a From: street address and a To: street address, and then specify an interval (say every half mile). Then, I click a submit button, and it gives me latitude and longitude points (in order) from the beginning of my trip to the end of my trip in 1/2 mile increments. I can't seem to find anything to simulate this, and I am not sure how to go about coding this either. BTW - I have used Yahoo geocoding service (to my delight), and while it is a good service, I don't see a way to do this unless we knew every street address in 1/2 mile increments. Are there any Python modules that would assist with dealing with latitude and longitude? Can anyone out there help?

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Re: os.popen3() - how to close cmd window automatically?
by Rony Steelandt May 31, 2006

May 31, 2006

> Dear Python developers, > > I use a short python script in order to run an external application plus to > open a browser displaying a default page. > > My Setup: Python 2.4.3. / Windows2000 > > # ---------------------------------------------------------------------- > # Script "shortcut.py" > import os > import webbrowser > import win32api > > # open default web browser and display webbpage > page = 'C:\\Temp\\Welcome.html' > webbrowser.open(page) > > # path to application that is opened > path = "C:\\Program Files\\ExternalApplication.exe" > > # get short name > shortpath = win32api.GetShortPathName(path) > > # open external application > stdin, stdout, stderr = os.popen3(shortpath) > output = stdout.read() > errors = stderr.read() > stdin.close() > stdout.close() > stderr.close() > print output > print errors > # ---------------------------------------------------------------------- > > > In order to make this Script available on other Windows2000 machines where no > Python installation is present, I made this script executable using "py2exe" > (http://www.py2exe.org/). This creates a "shortcut.exe" file. > If I run "shortcut.exe" everything works fine but a black empty cmd window > opens and its kept open until I close the application > "ExternalApplication.exe". > How can I close that black empty window automatically? > > Thanks in advance, > Nico replace console=[... by windows=[... in your setup.py -- --- Rony Steelandt BuCodi rony dot steelandt (at) bucodi dot com Visit the python blog at http://360.yahoo.com/bucodi

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Re: Best Python Editor
by Franz Steinhaeusler May 31, 2006

May 31, 2006

On Wed, 31 May 2006 15:33:29 +0530, "Manoj Kumar P" <manojk(a)sasken.com> wrote: > >Hi, > >Can anyone tell me a good python editor/IDE? >It would be great if you can provide the download link also. > For a simple start: Scite is small, good, cross platform, free and open source and you can launch the program easy hitting F5 (run). Of course there are more powerful editors as vim, (x)emacs, jedit, ... but that depends on your intentions.

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Re: Running Python scripts under a different user
by Mikael Olofsson May 31, 2006

May 31, 2006

Laszlo Nagy wrote: > For Windows, you can use the 'runas.exe' program. But it requires a > password too. Or you can get a copy of the shareware program RunAsProfessional, which I use for my kids stupid games that necessarily has to be run by an admin. The price I paid was 10 Euro, which I still think was money well spent. IIRC you get a 30 days trial version for free. http://freedownloads.rbytes.net/cat/desktop/other3/runas-professional/ It does the same thing as RunAs, but you do not need to type the password every time you run your program. Instead the password is stored encrypted in the file you launch. I do not know what encryption is used, or how safe the encryption is. My needs are simply to make sure that my kids do not destroy anything by mistake. Sure, the stupid game may be designed to destroy, but that's another issue. /MiO

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os.popen3() - how to close cmd window automatically?
by Nico Grubert May 31, 2006

May 31, 2006

Dear Python developers, I use a short python script in order to run an external application plus to open a browser displaying a default page. My Setup: Python 2.4.3. / Windows2000 # ---------------------------------------------------------------------- # Script "shortcut.py" import os import webbrowser import win32api # open default web browser and display webbpage page = 'C:\\Temp\\Welcome.html' webbrowser.open(page) # path to application that is opened path = "C:\\Program Files\\ExternalApplication.exe" # get short name shortpath = win32api.GetShortPathName(path) # open external application stdin, stdout, stderr = os.popen3(shortpath) output = stdout.read() errors = stderr.read() stdin.close() stdout.close() stderr.close() print output print errors # ---------------------------------------------------------------------- In order to make this Script available on other Windows2000 machines where no Python installation is present, I made this script executable using "py2exe" (http://www.py2exe.org/). This creates a "shortcut.exe" file. If I run "shortcut.exe" everything works fine but a black empty cmd window opens and its kept open until I close the application "ExternalApplication.exe". How can I close that black empty window automatically? Thanks in advance, Nico

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