Announcing: python-ghostscript 0.3
Announcing: python-ghostscript 0.3 A Python-Interface to the Ghostscript C-API using ctypes :Copyright: GNU Public License v3 (GPLv3) :Author: Hartmut Goebel h.goe...@crazy-compiler.com :Homepage: http://bitbucket.org/htgoebel/python-ghostscript :Download: http://pypi.python.org/pypi/ghostscript `Ghostscript`__, is a well known interpreter for the PostScript language and for PDF. This package implements a interface to the Ghostscript C-API using `ctypes`__. Both a low-level and a pythonic, high-level interface are provided. __ http://www.ghostscript.com/ __ http://docs.python.org/library/ctypes.html This package is currently tested only under GNU/Linux. Please report whether it works in your environment, too. Thanks. Latest Changes :0.3 (2010-08-12): * Added support for win32: The DLL to load is searched in registry. * On other platforms: Be more inteligent about finding Ghostscript shared object file (fall back to ctypes.util.find_library() if `libgs.8.so` can not be loaded * Better error messages if lib/dll is not found. * Removed relative imports, so older versions of Python can be used. * Added nice project logo :0.2 (2010-08-06): * Fixed several bugs, esp. for running strings by Ghostscript. Example Here is an example for how to use the high-level interface of `python-ghostscript`. This implements a very basic ps2pdf-tool:: import sys import ghostscript args = [ ps2pdf, # actual value doesn't matter -dNOPAUSE, -dBATCH, -dSAFER, -sDEVICE=pdfwrite, -sOutputFile= + sys.argv[1], -c, .setpdfwrite, -f, sys.argv[2] ] ghostscript.Ghostscript(*args) -- Regards Hartmut Goebel | Hartmut Goebel | h.goe...@crazy-compilers.com | | www.crazy-compilers.com | compilers which you thought are impossible | -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations/
Re: urllib2 does not implement with Python 2.6
John Nagle na...@animats.com writes: AttributeError: addinfourl instance has no attribute '__exit__'. I thought that all the file-like objects supported with in 2.6. No? I guess not. Use contextlib.closing. -- http://mail.python.org/mailman/listinfo/python-list
Beyond the moratorium
Hi all. I know, maybe I'm just lazily speculating, but I'm curious about what's next, in python, when GvR will stop the moratorium and will let changes in the language. I don't know what to expect... some syntax sugar about concurrent programming? static types? an erlang-style bang (!) process message passing? -- By ZeD -- http://mail.python.org/mailman/listinfo/python-list
Why can't I set sys.ps1 to a unicode string?
More precisely, why does sys.ps1 not appear if I set it to a unicode string? This problem is hard for me to describe here because my newsreader is not properly unicode enabled, but here's the gist of it: Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type help, copyright, credits or license for more information. First, let's make sure our encodings are set properly: import sys sys.stdin.encoding 'utf-8' sys.stdout.encoding 'utf-8' Looks good. Now, let's make two unicode strings, identical except for one character: s1 = u'%%% %%% ' s2 = u'%%% ' + u'\u262f' + '%%% ' print s1 %%% %%% print s2 %%% /%%% If this were a properly unicode-enabled newsreader you would see a yin-yang symbol in the middle of s2. Now the weird part: sys.ps1 = s1 %%% %%% sys.ps1 = s2 # This is as expected print s1 # But this isn't. There's no prompt! %%% %%%# Everything still works print s2 %%% /%%% sys.ps1 = s1 # If we reset sys.ps1 we get our prompt back %%% %%% sys.ps1 = ' ' sys.ps1 = u' ' So... why does having a non-ascii character in sys.ps1 make the prompt vanish? (If you're wondering why I care, I want to connect to an interactive python interpreter from another program, and I want a non-ascii delimiter to unambiguously mark the end of the interpreter's output on every interaction.) Thanks, rg -- http://mail.python.org/mailman/listinfo/python-list
Re: python ide for ubuntu
Eclipse with pydev (great debugging) does the trick nicely, free of charge and throws in some other goodies (JScript/HTML/XML editing) too. I use the EE for Java developer version http://www.eclipse.org/downloads/packages/eclipse-ide-java-ee-developers/heliosr Install pydev from Menu Help/Software Updates After ten years of Python coding and suffering thru most of the commercial products like VisualPython, Komodo, Wings, asf I heartily recommend Eclipse nowadays. If you want to stay as pythonesque as possible you could go with SPE which uses wxPython and integrates with Blender, although this project seems to be stalled. Werner On 12.08.2010 04:15, Bhanu Kumar wrote: Hi All, Is there any good free python IDE available in Ubuntu? thanks, -Bhanu attachment: werner.vcf-- http://mail.python.org/mailman/listinfo/python-list
Re: Why is python not written in C++ ?
sturlamolden wrote: On 11 Aug, 08:40, Ulrich Eckhardt eckha...@satorlaser.com wrote: Header (definition) and source (implementation) is not the same. I'm aware of this and that's not the thing I was talking about. Uli -- Sator Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Beyond the moratorium
Vito 'ZeD' De Tullio, 12.08.2010 08:49: I know, maybe I'm just lazily speculating, but I'm curious about what's next, in python, when GvR will stop the moratorium and will let changes in the language. I don't know what to expect... some syntax sugar about concurrent programming? static types? an erlang-style bang (!) process message passing? One of the reasons the moratorium was established was to reduce the time spent in overly speculative discussions about various features that will most likely not end up in the language anyway. Also note that your examples above span both the language and the stdlib, which are put under different constraints by the moratorium. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Beyond the moratorium
Vito 'ZeD' De Tullio zak.mc.kra...@libero.it writes: I know, maybe I'm just lazily speculating, but I'm curious about what's next, in python, when GvR will stop the moratorium and will let changes in the language. Subscribe to the ‘python-ideas’ forum for the latest pie-in-the-sky discussions about how to change Python, including the occasional contribution from GvR on ideas that take his interest. -- \ “In the long run, the utility of all non-Free software | `\ approaches zero. All non-Free software is a dead end.” —Mark | _o__)Pilgrim, 2006 | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Why can't I set sys.ps1 to a unicode string?
So... why does having a non-ascii character in sys.ps1 make the prompt vanish? I can't pinpoint it to a specific line of code. Most likely, it tries to encode the prompt as ASCII before writing it to stdout. That fails, and it silently ignores the error. FWIW, this is fixed in Python 3. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
Hi Steven, On 08/12/2010 01:37 AM, Steven D'Aprano wrote: On Wed, 11 Aug 2010 13:14:35 -0700, Baba wrote: level: beginner exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. Is this a trick question? I'd like to see somebody try to buy exactly 10**100**100 (1 googleplex) McNuggets. And that's not even close to the largest number that you can't buy. You CAN buy that many Nuggets. You just need the money and of course you have to wait a little until they are ready. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to save a whole web page with something block
In message mailman.1921.1281452652.1673.python-l...@python.org, Daniel Fetchinson wrote: A web server may present different output depending on the client used. It may also require execution of some JavaScript to insert HTML content. So you might want to make urllib appear as a browser by sending the appropriate headers. If the above is the case, then this won’t be enough. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
Steven D'Aprano wrote: On Wed, 11 Aug 2010 13:14:35 -0700, Baba wrote: level: beginner exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. Is this a trick question? I'd like to see somebody try to buy exactly 10**100**100 (1 googleplex) McNuggets. And that's not even close to the largest number that you can't buy. If you'd looked at the link then you would've seen that it's mathematically possible. But then I expect you have a life! :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: python ide for ubuntu
On Wed, Aug 11, 2010 at 11:53 PM, Werner Thie wer...@thieprojects.ch wrote: Eclipse with pydev (great debugging) does the trick nicely, free of charge and throws in some other goodies (JScript/HTML/XML editing) too. I use the EE for Java developer version http://www.eclipse.org/downloads/packages/eclipse-ide-java-ee-developers/heliosr Install pydev from Menu Help/Software Updates After ten years of Python coding and suffering thru most of the commercial products like VisualPython, Komodo, Wings, asf I heartily recommend Eclipse nowadays. If you want to stay as pythonesque as possible you could go with SPE which uses wxPython and integrates with Blender, although this project seems to be stalled. Werner Or you could use a text editor and a terminal and spare yourself the agony of dealing with 600MB of Java of questionable quality ;). And don't even get me started about all the unsigned OSGi bundles that float around in there. Geremy Condra -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
On 08/11/2010 10:14 PM, Baba wrote: level: beginner exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. exercise source: http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-00-introduction-to-computer-science-and-programming-fall-2008/assignments/pset2.pdf please help me write this code i believe it's something along the lines of this: c=0 sol=[] for n in range (0,10): for a in range (0,10): for b in range (0,10): for c in range (0,10): sol=6*a+9*b+20*c if sol!=n: c+=1 if c==6: print sol If you're interested in more, than just finishing the exercise, then you should post your solution even if you have it already and read about all the tips how to make it faster or shorter or more readable -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Tkinter Simple Qn
In article
ecd3ebca-8192-445a-a60c-c688b18f4...@i4g2000prf.googlegroups.com,
ChrisChia chrischi...@gmail.com wrote:
Hi i have the following problem with Python Tkinter.
I switch to switch the image background (which i used Tkinter.Label
with image arg to display on the GUI).
How can I do that? the callback function which i have created doesn't
seem to work...
It is usually way better to post the actual error than just saying
doesn't seem to work Here your problem is quite clear, but in most
circumstances, it would be quite difficult to figure out what's
happening.
some advice?
below is my code:
import Tkinter as tk
from PIL import Image, ImageTk
root = tk.Tk()
# having problem with switching the image
def callback(event):
global root
root.panel1.pack_forget()
root.panel1.image = image2
The variable image2 is not known in this context, so no wonder the
callback doesn't work. Let me guess: it says something like NameError:
name 'image2' is not defined?
root.panel1.pack()
def app():
root.title('FIT 2022 Assignment 1')
# pick an image file you have .bmp .jpg .gif. .png
# load the file and covert it to a Tkinter image object
imageFile = c:\\test1.jpg
image1 = ImageTk.PhotoImage(Image.open(imageFile))
imageFile2 = c:\\test2.jpg
image2 = ImageTk.PhotoImage(Image.open(imageFile2))
Here, you create image2 as a local variable in function app. So the
variable name will not be known outside of app. If you want it to be
global, you have to add a line:
global image2
at the beginning of your app function. Then it should work correctly.
By the way, I usually find it better to organize a GUI into classes
rather than using functions. This way, you could store the images in
object attributes and define your callback as a method, and not as a
function.
# get the image size
w = image1.width()
h = image1.height()
# position coordinates of root 'upper left corner'
x = 0
y = 0
# make the root window the size of the image
root.geometry(%dx%d+%d+%d % (w, h, x, y))
# root has no image argument, so use a label as a panel
panel1 = tk.Label(root, image=image1)
panel1.pack(side='top', fill='both', expand='yes')
panel1.image = image1
panel1.bind(Button-1, callback)
panel1.pack()
root.mainloop()
app()
HTH
- Eric -
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Re: most popular gui framework for python
On Aug 11, 8:31 pm, Back9 backgoo...@gmail.com wrote: Hi, Does anyone know of what is the most popular gui framework for python application? TIA I used to prefer using GTK mainly because it is available on most platforms. I have realised the majority of the enterprises prefer to use browsers even for local applications. So a combination of django/ html/css/jquery/ajax now gives me the best gui I could get. This approach also forces me to separate logic from presentation, and the gui will be truly platform independent which could run on any device with a browser. Meitham -- http://mail.python.org/mailman/listinfo/python-list
Does anyone use Quixote for web developing?
Hi all,I am learning Quixote a few days ago,,,and i have no idea about whether there is any Google Group talking about Quixote,so i post this post to check that is Quixote been talking in this group before or can i ask question about Quixote here! -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Baba wrote: level: beginner exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. exercise source: http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-00-introduction-to-computer-science-and-programming-fall-2008/assignments/pset2.pdf please help me write this code i believe it's something along the lines of this: c=0 sol=[] for n in range (0,10): for a in range (0,10): for b in range (0,10): for c in range (0,10): sol=6*a+9*b+20*c if sol!=n: c+=1 if c==6: print sol for mcNugget in range(0,10): sendTo(trashbin) You're welcome :p JM -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Baba raoul...@gmail.com writes: exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. Is that a homework problem? Hint: first convince yourself that a largest number actually exists. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does anyone use Quixote for web developing?
ph4nut a écrit : Hi all,I am learning Quixote a few days ago,,,and i have no idea about whether there is any Google Group talking about Quixote,so i post this post to check that is Quixote been talking in this group before or can i ask question about Quixote here! From the project's home page: There is a mailing list for discussing Quixote and you should look there for information about obtaining the current release: * quixote-users -- http://mail.python.org/mailman/listinfo/python-list
Re: python ide for ubuntu
geremy condra a écrit : (about eclipse+pydev) Or you could use a text editor and a terminal and spare yourself the agony of dealing with 600MB of Java of questionable quality ;). +1 QOTW -- http://mail.python.org/mailman/listinfo/python-list
Re: cx_Oracle 5.0.4 + Python 3.1.2 + Oracle Instant Client 10.2.04; DLL Load failed on import (Win/NT)
Hello, On Wed, Aug 11, 2010 at 02:29:24PM -0700, tormod wrote: I've tried countless times to build install cx_Oracle on Python 3.1.2, and failed every time, so I'd like to ask someone for help. ... I've opened the cx_Oracle.pyd with Dependency Walker (http:// www.dependencywalker.com/) and DW reports it can't find: OCI.DLL, PYTHON31.DLL, MSVCR90.DLL (why?) Does Windows have anything like LD_LIBRARY_PATH/SHLIB_PATH? Appreciate any help, even wildshots and 2 cents are welcome - I'll try everything. please try starting python -d (--debug IIRC) and then loading cx_Oracle manually ( import cx_Oracle). Usually it succeeds (sic!) but outputs a lot of symbol errors. // Problem with Oracle libs -- With best regards, xrgtn (+380501102966/+380636177128/xr...@jabber.kiev.ua) -- http://mail.python.org/mailman/listinfo/python-list
Re: python ide for ubuntu
Hi Bhanu, On Aug 12, 2010, at 4:15 AM, Bhanu Kumar wrote: Hi All, Is there any good free python IDE available in Ubuntu? See a similar discussion at django-users mailing list: http://groups.google.com/group/django-users/browse_thread/thread/562189578285211 Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Aug 12, 2010, at 11:33 AM, Paul Rubin wrote: Baba raoul...@gmail.com writes: exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. Is that a homework problem? Hint: first convince yourself that a largest number actually exists. Good point. There is actually an upper bound. Let's take 6 packs of 20, that's 120 nuggets. Now 121 nuggets can be reached by substituting 1 pack of 20 with 2 packs of 6 and 1 pack of 9. 122 = 4*20 + 2*(2*6+9) 123 = 3*20 + 3*(2*6+9) ... 126 = 6*20 + 6 127 = 121 + 6 = 5*20 + (2*6 + 9) + 6 ... etcetera. Now you have to find the largest number below 120, which you can easily do with brute force (untested): can_be_bought = [False for i in range(120)] for twenties in range(6): for nines in range(14): for sixes in range(20): can_be_bought[twenties*20+nines*9+sixes*6] = True for i in reverse(range(120)): if not can_be_bought[i]: return i Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Programming Puzzles? What's your favorite puzzle?
Hey All! Hope your thursday is treating you well. I'm looking for suggestions on books of programming/engineering puzzles that range from beginners to advanced and even expert level problems. I know they exist; we had them back in college for practicing before the ACM programming competitions. However I can't seem to really find any books out there that look like they're what I'm seeking. Basically I haven't programmed a lot since I was in college, and that was about 9 years ago. I'm expected to do a bit more programming at my current job and I figure the best way to get back into things is to have some practical things to solve, and maybe have a bit of fun in the process. Anyone have any suggestions? Also, if you have any favorite puzzles/simple learning programs to suggest, please, share with the class :) -Matty -- http://mail.python.org/mailman/listinfo/python-list
Copying a file with a question mark in it's name in Windows
A python script I use to backup files on a Windows 2003 server occasionally fails to retrieve the size of a file with a question mark in the name. The exception I get is OSError #123 The filename, directory name, or volume label syntax is incorrect. I realize that technically a question mark in the name of a file on Windows is illegal, but nevertheless these files exist on the file system. It seems that they are created by Office 2007 Word, for the most part. The line that fails is: os.path.getsize(source) Where source is the full path to the file with the question mark in it's name. Any idea how to retrieve the file's size? Also, I imagine that after I overcome this hurdle, I'll need help finding a way to copy the file (assuming copy2() doesn't work). I've tried escaping the question mark (\\?). Same result. Although I could use the Windows dir command, parsing the results to find the size of the file then use the Windows copy command, I'd rather stay away from this type of solution. Any help is appreciated! -- http://mail.python.org/mailman/listinfo/python-list
Long rant about Python in Education
This is in response to one of the pyWiki pages: PythonAsAFirstLanguage. If there's a better place I could have posted this, please tell me about it. I will be posting this elsewhere over the next few ideas, because I feel it's my duty to spread this idea. It's not grandiose, just Quixotic. Someone wrote, We could really use some success stories of Python in education. Right... Python was developed to be easily learnt by children. So that's not a declarative sentence. It's an implied question. Here's my answer. It took a while to write, but it's quite simple. Problem: Python won't be easily learnt by my stepchild, I know for a fact. She loves her laptop, but she calls me a nerd whenever Linux gets brought up at the dinner table. I'm not bitter about this. But I want you guys, especially the ones who are planning on having kids, as well as the ones who already have them, to understand what steps you can take to teach your kids Python. I've basically outlined an 'algorithm' for it here. If you don't have time to read a long, eccentric, rambling post, just 'read the lead' Solution to problem: 1) Only let them see you using the terminal. Don't even use Windows in the house. 2) Their first laptop should be installed with a nice, well-supported Linux distro. 3) Brush up on your Linux skills yourself. The bottom line: teach them to do beautiful things with the terminal. I believe Linux should be mastered by everyone who uses it. And I believe Linux (not Python) is the way to teach children to program. Especially intuitive ones. (In the Myers-Briggs scale.) Why is this important? Because the part of the world that most hates America right now is full of intuitives. And if we want not to be blown off the face of the earth in a few decades, we have to empower them in a very new way: we have to teach them to enjoy programming, enjoy computers, and develop their minds in a way that doesn't involve becoming 'Imams' who are essentially the learned mafia bosses of terrorism. I have mastered Classical Arabic. I once met a Pakistani and told him I had done so. We were in the middle of a theological debate. In the middle of his Islamic theology was, laughably enough, some Christian theology that I have no idea how it got there. Orthodox Islam has no concept of original sin, but he believed in it. That was a real surprise for me. Anyway, despite the fact that he'd only read translations of the Qur'an, whereas I'd read the original, he was not impressed. He said that Pakistan had many 'schools' for studying Arabic, and that there was an incredible number of 'students' there. These people aren't dumb, guys. They're just learning the wrong stuff. We can't change the schools, but we don't need to. Don't forget that Arabs and Central Asians both had education systems based on Islam before western education came with the French and British. The attempt to re-establish the primacy of that system of education is what Islamic terrorism is all about. It was based on memorizing/hearing the Qur'an, yes, then learning the meanings of the words by reading it. Actually, for an intuitive person, this is an excellent way to learn any language (find a text, find a recording, memorize the recording, intuit the meanings) and I have used it to learn Spanish, Chinese, and Arabic. How does this apply to Linux/Python? Having access to the /usr/bin directory means having access to a whole load of algorithms without even having to write them yourself! Hasn't anyone but me thought of how great that would be for kids? So, when you guys ban windows in the home and start breastfeeding your kids terminals (I was using a DOS terminal correctly at age 9, shouldn't be hard to teach them whippersnappers to use a -nix shell), then you can bring in Python. But first, start writing Python to put in their /usr/bin directories, so that they get comfortable with the idea that Python can be both scripted and compiled, and that programs are simply algorithms that get called using arguments. Then teach them to write Python stuff they can put into /usr/bin Important: ban windows entirely in the home. I cannot stress this enough. My stepdaughter is as good with computers as I was at her age, and I've seen her play around with the settings on her laptop when she's bored. Obviously, she wants to explore the machine sometimes, but windows has trained her mind not to look for geeky solutions. Windows has trained her to think of a computer as a magic machine, and not as an algorithm machine. Will the real Bill Gates please stand up. When I was her 10, my stepfather banned me from playing DOOM unless I could get it to work using the DOS command line. I did not manage to replace the .dll file he had deleted, but I did learn lots. Will the real Bill Gates please stand up, please stand up, please stand up... So, in conclusion: DO people of the free-thinking world want a Mozart Python genius to show off to the schools in Europe, Japan,
Re: Copying a file with a question mark in it's name in Windows
On 12/08/2010 12:49, drodrig wrote: A python script I use to backup files on a Windows 2003 server occasionally fails to retrieve the size of a file with a question mark in the name. The exception I get is OSError #123 The filename, directory name, or volume label syntax is incorrect. I realize that technically a question mark in the name of a file on Windows is illegal, but nevertheless these files exist on the file system. It seems that they are created by Office 2007 Word, for the most part. Could you show us the script you're using? I'm not aware of any way to get a question mark into a file name; even using the file namespace prefix \\?\ doesn't allow it as far as I can tell. Where are you seeing the question mark? Is it possible it's a placeholder for an unprintable character rather than an actual question mark? TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Beyond the moratorium
On Aug 12, 1:22 am, Ben Finney ben+pyt...@benfinney.id.au wrote: Vito 'ZeD' De Tullio zak.mc.kra...@libero.it writes: I know, maybe I'm just lazily speculating, but I'm curious about what's next, in python, when GvR will stop the moratorium and will let changes in the language. Subscribe to the ‘python-ideas’ forum for the latest pie-in-the-sky discussions about how to change Python, including the occasional contribution from GvR on ideas that take his interest. -- \ “In the long run, the utility of all non-Free software | `\ approaches zero. All non-Free software is a dead end.” —Mark | _o__) Pilgrim, 2006 | Ben Finney You might also want to look at PEP 3152, which was just posted. John Roth -- http://mail.python.org/mailman/listinfo/python-list
Secure LDAP Configuration
I want to create an LDAP database for my company with following
settings.
Only the ldap user belongs to my company can search and view ldap
entries
I want to protect ldap user belongs to my company
One ldap user can't search and view others details
Only allow ldap users to authenticate with there username and
password
I need an LDAP administrator for my company.Only he can add and
delete users from LDAP.
For these how configure /etc/openldap/slapd.conf
I need to add group and role infornations to ldap directory.Can i use
existing attributes like 'ou' for these or need to add new attribute.
Here is the LDAP entry i configured.
dn: uid=user6,dc=localhost,dc=localdomain
objectclass: top
objectclass: person
objectclass: inetorgperson
ou: [('userGroup111','userr'),('adminGroup','admin'),
('Server111','operator')]
cn: user6
sn: My company
uid: user6
userPassword: 123456
ou: [('userGroup111','userr'),('adminGroup','admin'),
('Server111','operator')] -newly added group and role pair.Is it
correct way
Have any other way to do it.
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Renaming OS files by file type in python
Hi all, I am creating a program that renames all files of the similar file type. But i am stuck at this part. I tried running this code and I got this error:new_name = os.rename(path, newpath) WindowsError: [Error 183] Cannot create a file when that file already exists. Hope you guys could help. import os directory = raw_input(Please input file directory. \n\n) s = raw_input(Please input a name to replace. \n\n) ext = raw_input(input file ext) for filename in listdir(directory): if ext in filename: path = join(directory, filename) fnpart = os.path.splitext(filename)[0] replace_name = filename.replace(fnpart, s) newpath = os.path.join(directory, replace_name) new_name = os.rename(path, newpath) print new_name -- http://mail.python.org/mailman/listinfo/python-list
Re: Copying a file with a question mark in it's name in Windows
On 12 авг, 18:49, drodrig drod...@magicbrain.com wrote: A python script I use to backup files on a Windows 2003 server occasionally fails to retrieve the size of a file with a question mark in the name. The exception I get is OSError #123 The filename, directory name, or volume label syntax is incorrect. I realize that technically a question mark in the name of a file on Windows is illegal, but nevertheless these files exist on the file system. It seems that they are created by Office 2007 Word, for the most part. If ? is a placeholder for an unprintable character you can try view real file name in IDLE: import glob print glob.glob(u'e:/full/path/to/file?') In path to file you must instead question use wild ?. Will be printed all like files. - Under Windows I too have similar problem: windows sometimes (from any programs - e.g. Firefox) save files with wrong names, but later do not manipulate with it. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Roald de Vries wrote: div class=moz-text-flowed style=font-family: -moz-fixedOn Aug 12, 2010, at 11:33 AM, Paul Rubin wrote: Baba raoul...@gmail.com writes: exercise: given that packs of McNuggets can only be bought in 6, 9 or 20 packs, write an exhaustive search to find the largest number of McNuggets that cannot be bought in exact quantity. Is that a homework problem? Hint: first convince yourself that a largest number actually exists. Good point. There is actually an upper bound. Let's take 6 packs of 20, that's 120 nuggets. Now 121 nuggets can be reached by substituting 1 pack of 20 with 2 packs of 6 and 1 pack of 9. 122 = 4*20 + 2*(2*6+9) 123 = 3*20 + 3*(2*6+9) ... 126 = 6*20 + 6 127 = 121 + 6 = 5*20 + (2*6 + 9) + 6 ... etcetera. Now you have to find the largest number below 120, which you can easily do with brute force (untested): can_be_bought = [False for i in range(120)] for twenties in range(6): for nines in range(14): for sixes in range(20): can_be_bought[twenties*20+nines*9+sixes*6] = True for i in reverse(range(120)): if not can_be_bought[i]: return i Cheers, Roald for i in reverse(range(120)): if not can_be_bought[i]: return i can probably be replaced by (untested): return len(can_be_bought) - reverse(can_be_bought).index(False) - 1 DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Programming Puzzles? What's your favorite puzzle?
Matty Sarro wrote: Hey All! Hope your thursday is treating you well. I'm looking for suggestions on books of programming/engineering puzzles that range from beginners to advanced and even expert level problems. I know they exist; we had them back in college for practicing before the ACM programming competitions. However I can't seem to really find any books out there that look like they're what I'm seeking. Basically I haven't programmed a lot since I was in college, and that was about 9 years ago. I'm expected to do a bit more programming at my current job and I figure the best way to get back into things is to have some practical things to solve, and maybe have a bit of fun in the process. Anyone have any suggestions? Also, if you have any favorite puzzles/simple learning programs to suggest, please, share with the class :) -Matty For puzzles: http://projecteuler.net http://www.pythonchallenge.com And you might get some ideas from: http://wiki.python.org/moin/CodingProjectIdeas DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Long rant about Python in Education
On Thu, 12 Aug 2010 05:05:55 -0700 (PDT) เข้านอน iktomus.heyo...@gmail.com wrote: have to teach them to enjoy programming, enjoy computers, and develop their minds in a way that doesn't involve becoming 'Imams' who are essentially the learned mafia bosses of terrorism. This is the point that I stopped reading your message and added you to my blacklist. Goodbye. -- D'Arcy J.M. Cain da...@druid.net | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: How does Python get the value for sys.stdin.encoding?
Benjamin Kaplan benjamin.kap...@case.edu writes: Sys.stdin and stdout are files, just like any other. There's nothing special about them at compile time. When the interpreter starts, it checks to see if they are ttys. If they are, then it tries to figure out the terminal's encoding based on the environment. Just a related question, is looking at sys.stdin.encoding the proper way of doing things? I've been working on a script to display some email headers, some of which are encoded in MIME to various charsets. Until now I have used whatever locale.getdefaultlocale() returns as the target encoding, since it seemed to work. Although on one computer the call returns ISO-8859-15 even though I don't quite understand why. -- http://mail.python.org/mailman/listinfo/python-list
__class__ of what
Hello, I have, class C: n=0 def __init__(s): __class__.n+=1 I do C() This is fine. But of what thing I am taking the __class__ of? I can also do @staticmethod def p(): print(__class__.n) C.p() 1 Thanks, Eric J. -- http://mail.python.org/mailman/listinfo/python-list
Re: Programming Puzzles? What's your favorite puzzle?
On 2010-08-12, Dave Angel da...@ieee.org wrote: For puzzles: http://projecteuler.net ...if you like math problems. http://www.pythonchallenge.com ...if you like fooling around with PIL, graphics and bytes. -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
Using elementtree to Create HTML Form / Set selected
I'm using elementtree to create a form. I would like to set the selected attribute. Setting using the usual option.set( selected = ) gives me option selected= value=operationsOperations/option how does one make option selected value=operationsOperations/option which is what I need. -- http://mail.python.org/mailman/listinfo/python-list
Re: Does anyone use Quixote for web developing?
On Aug 12, 5:40 pm, Bruno Desthuilliers bruno. 42.desthuilli...@websiteburo.invalid wrote: ph4nut a écrit : Hi all,I am learning Quixote a few days ago,,,and i have no idea about whether there is any Google Group talking about Quixote,so i post this post to check that is Quixote been talking in this group before or can i ask question about Quixote here! From the project's home page: There is a mailing list for discussing Quixote and you should look there for information about obtaining the current release: * quixote-users Thanks,I will have a check! -- http://mail.python.org/mailman/listinfo/python-list
Re: Does anyone use Quixote for web developing?
On Aug 12, 5:40 pm, Bruno Desthuilliers bruno. 42.desthuilli...@websiteburo.invalid wrote: ph4nut a écrit : Hi all,I am learning Quixote a few days ago,,,and i have no idea about whether there is any Google Group talking about Quixote,so i post this post to check that is Quixote been talking in this group before or can i ask question about Quixote here! From the project's home page: There is a mailing list for discussing Quixote and you should look there for information about obtaining the current release: * quixote-users Thanks,I will have a check! -- http://mail.python.org/mailman/listinfo/python-list
Re: __class__ of what
Eric J. Van der Velden wrote: Hello, I have, class C: n=0 def __init__(s): __class__.n+=1 Should be class C: n = 0 def __init__(self): self.__class__.n+=1 C.n+=1 # equivalent to this line (I prefer this one, more readable, less refactor-friendly) @classmethod def p(cls): print(cls.n) JM -- http://mail.python.org/mailman/listinfo/python-list
Re: __class__ of what
In article 72151646-65cb-47bb-bd55-e7eb67577...@z10g2000yqb.googlegroups.com, Eric J. Van der Velden ericjvandervel...@gmail.com wrote: Hello, I have, class C: n=0 def __init__(s): __class__.n+=1 I do C() This is fine. No it's not, at least in Python 2.x: C() Traceback (most recent call last): File stdin, line 1, in module File stdin, line 4, in __init__ NameError: global name '__class__' is not defined But of what thing I am taking the __class__ of? Nothing, precisely. You should write s.__class__ (and replace s by self while you're at it). I can also do @staticmethod def p(): print(__class__.n) C.p() 1 No you can't, again in Python 2.x: C.p() Traceback (most recent call last): File stdin, line 1, in module File stdin, line 4, in p NameError: global name '__class__' is not defined Unless I'm missing something or something fundamental changed in Python 3, your examples do not work Thanks, Eric J. -- http://mail.python.org/mailman/listinfo/python-list
Re: __class__ of what
Eric J. Van der Velden wrote: I have, class C: n=0 def __init__(s): __class__.n+=1 I do C() This is fine. But of what thing I am taking the __class__ of? I can also do @staticmethod def p(): print(__class__.n) C.p() 1 I had no idea that this existed. __class__ was probably added to make super() calls without an explicit class argument possible in Python 3. It is made available as a closure: class A: ... def f(self): __class__ ... def g(self): pass ... A.f.__closure__[0].cell_contents class '__main__.A' A.g.__closure__ is None True Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Using elementtree to Create HTML Form / Set selected
Doug wrote: I'm using elementtree to create a form. I would like to set the selected attribute. Setting using the usual option.set( selected = ) Maybe that should be option.set(selected=selected). I think option selected=selected and option selected are equivalent. http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4.2 gives me option selected= value=operationsOperations/option how does one make option selected value=operationsOperations/option which is what I need. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using elementtree to Create HTML Form / Set selected
On Aug 12, 10:47 am, Peter Otten __pete...@web.de wrote: Doug wrote: I'm using elementtree to create a form. I would like to set the selected attribute. Setting using the usual option.set( selected = ) Maybe that should be option.set(selected=selected). I think option selected=selected and option selected are equivalent. http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4.2 gives me option selected= value=operationsOperations/option how does one make option selected value=operationsOperations/option which is what I need. Makes sense to me. Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: __class__ of what
Hello Jean-Michel,
On 2010-08-12 16:06, Jean-Michel Pichavant wrote:
Eric J. Van der Velden wrote:
Should be
class C:
n = 0
def __init__(self):
self.__class__.n+=1
C.n+=1 # equivalent to this line (I prefer this one, more
readable, less refactor-friendly)
I think both lines have slightly different semantics if you
consider instantiating an object of a derived class. (The
following formatting is from IPython, thus the differences
to the usual interpreter output.)
Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56)
class C(object):
... n = 0
... def __init__(self):
... self.__class__.n += 1
...
class D(C):
... pass
...
d = D()
D.n
1
C.n
0
Here, the augmented assignment looks up self.__class__.n
which it doesn't find and so gets it from class C. The
actual assignment assigns to D.n, however.
On the other hand:
class C(object):
... n = 0
... def __init__(self):
... C.n += 1
...
class D(C):
... pass
...
d = D()
D.n
1
C.n
1
Here, only C is changed. D doesn't get an own attribute n,
and after the instantiation of d, D.n looks up and gets n
from the base class C.
Curiously,
dir(D)
['__class__',
'__delattr__',
'__dict__',
'__doc__',
'__format__',
'__getattribute__',
'__hash__',
'__init__',
'__module__',
'__new__',
'__reduce__',
'__reduce_ex__',
'__repr__',
'__setattr__',
'__sizeof__',
'__str__',
'__subclasshook__',
'__weakref__',
'n']
seems to contain n (is it supposed to be listed here?), but
dict(D.__dict__)
{'__doc__': None, '__module__': '__main__'}
indicates that D doesn't contain n. But C does:
dict(C.__dict__)
{'__dict__': attribute '__dict__' of 'C' objects,
'__doc__': None,
'__init__': function __init__ at 0xb70c2454,
'__module__': '__main__',
'__weakref__': attribute '__weakref__' of 'C' objects,
'n': 1}
I hope everything I wrote above is valid. If not, please
correct me. :-)
Anyway, depending on what you want, either of the two
variants might be ok. In any case I'd include a meaningful
comment on why you actually wrote what you wrote. :-)
Stefan
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Inserting/Deleting newline(s) in very large text files
Hi, I am dealing with very large text files (a few million lines) and would like to check and modify them according to a well defined format. The format requires ONLY ONE NEWLINE (followed by some sort of text) on top of the file and NO NEWLINE in the very end. The input files can be very diverse, such as one file may have 2 newlines on top and none in the end or other may not have a newline on top and 5 in the end. The aim is to check these files introduce JUST ONE NEWLINE in the TOP and NO NEWLINE in the BOTTOM. Any pointers will be appreciated. Thanks, DS. -- http://mail.python.org/mailman/listinfo/python-list
Announcing: python-ghostscript 0.3
Announcing: python-ghostscript 0.3 A Python-Interface to the Ghostscript C-API using ctypes :Copyright: GNU Public License v3 (GPLv3) :Author: Hartmut Goebel h.goe...@crazy-compiler.com :Homepage: http://bitbucket.org/htgoebel/python-ghostscript :Download: http://pypi.python.org/pypi/ghostscript `Ghostscript`__, is a well known interpreter for the PostScript language and for PDF. This package implements a interface to the Ghostscript C-API using `ctypes`__. Both a low-level and a pythonic, high-level interface are provided. __ http://www.ghostscript.com/ __ http://docs.python.org/library/ctypes.html This package is currently tested only under GNU/Linux. Please report whether it works in your environment, too. Thanks. Latest Changes :0.3 (2010-08-12): * Added support for win32: The DLL to load is searched in registry. * On other platforms: Be more inteligent about finding Ghostscript shared object file (fall back to ctypes.util.find_library() if `libgs.8.so` can not be loaded * Better error messages if lib/dll is not found. * Removed relative imports, so older versions of Python can be used. * Added nice project logo :0.2 (2010-08-06): * Fixed several bugs, esp. for running strings by Ghostscript. Example Here is an example for how to use the high-level interface of `python-ghostscript`. This implements a very basic ps2pdf-tool:: import sys import ghostscript args = [ ps2pdf, # actual value doesn't matter -dNOPAUSE, -dBATCH, -dSAFER, -sDEVICE=pdfwrite, -sOutputFile= + sys.argv[1], -c, .setpdfwrite, -f, sys.argv[2] ] ghostscript.Ghostscript(*args) -- Regards Hartmut Goebel | Hartmut Goebel | h.goe...@crazy-compilers.com | | www.crazy-compilers.com | compilers which you thought are impossible | -- http://mail.python.org/mailman/listinfo/python-list
Re: Programming Puzzles? What's your favorite puzzle?
On Thu, Aug 12, 2010 at 5:41 AM, Matty Sarro msa...@gmail.com wrote: Hey All! Hope your thursday is treating you well. I'm looking for suggestions on books of programming/engineering puzzles that range from beginners to advanced and even expert level problems. I know they exist; we had them back in college for practicing before the ACM programming competitions. However I can't seem to really find any books out there that look like they're what I'm seeking. Basically I haven't programmed a lot since I was in college, and that was about 9 years ago. I'm expected to do a bit more programming at my current job and I figure the best way to get back into things is to have some practical things to solve, and maybe have a bit of fun in the process. Anyone have any suggestions? http://www.spoj.pl/ http://www.codechef.com/ Many of the problems at those sites are difficult in Python due to the time constraints, but they're well worth checking out. Cheers, Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Announcing: python-ghostscript 0.3
Hartmut Goebel schreef op de 12e dag van de oogstmaand van het jaar 2010:
Here is an example for how to use the high-level interface of
`python-ghostscript`. This implements a very basic ps2pdf-tool::
import sys
import ghostscript
args = [
ps2pdf, # actual value doesn't matter
-dNOPAUSE, -dBATCH, -dSAFER,
-sDEVICE=pdfwrite,
-sOutputFile= + sys.argv[1],
-c, .setpdfwrite,
-f, sys.argv[2]
]
ghostscript.Ghostscript(*args)
How is this different from os.system(' '.join(args)) ?
--
Peter Kleiweg L:NL,af,da,de,en,ia,nds,no,sv,(fr,it) S:NL,de,en,(da,ia)
info: http://www.let.rug.nl/kleiweg/ls.html
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unicode string alteration
HELP!!! I need help with a unicode issue that has me stumped. I must be doing something wrong because I don't believe this condition would have slipped thru testing. Wherever the string u'\udbff\udc00' occurs u'\U0010fc00' or unichr(1113088) is substituted and the file loses 1 character resulting in all trailing characters being shifted out of position. No other corrupt strings have been detected. The condition was noticed while testing in Python 2.6.5 on Ubuntu 10.04 where the maximum ord # is 1114111 (wide Python build). Using Python 2.5.4 on Windows-ME where the maximum ord # is 65535 (narrow Python build) the string u'\U0010fc00' also occurs and it seems that the substitution takes place but no characters are lost and file sizes are ok. Note that ord(u'\U0010fc00') causes the following error: TypeError: ord() expected a character, but string of length 2 found The condition is otherwise invisible in 2.5.4 and is handled internally without any apparent effect on processing with characters u'\udbff' and u'\udc00' each being separately accessible. The first part of the attachment repeats this email but also has examples and illustrates other related oddities. Any help would be greatly appreciated. Bruce Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) [GCC 4.4.3] on linux2 Type copyright, credits or license() for more information. Personal firewall software may warn about the connection IDLE makes to its subprocess using this computer's internal loopback interface. This connection is not visible on any external interface and no data is sent to or received from the Internet. IDLE 2.6.5 = RESTART = HELP!!! I need help with a unicode issue that has me stumped. I must be doing something wrong because I don't believe this condition would have slipped thru testing. Script output in the next section w/data = map(unichr,xrange(56317,56323)) Reveals a condition where a unicode string is corrupted when created. Wherever the string u'\udbff\udc00' occurs u'\U0010fc00'...unichr(1113088) is substituted and the file loses 1 character resulting in all trailing characters being shifted out of position. No other corrupt strings have been detected. The condition was noticed while testing in Python 2.6.5 on Ubuntu 10.04 where the maximum ord # is 1114111 (wide Python build). Using Python 2.5.4 on Windows-ME where the maximum ord # is 65535 (narrow Python build) the string u'\U0010fc00' also occurs and it seems that the substitution takes place but no characters are lost and file sizes are ok. Note that ord(u'\U0010fc00') causes the following error: TypeError: ord() expected a character, but string of length 2 found The condition is otherwise invisible in 2.5.4 and is handled internally without any apparent effect on processing with characters u'\udbff' and u'\udc00' each being separately accessible. In Python 2.5.4/win32(ME) the system substitutes U0010fc00 but is othersize ok as the system handles these events internally without any other known effect. NOTE: In Python 2.6.5/linux2(ubuntu 10.04) the system may not substitute immediately but returns different lengths depending on the method of length request. len(u'\udbff\udc00') returns a shorter len than: u2 = u'\udbff\udc00'; len(u2) In those cases the variable reference method (len(u2)) is more accurate eventhough the variable value and the string value are identical. I have evidence of this string resulting in a file losing 1 character for each time the string occurs on write to file. As a test I reversed the string sequence and used the same commands to write to file, everything was fine. I think the problem is confined to strings u'\udbff\udc00' u'\U0010fc00'. Any help would be greatly appreciated. Bruce Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) [GCC 4.4.3] on linux2 u = map(unichr, xrange(56317, 56323)) [u'\udbfd', u'\udbfe', u'\udbff', u'\udc00', u'\udc01', u'\udc02'] .. length 6, ords(56317-56322) #-# # EXHIBIT 1: # # The following commands were used to write to file and then to read back # # to illustrate the effect of the substitute string on a file's size at # # least in Python 2.6.5 linux2(ubuntu 10.04), maybe other combinations. # # # # import codecs # # u = map(unichr, (xrange(56317, 56323)
How to parse a sentence using grammars provided by nltk?
Hi, When I define my own production rules for the grammar the code below runs fine. Can anyone tell me how to use the built in grammars of nltk (if there are any)? groucho_grammar = nltk.parse_cfg( ... S - NP VP ... PP - P NP ... NP - Det N | Det N PP | 'I' ... VP - V NP | VP PP ... Det - 'an' | 'my' ... N - 'elephant' | 'pajamas' ... V - 'shot' ... P - 'in' ... ) sent = ['I', 'shot', 'an', 'elephant', 'in', 'my', 'pajamas'] parser = nltk.ChartParser(groucho_grammar) trees = parser.nbest_parse(sent) for tree in trees: ... print tree thanks -- http://mail.python.org/mailman/listinfo/python-list
Extract stack from running python program
Is there a utility to extract the stacks from a running python program that is hung? Sounds like a long shot but if anyone knows it would be you guys. -- Zachary Burns (407)590-4814 Aim - Zac256FL Production Engineer Zindagi Games -- http://mail.python.org/mailman/listinfo/python-list
Re: Renaming OS files by file type in python
blur959 wrote: Hi all, I am creating a program that renames all files of the similar file type. But i am stuck at this part. I tried running this code and I got this error:new_name = os.rename(path, newpath) WindowsError: [Error 183] Cannot create a file when that file already exists. Hope you guys could help. [snip] As the traceback says, a file with that new name already exists. You can't have 2 files with the same name in the same folder. -- http://mail.python.org/mailman/listinfo/python-list
OptParse and Constant values
How do you use OptParse with constants?
Example:
usage = 'Usage: %prog [OPTIONS]'
parser = OptionParser(usage)
parser.add_option('-l','--level',
action='store_const',
default=LOG_INFO,
help='Set the log level to inject into syslog (either an\
integer [0 - 7] or one of LOG_EMERG, LOG_ALERT,LOG_CRIT,\
LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG')
(options,args) = parser.parse_args()
print options
always returns {'level':None} regarless of whether I call it with an
int (0 - 7) or the const name (LOG_*)
I'm importing syslog like so:
from syslog import *
so all the syslog constants should be available to me at run time (at
least that's my understanding) so I'm doing something wrong here or
just not understanding how to do a constant as an option.
The basic gist of the above is that I'm writing a tool to do basic
syslog testing by injecting messages and making sure they end up in
the correct log file... I can do all of this manually or in a loop by
looping through the various log levels, however, I want to be able to
specify them at run-time using an optional argument. Any ideas on how
to make this work, or at least why it's not doing what I thought it
would do?
Cheers
Jeff
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Re: OptParse and Constant values
On 8/12/10 11:19 AM, J wrote:
How do you use OptParse with constants?
Example:
usage = 'Usage: %prog [OPTIONS]'
parser = OptionParser(usage)
parser.add_option('-l','--level',
action='store_const',
default=LOG_INFO,
help='Set the log level to inject into syslog (either an\
integer [0 - 7] or one of LOG_EMERG, LOG_ALERT,LOG_CRIT,\
LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG')
(options,args) = parser.parse_args()
print options
always returns {'level':None} regarless of whether I call it with an
int (0 - 7) or the const name (LOG_*)
http://docs.python.org/library/optparse#standard-option-actions
'store_const' means that the option is a flag without arguments and stores the
value provided by the 'const' keyword to add_option() (it defaults to None so
that's what you get when you use that flag). This is not what you want. You just
want the default 'store' action.
--
Robert Kern
I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth.
-- Umberto Eco
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Re: Long rant about Python in Education
D'Arcy J.M. Cain da...@druid.net writes: On Thu, 12 Aug 2010 05:05:55 -0700 (PDT) เข้านอน iktomus.heyo...@gmail.com wrote: have to teach them to enjoy programming, enjoy computers, and develop their minds in a way that doesn't involve becoming 'Imams' who are essentially the learned mafia bosses of terrorism. This is the point that I stopped reading your message and added you to my blacklist. Goodbye. For what it's worth, same here. Also, I don't think it's a good idea to force a learning environment or an OS on a child. IMO it works best if you let the child discover and be a guide, not thou should not use Windows. Not so remarkable that the rant moves from an extremistic teaching environment to an extremistic world view. From hating everything that's not Linux and idolizing the CLI to hating everything that is different in general. -- John Bokma j3b Hacking Hiking in Mexico - http://johnbokma.com/ http://castleamber.com/ - Perl Python Development -- http://mail.python.org/mailman/listinfo/python-list
Re: unicode string alteration
BAvant Garde wrote: HELP!!! I need help with a unicode issue that has me stumped. I must be doing something wrong because I don't believe this condition would have slipped thru testing. Wherever the string u'\udbff\udc00' occurs u'\U0010fc00' or unichr(1113088) is substituted and the file loses 1 character resulting in all trailing characters being shifted out of position. No other corrupt strings have been detected. The condition was noticed while testing in Python 2.6.5 on Ubuntu 10.04 where the maximum ord # is 1114111 (wide Python build). Using Python 2.5.4 on Windows-ME where the maximum ord # is 65535 (narrow Python build) the string u'\U0010fc00' also occurs and it seems that the substitution takes place but no characters are lost and file sizes are ok. Note that ord(u'\U0010fc00') causes the following error: TypeError: ord() expected a character, but string of length 2 found The condition is otherwise invisible in 2.5.4 and is handled internally without any apparent effect on processing with characters u'\udbff' and u'\udc00' each being separately accessible. The first part of the attachment repeats this email but also has examples and illustrates other related oddities. Any help would be greatly appreciated. It's not an error, it's a surrogate pair. Surrogate pairs are part of the Unicode specification. Unicode codepoints go up to U+0010. If you're using 16 bits per codepoint, like in a narrow build of Python, then the codepoints above U+ _can't_ be represented directly, so they are represented by a pair of codepoints called a surrogate pair. If, on the other hand, you're using 32 bits per codepoint, like in a wide build of Python, then the codepoints above U+ _can_ be represented directly, so surrogate pairs aren't needed, and, indeed shouldn't be there. What you're seeing in the wide build is Python replacing a surrogate pair with the codepoint that it represents, which is actually the right thing to do because, as I said, the surrogate pairs really shouldn't be there. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why can't I set sys.ps1 to a unicode string?
In article i407mn$la...@online.de, Martin v. Loewis mar...@v.loewis.de wrote: So... why does having a non-ascii character in sys.ps1 make the prompt vanish? I can't pinpoint it to a specific line of code. Most likely, it tries to encode the prompt as ASCII before writing it to stdout. That fails, and it silently ignores the error. FWIW, this is fixed in Python 3. Guess it's time to upgrade. :-) Thanks! rg -- http://mail.python.org/mailman/listinfo/python-list
inline exception handling in python
Hi! I have on a few occasions now wanted to have inline-exception handling, like the inline if/else operator. For example, The following might raise ZeroDivisionError: f = n / d So, I can look before I leap (which is okay): f = float(nan) if d == 0 else n/d; But, what I'd like to be able to write is: f = n / d except float(nan); Which I find much more appealing than: try: f = n / d except: f = float(nan) (Obviously, I am thinking about more complicated functions than n/d -- but this works as an example.) Thoughts? W -- http://mail.python.org/mailman/listinfo/python-list
Re: OptParse and Constant values
On Thu, Aug 12, 2010 at 12:41, Robert Kern robert.k...@gmail.com wrote: On 8/12/10 11:19 AM, J wrote: How do you use OptParse with constants? http://docs.python.org/library/optparse#standard-option-actions 'store_const' means that the option is a flag without arguments and stores the value provided by the 'const' keyword to add_option() (it defaults to None so that's what you get when you use that flag). This is not what you want. You just want the default 'store' action. Thanks Robert... Sigh... head - desk - repeat :) -- http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
On Thursday 12 August 2010, it occurred to wheres pythonmonks to exclaim:
try:
f = n / d
except:
f = float(nan)
A catch-all except clause. Never a good idea. It's not as bad in this case, as
there is only one expression, but there are still a couple of other exceptions
that have a chance of occurring here: KeyboardInterrupt and SystemExit.
So:
try:
f = n / d
except ZeroDivisionError:
f = float('nan')
f = n / d except float(nan);
So this syntax really isn't adequate for real use: catch-all except clauses
are frowned upon, and rightfully so.
Besides, more often than not, you want to have a finally clause around when
you're dealing with exceptions.
(Obviously, I am thinking about more complicated functions than n/d
-- but this works as an example.)
The more complex the function is, the more likely it is to raise an exception
you can't handle that easily.
--
http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
On Thu, Aug 12, 2010 at 2:08 PM, Thomas Jollans tho...@jollybox.de wrote:
On Thursday 12 August 2010, it occurred to wheres pythonmonks to exclaim:
try:
f = n / d
except:
f = float(nan)
A catch-all except clause. Never a good idea. It's not as bad in this case, as
there is only one expression, but there are still a couple of other exceptions
that have a chance of occurring here: KeyboardInterrupt and SystemExit.
So:
try:
f = n / d
except ZeroDivisionError:
f = float('nan')
f = n / d except float(nan);
So this syntax really isn't adequate for real use: catch-all except clauses
are frowned upon, and rightfully so.
Besides, more often than not, you want to have a finally clause around when
you're dealing with exceptions.
(Obviously, I am thinking about more complicated functions than n/d
-- but this works as an example.)
The more complex the function is, the more likely it is to raise an exception
you can't handle that easily.
--
http://mail.python.org/mailman/listinfo/python-list
With a bit imagination the syntax can handle specific exceptions:
f = n /d except except(ZeroDivisionError) float(nan)
f = n /d except except(ZeroDivisionError) float(nan)
except(ValueError) float(nan)
But then we cannot bind to useful variable you say...
I think the problem in my case is best solved by look before you leap,
or a wrapper function. [I just hate function call overhead for this.
]
Thanks,
W
--
http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
On Thu, Aug 12, 2010 at 2:19 PM, wheres pythonmonks
wherespythonmo...@gmail.com wrote:
On Thu, Aug 12, 2010 at 2:08 PM, Thomas Jollans tho...@jollybox.de wrote:
On Thursday 12 August 2010, it occurred to wheres pythonmonks to exclaim:
try:
f = n / d
except:
f = float(nan)
A catch-all except clause. Never a good idea. It's not as bad in this case,
as
there is only one expression, but there are still a couple of other
exceptions
that have a chance of occurring here: KeyboardInterrupt and SystemExit.
So:
try:
f = n / d
except ZeroDivisionError:
f = float('nan')
f = n / d except float(nan);
So this syntax really isn't adequate for real use: catch-all except clauses
are frowned upon, and rightfully so.
Besides, more often than not, you want to have a finally clause around when
you're dealing with exceptions.
(Obviously, I am thinking about more complicated functions than n/d
-- but this works as an example.)
The more complex the function is, the more likely it is to raise an exception
you can't handle that easily.
--
http://mail.python.org/mailman/listinfo/python-list
With a bit imagination the syntax can handle specific exceptions:
f = n /d except except(ZeroDivisionError) float(nan)
f = n /d except except(ZeroDivisionError) float(nan)
except(ValueError) float(nan)
But then we cannot bind to useful variable you say...
I think the problem in my case is best solved by look before you leap,
or a wrapper function. [I just hate function call overhead for this.
]
Thanks,
W
I mean something along these lines:
f = n /d except(ZeroDivisionError) float(nan) except(ValueError) float(nan)
--
http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
Hi News123 Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? tnx Baba -- http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
wheres pythonmonks wrote: Hi! I have on a few occasions now wanted to have inline-exception handling, like the inline if/else operator. For example, The following might raise ZeroDivisionError: f = n / d So, I can look before I leap (which is okay): f = float(nan) if d == 0 else n/d; But, what I'd like to be able to write is: f = n / d except float(nan); Which I find much more appealing than: try: f = n / d except: f = float(nan) (Obviously, I am thinking about more complicated functions than n/d -- but this works as an example.) Thoughts? Discussed a year ago: [Python-Dev] (try-except) conditional expression similar to (if-else) conditional (PEP 308) http://code.activestate.com/lists/python-dev/90256/ -- http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
On Thu, Aug 12, 2010 at 2:42 PM, MRAB pyt...@mrabarnett.plus.com wrote: wheres pythonmonks wrote: Hi! I have on a few occasions now wanted to have inline-exception handling, like the inline if/else operator. For example, The following might raise ZeroDivisionError: f = n / d So, I can look before I leap (which is okay): f = float(nan) if d == 0 else n/d; But, what I'd like to be able to write is: f = n / d except float(nan); Which I find much more appealing than: try: f = n / d except: f = float(nan) (Obviously, I am thinking about more complicated functions than n/d -- but this works as an example.) Thoughts? Discussed a year ago: [Python-Dev] (try-except) conditional expression similar to (if-else) conditional (PEP 308) http://code.activestate.com/lists/python-dev/90256/ -- http://mail.python.org/mailman/listinfo/python-list http://code.activestate.com/lists/python-dev/90256/ Nice -- excellent discussion and what I was looking for. I am guessing that no implementation materialized. -- http://mail.python.org/mailman/listinfo/python-list
Re: inline exception handling in python
On Thursday 12 August 2010, it occurred to wheres pythonmonks to exclaim: [I just hate function call overhead for this.] I think you've got your priorities wrong. If you want to avoid unnecessary overhead, avoid exceptions more than functions. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
Baba wrote: def can_buy(n_nuggets): [snip] can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? You're calling the function, but you're not doing anything with the result. If you use print can_buy(55) you'll see the result on the console. Presumably you'll actually want to use it in an if statement. -- Brian -- http://mail.python.org/mailman/listinfo/python-list
Re: cx_Oracle 5.0.4 + Python 3.1.2 + Oracle Instant Client 10.2.04; DLL Load failed on import (Win/NT)
On Aug 12, 12:30 pm, Alexander Gattin xr...@yandex.ru wrote: Does Windows have anything like LD_LIBRARY_PATH/SHLIB_PATH? No, isn't that only if I have an actual Oracle client installed (not the instant client)? But great tip, wasn't exactly the solution, but your question triggered me to check the Windows environment variables*. I included env. variable name PATH and the value ;C:\Python31;C:\MinGW\bin;C:\TEMP \ORAIC10\bin. Only thing I set manually in the command prompt was: SET ORACLE_HOME=C: \TEMP\ORAIC10 , before the build. *=I checked the setup.py script which says: userOracleHome = os.environ.get(ORACLE_HOME) Checking in Visual Basic::environ(path) only included info from the Windows env. variables, and not the ones I set via the command prompt with PATH=%PATH%;... so I reckon if it applies to VB it also does for os.environ I can now import without errors! Thanks Alexander for putting me in the right direction. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Baba wrote: Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? First, the function gives up too early; it should only return False when all combinations of a, b, c (technically: the product of the ranges) have been tried. Second, can_buy(0) should return True, but the solution 0*6 + 0*9 + 0*20 is never tried; fix your ranges accordingly. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: urllib2 does not implement with Python 2.6
On 8/12/2010 1:34 AM, John Nagle wrote: Somewhat to my surprise, in Python 2.6, with urllib2.urlopen(url) as fh : doesn't work. It fails with AttributeError: addinfourl instance has no attribute '__exit__'. I thought that all the file-like objects supported with in 2.6. No? This seems to work in 3.1, which first came out almost a year after 2.6. from urllib.request import urlopen with urlopen(http://www.python.org;) as fh : pass -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: image resize doesn't work
In article mailman.1399.1280702057.1673.python-l...@python.org, Chris Hare ch...@labr.net wrote: And I see now what I did wrong - thanks for putting up with the questions. Posting that information is useful for any other newbies who might be following along -- Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/ ...if I were on life-support, I'd rather have it run by a Gameboy than a Windows box. --Cliff Wells -- http://mail.python.org/mailman/listinfo/python-list
Re: Inserting/Deleting newline(s) in very large text files
On Thursday 12 August 2010, it occurred to Dlanor Slegov to exclaim: Hi, I am dealing with very large text files (a few million lines) and would like to check and modify them according to a well defined format. The format requires ONLY ONE NEWLINE (followed by some sort of text) on top of the file and NO NEWLINE in the very end. The input files can be very diverse, such as one file may have 2 newlines on top and none in the end or other may not have a newline on top and 5 in the end. The aim is to check these files introduce JUST ONE NEWLINE in the TOP and NO NEWLINE in the BOTTOM. Any pointers will be appreciated. If the files are that long, you might want to avoid storing the whole file in memory at the same time. Have you already tried writing the program? If not, go write the program! (and then come back, possibly, if you have questions) PS: What a strange format that must be. Everybody agrees that text files should end with a line feed, because some text editors might mess up if they don't. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
Baba wrote: Hi News123 Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? Think about it this way. How many packs of 20 would you need? You don't want too many, but too few is OK. Then, how many packs of 9 for the remaining nuggets? (Again, you don't want too many.) Then, how many packs of 6? If all the nuggets are accounted for, good, otherwise reduce the number of one of the packs and try again. Repeat as necessary. A couple of 'for' loops will do it. -- http://mail.python.org/mailman/listinfo/python-list
Re: exception handling with sqlite db errors
In article 2a47b306-45d1-474a-9f8e-5b71eba62...@p11g2000prf.googlegroups.com,
CM cmpyt...@gmail.com wrote:
Maybe it's not much of an issue, but I think it would be a shame if
occasional hangs/crashes could be caused by these (rare?) database
conflicts if there is a good approach for avoiding them. I guess I
could put every last write to the db in a try/except block but I
thought there should be a more general solution, since that will
require many such exceptions and seems inelegant.
Wrap all your uses of sqlite into a function that does the try/except;
you only write the code once, then. As you progress, you can also
change the code to retry operations. Here's some ugly code I wrote on
top of SQLObject:
from sqlobject.dbconnection import registerConnection
from sqlobject.sqlite.sqliteconnection import SQLiteConnection
class RetrySQLiteConnection(SQLiteConnection):
Because SQLite is not really concurrent, having multiple processes
read/write can result in locked DB failures. In addition, SQLObject
doesn't properly protect operations in transations, so you can get
spurious DB errors claiming that the DB is corrupt because of
foreign key integrity failures.
This subclass retries DatabaseError and OperationalError
exceptions.
MAX_RETRIES = 4
SAFE_DB_ERROR = [
'database disk image is malformed',
'file is encrypted or is not a database',
]
def _safe_db_error(self, exception):
err = str(exception).lower()
for safe_err in self.SAFE_DB_ERROR:
if safe_err in err:
return True
return False
def _check_integrity(self):
conn = self.getConnection()
try:
i = 0
while True:
i += 1
try:
cursor = conn.cursor()
query = pragma integrity_check
SQLiteConnection._executeRetry(self, conn, cursor, query)
result = cursor.fetchall()
if result == [('ok',)]:
return True
else:
logging.error(Bad integrity result: %s, result)
return False
except DatabaseError, e:
if i self.MAX_RETRIES:
logging.info('integrity_check, try #%s: %s', i, e)
time.sleep(2)
else:
logging.error('integrity_check, try #%s: %s', i, e)
raise
finally:
self.releaseConnection(conn)
def _executeRetry(self, conn, cursor, query):
i = 0
while True:
i += 1
try:
return SQLiteConnection._executeRetry(self, conn, cursor, query)
except OperationalError, e:
if i self.MAX_RETRIES:
logging.warn('OperationalError, try #%s: %s', i, e)
time.sleep(10)
else:
logging.error('OperationalError, try #%s: %s', i, e)
raise
except DatabaseError, e:
if e.__class__ is not DatabaseError:
# Don't retry e.g. IntegrityError
raise
if not self._safe_db_error(e):
# Only retry specific errors
raise
if not self._check_integrity():
raise
if i self.MAX_RETRIES:
logging.warn('DatabaseError, try #%s: %s', i, e)
time.sleep(0.5)
else:
logging.error('DatabaseError, try #%s: %s', i, e)
raise
def conn_builder():
return RetrySQLiteConnection
registerConnection(['retrysqlite'], conn_builder)
def init():
dbpath = os.path.join(common.getSyncDataPath(), app.dbname)
connection_string = retrysqlite: + dbpath
global _connection
_connection = connectionForURI(connection_string)
--
Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/
...if I were on life-support, I'd rather have it run by a Gameboy than a
Windows box. --Cliff Wells
--
http://mail.python.org/mailman/listinfo/python-list
Re: Line-by-line processing when stdin is not a tty
On Wed, 11 Aug 2010 18:49:26 -0700, RG wrote: This doesn't explain why cat | cat when run interactively outputs line-by-line (which it does). STDIN to the first cat is a TTY, but the second one isn't. GNU cat doesn't use stdio, it uses read() and write(), so there isn't any buffering. For more complex programs, using unbuffered I/O may not be practical, due to either code complexity or performance. -- http://mail.python.org/mailman/listinfo/python-list
Re: Announcing: python-ghostscript 0.3
In article alpine.deb.1.10.1008121733280.3...@localhost,
Peter Kleiweg p.c.j.klei...@rug.nl wrote:
Hartmut Goebel schreef op de 12e dag van de oogstmaand van het jaar 2010:
Here is an example for how to use the high-level interface of
`python-ghostscript`. This implements a very basic ps2pdf-tool::
import sys
import ghostscript
args = [
ps2pdf, # actual value doesn't matter
-dNOPAUSE, -dBATCH, -dSAFER,
-sDEVICE=pdfwrite,
-sOutputFile= + sys.argv[1],
-c, .setpdfwrite,
-f, sys.argv[2]
]
ghostscript.Ghostscript(*args)
How is this different from os.system(' '.join(args)) ?
You don't have problems with shell metacharacters.
--
Aahz (a...@pythoncraft.com) * http://www.pythoncraft.com/
...if I were on life-support, I'd rather have it run by a Gameboy than a
Windows box. --Cliff Wells
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why can't I set sys.ps1 to a unicode string?
On Thursday 12 August 2010, it occurred to RG to exclaim: %%% /%%% If this were a properly unicode-enabled newsreader you would see a yin-yang symbol in the middle of s2. Are you sure about that? Now maybe the mailing list gateway is messing things up, but I rather suspect your newsreader (or USENET server) is sending out nonsense. After all, Unicode usually works around here. Some excerpts from the message, as I received it: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit [...] print s2 %%% /%%% No quoted-printable. No UTF-7. Just three completely random characters? -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Aug 12, 2010, at 9:02 PM, Peter Otten wrote: Baba wrote: Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? First, the function gives up too early; it should only return False when all combinations of a, b, c (technically: the product of the ranges) have been tried. Second, can_buy(0) should return True, but the solution 0*6 + 0*9 + 0*20 is never tried; fix your ranges accordingly. Moreover: a, b and c can range over n_nuggets/6, n_nuggets/9 and n_nuggets/20 respectively. This will work, but does too much work. Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
On 08/11/10 21:14, Baba wrote: cut How about rephrasing that question in your mind first, i.e.: For every number that is one higher then the previous one*: If this number is dividable by: 6 or 9 or 20 or any combination of 6, 9, 20 than this number _can_ be bought in an exact number else print this number * There are an infinite amount of numbers, just imagine the biggest number you can think of and I say plus 1 :-) Next thing you have to do is figure out how to write this in python, particularly getting all the combinations of divisions can be tricky. Hint; you are not really interested in the division result but rather if a division would be complete or give a remainder (modulo operator). If you get an remainder this could be okay if that can divided by one of the other numbers, and so forth till you ran out of combinations. -- mph -- http://mail.python.org/mailman/listinfo/python-list
Re: Announcing: python-ghostscript 0.3
Aahz schreef op de 12e dag van de oogstmaand van het jaar 2010:
In article alpine.deb.1.10.1008121733280.3...@localhost,
Peter Kleiweg p.c.j.klei...@rug.nl wrote:
Hartmut Goebel schreef op de 12e dag van de oogstmaand van het jaar 2010:
Here is an example for how to use the high-level interface of
`python-ghostscript`. This implements a very basic ps2pdf-tool::
import sys
import ghostscript
args = [
ps2pdf,# actual value doesn't matter
-dNOPAUSE, -dBATCH, -dSAFER,
-sDEVICE=pdfwrite,
-sOutputFile= + sys.argv[1],
-c, .setpdfwrite,
-f, sys.argv[2]
]
ghostscript.Ghostscript(*args)
How is this different from os.system(' '.join(args)) ?
You don't have problems with shell metacharacters.
Then use os.spawnv(os.P_WAIT, args[0], args)
--
Peter Kleiweg L:NL,af,da,de,en,ia,nds,no,sv,(fr,it) S:NL,de,en,(da,ia)
info: http://www.let.rug.nl/kleiweg/ls.html
--
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Re: inline exception handling in python
On Thu, Aug 12, 2010 at 2:57 PM, Thomas Jollans tho...@jollybox.de wrote: On Thursday 12 August 2010, it occurred to wheres pythonmonks to exclaim: [I just hate function call overhead for this.] I think you've got your priorities wrong. If you want to avoid unnecessary overhead, avoid exceptions more than functions. -- http://mail.python.org/mailman/listinfo/python-list Well I suppose it matters depending on the nature of the data you are looking at... But small function calls tend to be the death of interpreted languages... timeit.timeit( def f(y,i): try: return(y/(i%10)) except: return(float(nan)) for i in range(100): x = f(7,i) ) 56.362180419240985 timeit.timeit( for i in range(100): try: x = 7 / (i % 10) except: x = float(nan) ) 34.588313601484742 -- http://mail.python.org/mailman/listinfo/python-list
Decompressing a file retrieved by URL seems too complex
I'm reading a URL which is a .gz file, and decompressing it. This works, but it seems far too complex. Yet none of the wrapping you might expect to work actually does. You can't wrap a GzipFile around an HTTP connection, because GzipFile, reasonably enough, needs random access, and tries to do seek and tell. Nor is the output descriptor from gzip general; it fails on readline, but accepts read. (No good reason for that.) So I had to make a second copy. John Nagle def readurl(url) : if url.endswith(.gz) : nd = urllib2.urlopen(url,timeout=TIMEOUTSECS) td1 = tempfile.TemporaryFile() # compressed file td1.write(nd.read())# fetch and copy file nd.close() # done with network td2 = tempfile.TemporaryFile() # decompressed file td1.seek(0) # rewind gd = gzip.GzipFile(fileobj=td1, mode=rb) # wrap unzip td2.write(gd.read()) # decompress file td1.close() # done with compressed copy td2.seek(0) # rewind return(td2) # return file object for compressed object else : return(urllib2.urlopen(url,timeout=TIMEOUTSECS)) -- http://mail.python.org/mailman/listinfo/python-list
EXOR or symmetric difference for the Counter class
I find myself needing to calculate the difference between two Counters
or multisets or bags.
I want those items that are unique to each bag. I know how to
calculate it:
b = Counter(a=1, b=2)
c = Counter(a=3, b=1)
diff = (b - c) + (c - b)
(b - c)
Counter({'b': 1})
(c - b)
Counter({'a': 2})
diff
Counter({'a': 2, 'b': 1})
But thought why doesn't this operation appear already as a method of
the class?
- Paddy.
--
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Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Hi Baba, The last tips should really help you getting started: for testing your function you could do: Below your uncorrected code and a test for it def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): print trying for %2d: %2d %2d %2d % (n,a,b,c) if 6*a+9*b+20*c==n_nuggets: return True else: return False # show the results for the first 50 numbers. for n in xrange(50): result = can_buy(n) # get the result (see Brian's comment) print(result of can_buy(%2d) is %s % (n,result)) with the print statement in can_buy() you should immediately see some issues. as soon as can_buy seems to work, you could comment the print statement. Additionally: I would return [a,b,c] if you got a result and [] if you got no result. So you don't only seem whether you can buy n nuggets, but you can also see how (AND even verify the solution) the print statement should show you what Peter said. You just make one test and return immediately in the else statement Instead you should continue until you found a solution or until you tried all possibilities. After having fixed the fact, that you don't try all options, you'll see that your first success would be with 6+9+12 = 27 nuggets es you never try with 0 boxes of a kind. (as Peter mentioned) Finally as Roald says. if you can reduce the upper limit of your search ranges. if you have for example 13 nuggets you do not have to try 3 boxes of 6 as this is already 18, so trying only 0,1 or two boxes is enough You will now also see, what On 08/12/2010 09:42 PM, Roald de Vries wrote: On Aug 12, 2010, at 9:02 PM, Peter Otten wrote: Baba wrote: Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? First, the function gives up too early; it should only return False when all combinations of a, b, c (technically: the product of the ranges) have been tried. Second, can_buy(0) should return True, but the solution 0*6 + 0*9 + 0*20 is never tried; fix your ranges accordingly. Moreover: a, b and c can range over n_nuggets/6, n_nuggets/9 and n_nuggets/20 respectively. This will work, but does too much work. Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: default behavior
Peter Otten __pete...@web.de wrote: 1 .conjugate() This is a syntax I never noticed before. My built-in complier (eyes) took one look and said: that doesn't work. Has this always worked in Python but I never noticed? I see other instance examples also work. '1' .zfill(2) '01' 1.0 .is_integer() True and properties 1.0 .real 1.0 Curiously, this works -- http://mail.python.org/mailman/listinfo/python-list
Re: shelf-like list?
On Tuesday 10 August 2010, it occurred to kj to exclaim: I'm looking for a module that implements persistent lists: objects that behave like lists except that all their elements are stored on disk. IOW, the equivalent of shelves, but for lists rather than a dictionaries. Does anyone know of such a module? (I suppose that I could slap together a crude implementation of such a thing by wrapping a shelf with suitable methods to simulate the list interface. But I'd rather not roll my own if a tested implementation already exist.) You could simply use pickle to save the data every once in a while. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
One more small tip to verify whether your code is working: On 08/12/2010 10:28 PM, News123 wrote: Hi Baba, Your code, but returning the result as suggested in my preious post: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): print trying for %2d: %2d %2d %2d % (n,a,b,c) if 6*a+9*b+20*c==n_nuggets: return [a,b,c] else: return [] # show the results for the first 50 numbers. # and verify whether it's true for n in xrange(50): result = can_buy(n) # get the result (see Brian's commen print(result of can_buy(%2d) is %s % (n,result)) if result: a,b,c = result if a*6+b*9+c*12 != n: print ERROR: can_buy() gives wrong result Alternatively you can use a nice python feature called asserts assert statements can be used to vrify whether your code works as expected. Nothing will be printed if the assertion is correct otherwise your program will abort and print the assertion error: Example: for n in xrange(50): result = can_buy(n) # get the result (see Brian's commen print(result of can_buy(%2d) is %s % (n,result)) if result: a,b,c = result assert a*6+b*9+c*12 == n with the print statement in can_buy() you should immediately see some issues. as soon as can_buy seems to work, you could comment the print statement. Additionally: I would return [a,b,c] if you got a result and [] if you got no result. So you don't only seem whether you can buy n nuggets, but you can also see how (AND even verify the solution) the print statement should show you what Peter said. You just make one test and return immediately in the else statement Instead you should continue until you found a solution or until you tried all possibilities. After having fixed the fact, that you don't try all options, you'll see that your first success would be with 6+9+12 = 27 nuggets es you never try with 0 boxes of a kind. (as Peter mentioned) Finally as Roald says. if you can reduce the upper limit of your search ranges. if you have for example 13 nuggets you do not have to try 3 boxes of 6 as this is already 18, so trying only 0,1 or two boxes is enough You will now also see, what On 08/12/2010 09:42 PM, Roald de Vries wrote: On Aug 12, 2010, at 9:02 PM, Peter Otten wrote: Baba wrote: Thank You for helping me out. Indeed i am not looking for the code but rather for hints that direct my reasoning as well as hints as to how to write basic programs like this. You have broken down the approach into 2 parts. I have tried to solve part 1 but i'm not quite there yet. Here's my code: def can_buy(n_nuggets): for a in range (1,n_nuggets): for b in range (1,n_nuggets): for c in range (1,n_nuggets): if 6*a+9*b+20*c==n_nuggets: #print a,b,c,'n_nuggets=',n_nuggets return True else: return False can_buy(55) as you can see i am trying to loop through all combinations of values bewtween 1 and n_nuggets and when the equation resolves it should return True, else it should return False. I was hoping that when i then call my function and ask it to test a value nothing happens. What is wrong? My syntax? My semantic? Both? First, the function gives up too early; it should only return False when all combinations of a, b, c (technically: the product of the ranges) have been tried. Second, can_buy(0) should return True, but the solution 0*6 + 0*9 + 0*20 is never tried; fix your ranges accordingly. Moreover: a, b and c can range over n_nuggets/6, n_nuggets/9 and n_nuggets/20 respectively. This will work, but does too much work. Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: default behavior
[Oops, now complete...] Peter Otten __pete...@web.de wrote: 1 .conjugate() This is a syntax I never noticed before. My built-in complier (eyes) took one look and said: that doesn't work. Has this always worked in Python but I never noticed? I see other instance examples also work. '1' .zfill(2) '01' 1.0 .is_integer() True and properties 1.0 .real 1.0 Curiously, a float literal works without space 1.0.conjugate() 1.0 but not an int. 1.conjugate() File stdin, line 1 1.conjugate() ^ SyntaxError: invalid syntax Anyway, I didn't realize int has a method you can call. --David -- http://mail.python.org/mailman/listinfo/python-list
Floating numbers
Hi all. Is there a way I can keep my floating point number as I typed it? For example, I want 34.52 to be 34.52 and NOT 34.520002. -- Bradley J. Hintze Graduate Student Duke University School of Medicine 801-712-8799 -- http://mail.python.org/mailman/listinfo/python-list
Decompressing a file retrieved by URL seems too complex
(Repost with better indentation) I'm reading a URL which is a .gz file, and decompressing it. This works, but it seems far too complex. Yet none of the wrapping you might expect to work actually does. You can't wrap a GzipFile around an HTTP connection, because GzipFile, reasonably enough, needs random access, and tries to do seek and tell. Nor is the output descriptor from gzip general; it fails on readline, but accepts read. (No good reason for that.) So I had to make a second copy. John Nagle def readurl(url) : if url.endswith(.gz) : nd = urllib2.urlopen(url,timeout=TIMEOUTSECS) td1 = tempfile.TemporaryFile() # compressed file td1.write(nd.read())# fetch and copy file nd.close() # done with network td2 = tempfile.TemporaryFile() # decompressed file td1.seek(0) # rewind gd = gzip.GzipFile(fileobj=td1, mode=rb) # wrap unzip td2.write(gd.read()) # decompress file td1.close() # done with compressed copy td2.seek(0) # rewind return(td2) # return file object for compressed object else : return(urllib2.urlopen(url,timeout=TIMEOUTSECS)) -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6,9 and 20
On 08/12/2010 09:56 PM, Martin P. Hellwig wrote: On 08/11/10 21:14, Baba wrote: cut How about rephrasing that question in your mind first, i.e.: For every number that is one higher then the previous one*: If this number is dividable by: 6 or 9 or 20 or any combination of 6, 9, 20 than this number _can_ be bought in an exact number else print this number you are allowed to mix. 15 is neither divisable by 6 nor by nine, but 9 + 6 = 15 I guess, trying to find the result with divisions and remainders is overly complicated. Simple brute force trial to find a combination shall be enough. Also: if you know for example, that you can buy 101,102,103,104,105 and 106 nuggets, then you know, that you can buy any other larger amout of nuggets. 107 = 101 + one box of six 108 = 102 + one box of six . . . As soon as you found 6 sequential solutions you can stop searching. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On 8/12/2010 9:22 AM, Dave Angel wrote: Now you have to find the largest number below 120, which you can easily do with brute force Dept of overkill, iterators/generators division ... -John #-- from itertools import imap, product, ifilter from operator import mul box_sizes = (6, 9, 20) def sum_product(s1, s2): return scalar product of two sequences return sum(imap(mul, s1, s2)) def reachables(target): return generator of numbers that are = target and are valid linear combos of McNuggets candidate_box_counts = product( xrange(target/box_sizes[0] + 1), xrange(target/box_sizes[1] + 1), xrange(target/box_sizes[2] + 1), ) gen = (sum_product(box_sizes, tup) for tup in candidate_box_counts) return (ifilter(lambda val, tgt=target: val tgt, gen)) if __name__ == __main__: tgt = 120 # thanks, Dave Angel unreachables = set(xrange(tgt)) - set(reachables(tgt)) print Max unreachable:, max(unreachables) -- http://mail.python.org/mailman/listinfo/python-list
Re: default behavior
David Niergarth wrote: [Oops, now complete...] Peter Otten __pete...@web.de wrote: 1 .conjugate() This is a syntax I never noticed before. My built-in complier (eyes) took one look and said: that doesn't work. (1).conjugate may hurt a little less. Anyway, the space is only needed for the tokenizer that without it would produce a float immediately followed by a name. Has this always worked in Python but I never noticed? Probably. I see other instance examples also work. '1' .zfill(2) '01' 1.0 .is_integer() True and properties 1.0 .real 1.0 Curiously, a float literal works without space 1.0.conjugate() 1.0 but not an int. 1.conjugate() File stdin, line 1 1.conjugate() ^ SyntaxError: invalid syntax Anyway, I didn't realize int has a method you can call. --David -- http://mail.python.org/mailman/listinfo/python-list
re.sub and variables
I have a function that I am attempting to call from another file. I am attempting to replace a string using re.sub with another string. The problem is that the second string is a variable. When I get the output, it shows the variable name rather than the value. Is there any way to pass a variable into a regex? If not, is there any other way to do this? I need to be able to dump the variable value into the replacement string. For what it's worth this is an XML file so I'm not afraid to use some sort of XML library but they look fairly complicated for a newbie like me. Also, this is py3.1.2 is that makes any difference. Thanks!!! # import random import re import datetime def pop_time(some_string, start_time): global that_string rand_time = random.randint(0, 30) delta_time = datetime.timedelta(seconds=rand_time) for line in some_string: end_time = delta_time + start_time new_string = re.sub(thisstring, thisstring\\end_time, some_string) start_time = end_time return new_string -- http://mail.python.org/mailman/listinfo/python-list
Re: Floating numbers
On 08/12/2010 01:43 PM, Bradley Hintze wrote: Hi all. Is there a way I can keep my floating point number as I typed it? For example, I want 34.52 to be 34.52 and NOT 34.520002. Is this a Python question? The answer is both Yes and No. The binary floating point representation of numbers on a computer cannot exactly represent most decimal number you would like to type. (Similar to the fact that you cannot represent 1/3 exactly in a decimal system.) But that's the internal representation, over which you have no control. You do, however, have control over how a number is displayed when printed. Python 2: Choose a format that displays the exact number of digits you want '%.2f' % a or let str(a) choose but not repr(a) which tries to get all the digits. (Adding to the confusion, you might also find it confusing to understand which of str() or repr() Python chooses to display a number.) Python 3: Python3 uses David Gay’s algorithm for chosing how to display floats. Both str(a) and repr(a) produce '34.52' for your example, which is probably just what you want. Gary Herron -- http://mail.python.org/mailman/listinfo/python-list
Re: Floating numbers
On 2010-08-12, Bradley Hintze bradle...@aggiemail.usu.edu wrote: Is there a way I can keep my floating point number as I typed it? No. For example, I want 34.52 to be 34.52 and NOT 34.520002. You can't represent 34.52 using base-2 IEEE floating point (the HW floating point format used by pretty much all modern computers). 34.520002 is as close as you can get. When you enter a base-10 floating-point number, the computer will use the closest base-2 IEEE floating point number. Here are the nitty-gritty details: http://docs.sun.com/source/806-3568/ncg_goldberg.html Can you explain what your actual problem is? -- Grant Edwards grant.b.edwardsYow! I'm imagining a surfer at van filled with soy sauce! gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Floating numbers
On 2010-08-12, Grant Edwards inva...@invalid.invalid wrote: On 2010-08-12, Bradley Hintze bradle...@aggiemail.usu.edu wrote: Is there a way I can keep my floating point number as I typed it? No. For example, I want 34.52 to be 34.52 and NOT 34.520002. You can't represent 34.52 using base-2 IEEE floating point (the HW floating point format used by pretty much all modern computers). 34.520002 is as close as you can get. When you enter a base-10 floating-point number, the computer will use the closest base-2 IEEE floating point number. Here are the nitty-gritty details: http://docs.sun.com/source/806-3568/ncg_goldberg.html Here is a gentler intro: http://pyfaq.infogami.com/why-are-floating-point-calculations-so-inaccurate -- Grant Edwards grant.b.edwardsYow! If I felt any more at SOPHISTICATED I would DIE gmail.comof EMBARRASSMENT! -- http://mail.python.org/mailman/listinfo/python-list
