Re: Obtaining a full path name from file
RVince wrote: > s = "C:\AciiCsv\Gravity_Test_data\A.csv" > f = open(s,"r") > > How do I obtain the full pathname given the File, f? Apart from the issue that the 'name' attribute is only the name used to open the file, there is another issue, though not on the platform you're using: Multiple directory entries can point to the same file, all of which can be changed (including deletion!) even while you have the file open. I'm not sure what problem you're trying to solve, but I'm afraid your approach is at least limited. Good luck! Uli -- Domino Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Review
ad wrote:
> Please review the code pasted below. I am wondering what other ways
> there are of performing the same tasks. This was typed using version
> 3.2. The script is designed to clean up a directory (FTP, Logs, etc.)
> Basically you pass two arguments. The first argument is an number of
> days old to delete. The second argument is the directory where the
> files and folders should be deleted. I imagine one enhancement would
> be to create a function out of some of this.
> CurrentTime = time.time()
Read PEP 8 on naming conventions etc., see
http://python.org/dev/peps/pep-0008/
>
> epocDay = 86400 # seconds
>
>
>
>
>
> parser = argparse.ArgumentParser(description = "Delete files and
What's the purpose of those many empty lines?
> folders in a directory N days old", add_help=False,
> prog='directorycleaner', usage='%(prog)s 7 c:\\temp')
>
> parser.add_argument('days', type=int, help="Numeric value: delete
> files and folders older then N days")
>
> parser.add_argument('directory', help="delete files and folders in
> this directory")
>
> parser.print_help()
What's the idea behind add_help=False and the explicit print_help()?
> dictKeys = (vars(args))
> HowManyDays = dictKeys['days']
This can be simplified to
HowManyDays = args.days
> if dirExists == False: print ("The directory is missing")
if x == False: ...
is normally written as
if not x: ...
> DirListing = os.listdir(WhatDirectory)
> for files in DirListing:
You might write this as
for filename in os.listdir(WhatDirectory): ...
or even
for filename in os.listdir(args.directory): ...
Personally I would put this stuff in a separate function like
def remove_old_files_and_folders(parent_directory, age_in_seconds):
...
> # time.ctime converts epoch to a normal date
>
> #print (time.ctime(CurrentTime))
>
> # Get the date from seven days ago
>
> WeekOldFileDate = CurrentTime - DaysToDelete
>
> #print (CurrentTime)
>
> #print (FileCreationTime)
>
> #print (WeekOldFileDate)
Don't let out-commented code eclipse the actual code; remove it. If you want
to preserve it for eternity, have a look at version control systems, e. g.
Mercurial.
--
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Re: Obtaining a full path name from file
On 25/05/2011 07:36, Ulrich Eckhardt wrote: RVince wrote: s = "C:\AciiCsv\Gravity_Test_data\A.csv" f = open(s,"r") How do I obtain the full pathname given the File, f? Apart from the issue that the 'name' attribute is only the name used to open the file, there is another issue, though not on the platform you're using: Multiple directory entries can point to the same file, all of which can be changed (including deletion!) even while you have the file open. FWIW that's true even on Windows. (Although arguably less common). I'm not sure what problem you're trying to solve, but I'm afraid your approach is at least limited. Depends on what the requirement is. If it is, essentially: "give me at least one of the names this file had when I opened it", then this approach is surely adequate. Certainly, things could have happened in the meantime. Obviously, only the OP can know the circumstances he's dealing with, but ISTM that far and away the most common case will be that the file has exactly one name and that it hasn't changed. TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: English Idiom in Unix: Directory Recursively
* Rikishi42 (Wed, 25 May 2011 00:06:06 +0200) > > On 2011-05-24, Steven D'Aprano wrote: > >>> I think that is a patronizing remark that under-estimates the > >>> intelligence of lay people and over-estimates the difficulty of > >>> understanding recursion. > >> > >> Why would you presume this to be related to intelligence? The point was > >> not about being *able* to understand, but about *needing* to understand > >> in order to use. > > > > Maybe they don't "need" to understand recursion. So what? > > I think you should read the earlier posts again, this is drifting so far > from what I intended. > > What I mean is: I'm certain that over the years I've had more than one > person come to me and ask what 'Do you wish to delete this directory > recursively?' meant. BAut never have I been asked to explain what 'Do you > wish to delete this directory and it's subdirs/with all it's contents?' > meant. Never. Naming something in the terms of its implementation details (in this case recursion) is a classical WTF. On the other hand, it's by far not the only WTF in Unix. For instance, how often have you read "unlink" instead of "delete"? Or "directory" instead of "folder", pointing out that "directory" is the correct term because a directory is just a listing and does not "contain" the actual files. Of course these implementation details will never matter to anyone except under the rarest conditions. Thorsten -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
* Chris Angelico (Wed, 25 May 2011 08:01:38 +1000) > > On Wed, May 25, 2011 at 3:39 AM, D'Arcy J.M. Cain wrote: > > One of my favorite quotes (not sure if it was about Perl or APL) is "I > > refuse to use a programming language where the proponents of it stick > > snippets under each other's nose and say 'I bet you can't guess what > > this does.'" > > Yes, I believe that was Perl. And an amusing quote. But most of the > point of it comes from the fact that Perl uses punctuation for most of > its keywords, whereas (say) Python uses English words; it's a lot more > fun to crunch something down when you can use $| and friends than when > you have to put "x and y", complete with spaces, for a simple boolean. > But that says nothing about which language is actually better for > working with... [...] It does say something about readibility. And yes, "readability counts". And yes, readability says a lot about how good a language is for reading and working with. Thorsten -- http://mail.python.org/mailman/listinfo/python-list
Re: File access denied after subprocess completion on Windows platform
On 24/05/2011 21:18, Claudiu Nicolaie CISMARU wrote: Now. There is one more issue. Seems that on faster computers and/or Windows 7 (the Win32 thing I have tested on a HVM Xen machine with Windows XP) the os.rename is too fast after fp.close() and generates the same Exception. The code follows: curl.close() fp.close() os.rename(tfile, actualfile) Where, tfile is the .part file, actual file is the real destination, fp was opened with open(..., "wb") and the descriptor passed to curl. I have solved the issue with self.msleep(10) - msleep is a method of QThread. But I don't think it's an elegant and normal solution. Did fp.close() is delayed, or? I mean, I don't want to rely on a "sleep" in order to workaround the access issue. There used to be a problem with subprocess fds being held by a traceback. IIRC, the problem could be triggered by having an except clause around a subprocess call within which something attempted to, eg, remove one of the affected files. I'm sorry if that's a bit of a woolly description but if you think this might be biting you I'll dive in and look at the code. What version of Python are you using? (That said, the fact that the behaviour varies between faster and slower computers makes that cause unlikely. Maybe we're back to looking at virus checkers and the like...) TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Review
In article
<37ba7b40-3663-4094-b507-696fc598b...@l26g2000yqm.googlegroups.com>
ad wrote:
>Please review the code pasted below. I am wondering what other ways
>there are of performing the same tasks. ... I imagine one enhancement
>would be to create a function out of some of this.
Indeed -- "recommended styles" include defining a main()
function and calling main at the bottom, e.g., with:
if __name__ == '__main__':
main()
or:
if __name__ == '__main__':
main(sys.argv)
Something has also double-spaced your code; I will undo that below.
>import os
>import time
>import shutil
>import argparse
So far so good.
Let me start by putting the next parts into main(). I will use
the no-argument format since we can simply let parser.parse_args()
fetch sys.argv the same way you did (we could def main(argv) and
pass argv; this is sometimes useful for testing purposes, but here
it makes little difference one way or another).
def main():
>CurrentTime = time.time()
>epocDay = 86400 # seconds
(You could write 24 * 60 * 60, but again this is sort of a six-of-one
half-a-dozen-of-the-other situation.) What is not clear is why you
are setting these now, rather than later, closer to where they are
going to be used.
Many style guides, including Guido's and pylint's, dislike
UppercaseVariableName and camelCase style names within functions.
(UppercaseNames are reserved to classes.) I am leaving these alone
for now though.
>parser = argparse.ArgumentParser(description = "Delete files and
>folders in a directory N days old", add_help=False,
>prog='directorycleaner', usage='%(prog)s 7 c:\\temp')
Line wrap has done bad things to this. Still, there is something
odd about it other than the line wrap:
- sometimes you write:
param_name = value
but sometimes you use:
param_name=value
and in one case you even use both:
usage= [string]
- you switch back and forth between single and double quoted
strings, without much reason.
Consistency is not *required* but it is generally a good idea.
(This is also minor, like deciding between 86400 or 24*60*60.
Eventually, though, lots of minor things add up.)
(I have to admit here that I tend to switch back and forth on
quotes too. :-) )
Another "sixes" case occurs here with the backslashes: to get
a literal backslash in a string, you can use "raw strings". Here
it makes no difference but I will go ahead and do it just for
illustration:
parser = argparse.ArgumentParser(
description='Delete files and folders in a directory N days old',
add_help=False,
prog='directorycleaner',
usage=r'%(prog)s 7 c:\temp')
Finally, I am not sure why you do not want to allow a -h / --help
option (but if you take out the add_help=False, it's probably best
to take out the call to parser.print_help() too), and there is no
need to supply a usage= argument at all -- argparse() will build
one for you.
>parser.add_argument('days', type=int, help="Numeric value: delete
>files and folders older then N days")
>parser.add_argument('directory', help="delete files and folders in
>this directory")
(Again, line wrap has broken these; the fixes are obvious so I skip
over them here.)
>parser.print_help()
>args = parser.parse_args()
(So far so good, although again, you probably want to remove the call
to print_help() if you allow argparse to add a -h / --help option,
at least.)
>dictKeys = (vars(args))
There is no *need* to do this, although it is documented as allowed.
I prefer to just use args. myself:
>HowManyDays = dictKeys['days']
>WhatDirectory = dictKeys['directory']
so this would become:
HowManyDays = args.days
WhatDirectory = args.directory
>print (HowManyDays)
>print (WhatDirectory)
These are presumably debug statements and should be removed, but
until then, it might be good to prefix the output with what is
being printed (i.e., a debug message). (I have taken them out
of my copy, for output shown below.)
(In a fancier program, you could use the logging module and
logging.debug().)
>DaysToDelete = HowManyDays * epocDay
Right before this would be a good place to create epocDay.
>dirExists = os.path.exists(WhatDirectory)
>if dirExists == False: print ("The directory is missing")
An explicit "if expr == False" is generally a bad idea -- if an
expression can be "considered boolean" (and the return value of
os.path.exists certainly can), just write "if not expr".
Most style guides suggest putting subsequent statements on new
lines, rather than right after the ":".
Checking that the directory exists seems reasonable enough. However,
after printing that it does not, you continue on with code that is
going to immediately raise an OSError exception:
>DirListing = os.listdir(WhatDirectory)
In general, it is better to try to do the operation, and catch the
failure and do something about it at that point, than t
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Re: English Idiom in Unix: Directory Recursively
On May 25, 12:26 am, Thorsten Kampe wrote: > * Rikishi42 (Wed, 25 May 2011 00:06:06 +0200) > > > > > > > > > > > > > On 2011-05-24, Steven D'Aprano wrote: > > >>> I think that is a patronizing remark that under-estimates the > > >>> intelligence of lay people and over-estimates the difficulty of > > >>> understanding recursion. > > > >> Why would you presume this to be related to intelligence? The point was > > >> not about being *able* to understand, but about *needing* to understand > > >> in order to use. > > > > Maybe they don't "need" to understand recursion. So what? > > > I think you should read the earlier posts again, this is drifting so far > > from what I intended. > > > What I mean is: I'm certain that over the years I've had more than one > > person come to me and ask what 'Do you wish to delete this directory > > recursively?' meant. BAut never have I been asked to explain what 'Do you > > wish to delete this directory and it's subdirs/with all it's contents?' > > meant. Never. > > Naming something in the terms of its implementation details (in this > case recursion) is a classical WTF. > > On the other hand, it's by far not the only WTF in Unix. For instance, > how often have you read "unlink" instead of "delete"? Or "directory" > instead of "folder", pointing out that "directory" is the correct term > because a directory is just a listing and does not "contain" the actual > files. Of course these implementation details will never matter to > anyone except under the rarest conditions. > > Thorsten well said. half of posts in this thread are from idiots. just incredible, but again, its newsgroups ... what am i thinking ... Xah -- http://mail.python.org/mailman/listinfo/python-list
Re: English Idiom in Unix: Directory Recursively
On Wed, May 25, 2011 at 5:51 PM, Xah Lee wrote: > well said. > > half of posts in this thread are from idiots. just incredible, but > again, its newsgroups ... what am i thinking ... > > Xah > Thank you. As soon as we figure out which half of us you just publicly insulted, we'll see about getting offended. Until then, thank you for your contribution and please, have a nice day. Chris Angelico removing tongue from cheek -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Review
ad wrote: > Please review the code pasted below. I am wondering what other ways > there are of performing the same tasks. On a unix system, you would call "find" with according arguments and then handle the found files with "-exec rm ..." or something like that, but I see you are on MS Windows. > args = parser.parse_args() > > dictKeys = (vars(args)) The first of these looks okay, while I don't get the additional brackets in the second one. Another habit I observe here is the Hungarian notation of prefixing the type to the name and using camelCaps. PEP 8 (IIRC) has something to say on the preferred naming. I'm not 100% against encoding the type in the variable name in Python, since it lacks static type checking, I would have chosen "key_dict" here though, or, due to the small size of the overall program just "keys". > print (HowManyDays) This puzzled me at first, again the useless additional brackets I thought. However, in Python 3, "print" is a function, so that is correct. Still, it should be "print(foo)" not "print (foo)". > for files in DirListing: > > # Get the absolute path of the file name > abspath = (os.path.join(WhatDirectory, files)) "files" is just the name of a single file, right? In that case the name is a bit confusing. > # Get the date from seven days ago > WeekOldFileDate = CurrentTime - DaysToDelete You are repeating this calculation for every file in the loop. > if FileCreationTime < WeekOldFileDate: > #check if the object is a file > if os.path.isfile(abspath): os.remove(abspath) > # It is not a file it is a directory > elif os.path.isdir(abspath): shutil.rmtree(abspath) I'm not sure, but I believe you could use shutil.rmtree() for both files and directories. In any case, be prepared for the file still being open or otherwise read-only, i.e. for having to handle errors. Also, what if a directory is old but the content is new? Would this cause the non-old content to be deleted? Cheers! Uli -- Domino Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
pyGTK identify a button
Hi all, i'm trying to write a simple windows with two button in GTK, i need a way to identify wich button is pressed. Consider that: the two button are connected (when clicked) to infoButton(self, widget, data=None) infoButton() is something like this infoButton(self, widget, data=None): # discover wich button was pressed ... # say hello to the button if button1pressed: print "Hi, button1!" else: print "Hi, button2!" so, how can I know wich button was pressed without using data and without reading the label of the button (i could have buttons with the same label) If data is needed, can someone pls tell me how to set it properly in glade 3.8 thanks Nico -- http://mail.python.org/mailman/listinfo/python-list
Re: File access denied after subprocess completion on Windows platform
> There used to be a problem with subprocess fds being held by
> a traceback. IIRC, the problem could be triggered by having
> an except clause around a subprocess call within which something
> attempted to, eg,
> remove one of the affected files.
I have no subprocess call.. in this last issue. And I didn't triggered
one (disabled the Button that runs the subprocess).
try:
for line in t.splitlines():
[...]
ret = self.downloadFileToDisk(filename, do_rename)
if not ret:
print "DEBUG: Problema la download"
raise Exception()
(1) except Exception as inst:
print type(inst)
print inst.args
self.updateText.emit("EROARE: Eroare la descarcare")
self.updateStatusBar.emit("EROARE: Eroare la descaracare
fisiere")
return
Where downloadFileToDisk():
def downloadFileToDisk(self, filename, final_rename=True):
dfilename = os.path.join(saveBasePATH, filename)
sfilename = dfilename + ".part"
dfolder = os.path.dirname(sfilename)
if dfolder != "":
if not os.path.isdir(dfolder):
os.makedirs(dfolder)
try:
fp = open(sfilename, "wb")
except:
return False
curl = pycurl.Curl()
curl.setopt(pycurl.URL, baseUpdateURL + "/client/" + filename)
curl.setopt(pycurl.CONNECTTIMEOUT, 30)
curl.setopt(pycurl.NOPROGRESS, 0)
curl.setopt(pycurl.FOLLOWLOCATION, 1)
curl.setopt(pycurl.MAXREDIRS, 5)
curl.setopt(pycurl.PROGRESSFUNCTION, self.updateFileProgress)
curl.setopt(pycurl.WRITEDATA, fp)
curl.setopt(pycurl.BUFFERSIZE, 4194304)
curl.setopt(pycurl.NOSIGNAL, 1)
curl.perform()
retcode = curl.getinfo(pycurl.HTTP_CODE)
curl.close()
fp.close()
if retcode != 200:
(2) os.unlink(sfilename)
return False
self.msleep(10)
if final_rename:
os.rename(sfilename, dfilename)
return True
Without self.msleep(10), (1) catches WindowsError: file access ... blah
blah. Maybe at (2) can be an access violation, but it wasn't triggered
yet in tests. I will move the sleep after fp.close(). Yes, I know that
what it've done with raise Exception() is UGLY, since this program it's
more a quick hack solution to a problem :). Anyway the Exception that is
catched is not rised by my code (it's a WindowsError).
> I'm sorry if that's a bit
> of a woolly description but if you think this might be
> biting you I'll dive in and look at the code. What version
> of Python are you using?
Last 2.7.x. Well, if os.rename is instead a subprocess call, then it's
subprocess based. I'm new to Python but 99% I think it's a system call
:)
> (That said, the fact that the behaviour varies between faster
> and slower computers makes that cause unlikely. Maybe we're
> back to looking at virus checkers and the like...)
On that virtual machine there is no virus checker. On the faster machine
I disabled and closed the antivirus.
--
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GNU GPG Key: http://claudiu.targujiu.net/key.gpg
T: +40 755 135455
E: [email protected], [email protected]
signature.asc
Description: This is a digitally signed message part.
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Re: pyGTK identify a button
> the two button are connected (when clicked) to infoButton(self, > widget, > data=None) From documentation: handler_id = object.connect(name, func, func_data) So: button1.connect(when is pressed, your_function, 1) button2.connect(when is pressed, your_function, 2) (This code is conception, I don't really know how is done in GTK). On the callback: infoButton(self, widget, data=None): # discover wich button was pressed ... # say hello to the button if data == 1: print "Hi, button1!" else: print "Hi, button2!" -- Claudiu Nicolaie CISMARU GNU GPG Key: http://claudiu.targujiu.net/key.gpg T: +40 755 135455 E: [email protected], [email protected] signature.asc Description: This is a digitally signed message part. -- http://mail.python.org/mailman/listinfo/python-list
Re: Hotshoting recursive function
En Sun, 22 May 2011 10:42:08 -0300, Selvam escribió: I am using hotshot module to profile my python function. I used the details from ( http://code.activestate.com/recipes/576656-quick-python-profiling-with-hotshot/ ). The function I profile is a recursive one and I am getting the following error, "ProfilerError: profiler already active" I guess this is due to the recursive call to the profiling function. I would like to get some suggestions. The recursive call inside your function should call the undecorated function, not the decorated function again. Decorator syntax is not convenient anymore. Using the same names as in the recipe example: # a recursive function def my_slow_function(n): ... return my_slow_function(n-1) my_profiled_slow_function = hotshotit(my_slow_function) my_profiled_slow_function(n) This works, in the sense that it does not raise ProfileError anymore. Interpreting profile data is up to you... -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: Link errors embedding Python 3.2
Followup. I'm now using Python 3.3 straight from Mercurial, and am seeing the same issues. I've managed to get the compilation step to succeed by naming the library for full inclusion and adding -lutil -ldl (sounding rather Donizetti there), and my program runs. However, it's unable to import all its modules. I can happily import re, string, and sys, but importing math or time results in an ImportError citing "undefined symbol: PyExc_ValueError". I think there's still something I'm mucking up in the link process. The exception is ImportError, with text: '/usr/local/lib/python3.3/lib-dynload/time.cpython-33m.so: undefined symbol: PyExc_ValueError' Any ideas? Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: pyGTK identify a button
On 25/05/2011 10:44, Claudiu Nicolaie CISMARU wrote: the two button are connected (when clicked) to infoButton(self, widget, data=None) From documentation: handler_id = object.connect(name, func, func_data) So: button1.connect(when is pressed, your_function, 1) button2.connect(when is pressed, your_function, 2) (This code is conception, I don't really know how is done in GTK). thanks but, as i've sayed before, i can't use func_data 'cause i don't know how to set it on glade3.8, that is the program i use to create the GUI. Anyway, i think this is the only way to identify the button :-/ -- http://mail.python.org/mailman/listinfo/python-list
Re: pyGTK identify a button
On Wed, May 25, 2011 at 6:18 PM, Tracubik wrote: > Hi all, > i'm trying to write a simple windows with two button in GTK, i need a way to > identify wich button is pressed. > Consider that: > > the two button are connected (when clicked) to infoButton(self, widget, > data=None) I'm not terribly familiar with GTK, but I believe the 'widget' parameter is the button that was clicked on. Whatever means you have for distinguishing them (saving another reference to each object in a named variable, etc), you should be able to do with that parameter. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: pyGTK identify a button
> thanks but, as i've sayed before, i can't use func_data 'cause i don't > know how to set it on glade3.8, that is the program i use to create > the > GUI. > Anyway, i think this is the only way to identify the button :-/ Hack into the generated source! -- Claudiu Nicolaie CISMARU GNU GPG Key: http://claudiu.targujiu.net/key.gpg T: +40 755 135455 E: [email protected], [email protected] signature.asc Description: This is a digitally signed message part. -- http://mail.python.org/mailman/listinfo/python-list
Re: Beginner needs advice
Lew Schwartz wrote: So, if I read between the lines correctly, you recommend Python 3? Does the windows version install with a development environment? If you want to use python 3, make sure before that all the good stuff you need (==modules) have been ported to python 3. If you are a complete beginner, I would advise python 2.7. JM -- http://mail.python.org/mailman/listinfo/python-list
Re: pexpect: TIMEOUT no longer clears child.before
En Thu, 19 May 2011 08:29:21 -0300, Adrian Casey escribió: The behaviour of pexpect has changed between version 2.1 and 2.3. In version 2.1, the following code would result in child.before being cleared -: >>>child.expect(pexpect.TIMEOUT,1) In version 2.3, this is no longer the case. No matter how many times the above code is run, child.before continues to hold the output from previous commands. It is important to be able to clear the contents of child.before between each command. What is the correct way to do this in version 2.3? Try contacting the author: www.noah.org -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
[pyodbc] Setting values to SQL_* constants while creating a connection
Hi,
I would like to know how to set values to values to SQL_* constants while
creating a db connection through pyodbc module.
For example, i am getting a connection object like below:
In [27]: dbh1 = pyodbc.connect("DSN=;UID=
;PWD=;DATABASE=;APP=")
In [28]: dbh1.getinfo(pyodbc.SQL_DESCRIBE_PARAMETER)
Out[28]: True
I want to set this SQL_DESCRIBE_PARAMETER to false for this connection
object. How could i do that?
Please help me in figuring it out.
Thanks,
Srini
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Re: English Idiom in Unix: Directory Recursively
On Wed, 25 May 2011 08:14:27 +1000, Chris Angelico wrote: > On Wed, May 25, 2011 at 3:40 AM, Xah Lee wrote: >> On May 23, 9:28 pm, Chris Angelico wrote: >>> Because I do not consider its behaviour to be errant. And I suspect >>> its main developers won't either. That's why I suggested you grab the >>> sources and make The Perfect Emacs. >> >> why don't you try http://ergoemacs.org/ ? > > You miss my point. I am not desiring of a different emacs; you were the > one complaining about its shortcomings. It's Xah Lee. Of course he misses your point. He refuses to stop spamming newsgroups even after being banned by his ISP, and he refuses to listen to any opinion that doesn't agree with his own. Everyone else is an idiot. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Obtaining a full path name from file
On 01/-10/-28163 02:59 PM, RVince wrote: s = "C:\AciiCsv\Gravity_Test_data\A.csv" f = open(s,"r") How do I obtain the full pathname given the File, f? (which should equal "C:\AciiCsv\Gravity_Test_data"). I've tried all sorts of stuff and am just not finding it. Any help greatly appreciated ! I saw lots of responses, but I don't think anybody pointed out that the filename is probably invalid. This particular string will work, but if you have a directory that starts with a T or an N, you may get some surprises. The backslash is treated specially in a literal string. When building a Windows directory name in a literal string, you generally need to do one of three things: 1) use raw literals 2) double the backslash 3) use a forward slash DaveA -- http://mail.python.org/mailman/listinfo/python-list
ANN: eGenix mxODBC - Python ODBC Database Interface 3.1.1
ANNOUNCING eGenix.com mxODBC - Python ODBC Database Interface Version 3.1.1 mxODBC is our commercially supported Python extension providing ODBC database connectivity to Python applications on Windows, Mac OS X, Unix and BSD platforms This announcement is also available on our web-site for online reading: http://www.egenix.com/company/news/eGenix-mxODBC-3.1.1-GA.html INTRODUCTION mxODBC provides an easy-to-use, high-performance, reliable and robust Python interface to ODBC compatible databases such as MS SQL Server, MS Access, Oracle Database, IBM DB2 and Informix , Sybase ASE and Sybase Anywhere, MySQL, PostgreSQL, SAP MaxDB and many more: http://www.egenix.com/products/python/mxODBC/ The "eGenix mxODBC - Python ODBC Database Interface" product is a commercial extension to our open-source eGenix mx Base Distribution: http://www.egenix.com/products/python/mxBase/ NEWS mxODBC 3.1 Update - The mxODBC 3.1.1 patch level release adds compatibility to our new eGenix.com mx Base Distribution 3.2.0, which includes Windows x64 support. If you are currently using the combinations mxODBC 3.1.0 + mx Base 3.1.3, please consider upgrading to our latest releases mxODBC 3.1.1 + mx Base 3.2.0. Licenses for mxODBC 3.1.0 remain valid for mxODBC 3.1.1 as well. Release Highlights -- * We've added Python 2.7 support and builds for all platforms. * mxODBC 3.1 adds native support for the Windows 64-bit platforms as well as the Mac OS X 10.6 (Snow Leopard) 64-bit builds of Python. * mxODBC now fully supports the Oracle Instant Client ODBC driver. * We have updated the support for the latest IBM DB2 9.7 ODBC drivers and enhanced compatibility of mxODBC with the MS SQL Server Native Client ODBC driver on Windows and the Sybase ASE 15 ODBC drivers on Unix. * mxODBC 3.1 adds support for large-scale data warehouse databases Netezza and Teradata. * In addition to the Windows, Mac OS X, iODBC and unixODBC ODBC driver managers, we now also include support for the DataDirect ODBC manager. * The 64-bit support on Unix platforms was updated to support the new unixODBC 2.3.0 version. * We've improved the documentation on how to connect to various popular databases and now include many tips & tricks for each database/driver. * The Python 2.7 memoryview object is now supported as binary data container. * We have simplified handling of database warnings using a new customizable .warningformat attribute. * The catalog methods now accept both Unicode and 8-bit strings as parameters. * You can now select whether to use ANSI (8-bit) or Unicode ODBC APIs in the ODBC drivers, removing unnecessary data conversions and enhancing ODBC driver compatibility. For the full set of changes please check the mxODBC change log: http://www.egenix.com/products/python/mxODBC/changelog.html Feature Highlights -- * Python Database API 2.0 Compliance: the mxODBC API is fully Python DB-API 2.0 compatible and implements a large number of powerful extensions. * Support for all popular ODBC Drivers: mxODBC includes adjustments and work-arounds to support MS SQL Server Native Client, MS SQL Server ODBC Driver, FreeTDS ODBC Driver, Oracle Instant Client ODBC Driver, IBM DB2 ODBC Driver, Sybase ASE ODBC Driver, Netezza ODBC Driver, Teradata ODBC Driver, PostgreSQL ODBC Driver, MySQL ODBC Driver, .MaxDB ODBC Driver as well as the ODBC driver sets of EasySoft, DataDirect, OpenLink, Actual Technologies. * Support for all popular ODBC Driver Managers: mxODBC comes with subpackages for the native Windows and Mac OS X ODBC managers, as well as the ODBC managers unixODBC, iODBC and DataDirect, which are commonly used on Unix systems. * Stable, robust and reliable:the mxODBC API has been in active production use for more than 10 years. * Full Python Support: mxODBC works with Python 2.4, 2.5, 2.6 and 2.7. * Full 64-bit Support: mxODBC runs on the following 64-bit platforms: Windows, Linux, FreeBSD and Mac OS X. For the full set of features mxODBC has to offer, please see: http://www.egenix.com/products/python/mxODBC/#Features New mxODBC Editions --- Due to popular demand, we have extended the set of available mxODBC editions and included a new low-cost standard edition. mxODBC is now available in thesethree editions: * The low-cost Standard Edition which provides data connectivity to a selected set of databas
Re: Why did Quora choose Python for its development?
In article , Dennis Lee Bieber wrote: > On Tue, 24 May 2011 13:39:02 -0400, "D'Arcy J.M. Cain" > declaimed the following in gmane.comp.python.general: > > > > My point was that even proponents of the language can make a > > significant error based on the way the variable is named. It's like > > the old Fortran IV that I first learned where the name of the variable > > determined whether it was an integer or a floating point. > > > Only if one didn't declare the type ahead of time... > > And even then it wasn't that hard to remember (using a non-PC > mnemonic): Indian's are integer (variables starting I to N inclusive > were integers) Remembering that I, J, K, L, M, and N were integer was trivial if you came from a math background. And, of course, Fortran was all about math, so that was natural. Those letters are commonly used for integers in formulae. If I write $ x sub i $, anybody who knows math would immediately assume that the range of x was reals and the range of i was integers. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, May 25, 2011 at 9:36 PM, Roy Smith wrote: > Remembering that I, J, K, L, M, and N were integer was trivial if you > came from a math background. And, of course, Fortran was all about > math, so that was natural. Those letters are commonly used for integers > in formulae. If I write $ x sub i $, anybody who knows math would > immediately assume that the range of x was reals and the range of i was > integers. When I studied maths, x and y were reals, and i wasn't. But it wasn't integer either... :) Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
Dennis Lee Bieber writes: > Python books than after six months of trying to understand PERL... And Perl is the language, and perl is what runs Perl. -- John Bokma j3b Blog: http://johnbokma.com/Perl Consultancy: http://castleamber.com/ Perl for books:http://johnbokma.com/perl/help-in-exchange-for-books.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
Thorsten Kampe writes: > * Chris Angelico (Wed, 25 May 2011 08:01:38 +1000) >> >> On Wed, May 25, 2011 at 3:39 AM, D'Arcy J.M. Cain wrote: >> > One of my favorite quotes (not sure if it was about Perl or APL) is > "I >> > refuse to use a programming language where the proponents of it stick >> > snippets under each other's nose and say 'I bet you can't guess what >> > this does.'" >> >> Yes, I believe that was Perl. And an amusing quote. But most of the >> point of it comes from the fact that Perl uses punctuation for most of >> its keywords, whereas (say) Python uses English words; it's a lot more >> fun to crunch something down when you can use $| and friends than when >> you have to put "x and y", complete with spaces, for a simple boolean. >> But that says nothing about which language is actually better for >> working with... [...] > > It does say something about readibility. And yes, "readability counts". > And yes, readability says a lot about how good a language is for reading > and working with. To people used to the latin alphabet languages using a different script are unreadable. So readability has a lot to do with what one is used to. Like I already stated before: if Python is really so much better than Python readability wise, why do I have such a hard time dropping Perl and moving on? -- John Bokma j3b Blog: http://johnbokma.com/Perl Consultancy: http://castleamber.com/ Perl for books:http://johnbokma.com/perl/help-in-exchange-for-books.html -- http://mail.python.org/mailman/listinfo/python-list
Unable to make ironpython run in browser with silverlight
Basically i am following this tutorial:
http://blog.jimmy.schementi.com/2010/03/pycon-2010-python-in-browser.html
According to it, this code should run fine:
http://www.w3.org/TR/html4/strict.dtd";>
http://gestalt.ironpython.net/dlr-20100305.js";>
http://github.com/jschementi/
pycon2010/raw/master/repl.py">
window.Alert("Hello from Python!")
And in fact, it does, for example here:
http://ironpython.net/browser/examples/pycon2010/start.html
You will see it if you have silverlight installed.
But the problem is that when I try to make the same code run on my PC,
I can't do it. I create a text file, copy this code there, save it as
test.html, and run with firefox, but nothing happens. Code does not
execute, i just get a blank page. I can't understand the reason why
the same code runs here:
http://ironpython.net/browser/examples/pycon2010/start.html,
but not on my PC, given that it is a client side code, and not the
server side.
And there is nothing written in firefox error console, when I run it
locally.
But if I host it on my webhosting account, then I get this error:
Error: uncaught exception: [Exception... "Component returned failure
code: 0x80004005 (NS_ERROR_FAILURE) [nsIXMLHttpRequest.send]"
nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: http://
sitename .com/silverlighttest.html :: DLR_DownloadResource :: line 15"
data: no]
I uploaded the html file I am using here:
http://www.filedropper.com/silverlighttest
But it just a text file with that code with extension changed
to .html.
What can I do?
--
http://mail.python.org/mailman/listinfo/python-list
mresh
website --> www.srilakshmi.infoinyohyou -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
In article , Chris Angelico wrote: > On Wed, May 25, 2011 at 9:36 PM, Roy Smith wrote: > > Remembering that I, J, K, L, M, and N were integer was trivial if you > > came from a math background. And, of course, Fortran was all about > > math, so that was natural. Those letters are commonly used for integers > > in formulae. If I write $ x sub i $, anybody who knows math would > > immediately assume that the range of x was reals and the range of i was > > integers. > > When I studied maths, x and y were reals, and i wasn't. But it wasn't > integer either... :) I was talking of i in the context of a variable, not as a constant. If I write $ 3 + 7i $ in one place and $ x sub i $ in another, most people will figure out from the context which is which. -- http://mail.python.org/mailman/listinfo/python-list
Re: Beginner needs advice
On 25-May-11 02:22 AM, Lew Schwartz wrote: So, if I read between the lines correctly, you recommend Python 3? Does the windows version install with a development environment? It would be safer to stick with Python 2.7 initially and then consider the transition to 3.2 later. No, there is not more than Idle. PyScripter provides an excellent development environment. See: http://en.wikipedia.org/wiki/PyScripter Colin W. -- http://mail.python.org/mailman/listinfo/python-list
Newbie string questions
Hey everyone, This is a super noob question, so please be gentle. I am working my way through "Learn Python the Hard Way" using both python 2.7 and python 3.1 (I want to get a handle on the differences between the two - the intention to write things in python 3 but be able to understand things from python 2). The first quarter or so of the book details lots of stuff about strings. Most of the learning is by doing, with less of an emphasis on the theory behind what certain things actually do. The issue is, I can't seem to find some of the items in the documentation. Right now what is stumping me... what exactly does %r do? I can't find it in the documentation anywhere. -Matty -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie string questions
On Wed, May 25, 2011 at 11:06 PM, Matty Sarro wrote: > Right now what is stumping me... what exactly does %r do? You're talking about the formatting operator? It's like the repr function: http://docs.python.org/library/functions.html#repr Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie string questions
On Wednesday, May 25, 2011 9:06:02 AM UTC-4, Matty Sarro wrote: > can't seem to find some of the items in the documentation. Right now > what is stumping me... what exactly does %r do? I can't find it in the > documentation anywhere. Matty, %r in a format string is very much like %s. %s calls str(your_object) in order to produce the resulting string. %r calls repr(your_object). Generally, you'd want to use %s for strings that will surface to a user, while %r is great for debugging and logging. Also, if you haven't come across repr(), you should be able to find that in the docs; it's also considered good practice to overload repr() in your own classes in order to provide a useful representation for your objects. -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie string questions
Thanks guys! I appreciate it. I was wondering why %r was always showing things enclosed in single-quotes. On Wed, May 25, 2011 at 9:13 AM, Chris Guidry wrote: > On Wednesday, May 25, 2011 9:06:02 AM UTC-4, Matty Sarro wrote: >> can't seem to find some of the items in the documentation. Right now >> what is stumping me... what exactly does %r do? I can't find it in the >> documentation anywhere. > > Matty, %r in a format string is very much like %s. %s calls str(your_object) > in order to produce the resulting string. %r calls repr(your_object). > Generally, you'd want to use %s for strings that will surface to a user, > while %r is great for debugging and logging. > > Also, if you haven't come across repr(), you should be able to find that in > the docs; it's also considered good practice to overload repr() in your own > classes in order to provide a useful representation for your objects. > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
FW: python
python We should take a look at how this latest good fortune is going to change your lifestyle. Don't you remember all of those times I said how hard it's been just to get by? Alright you know what?, Your computer is going to be your very best pal once you try out this thing for one month's time. There's really no way in hell I'd wind up where I am these days if it all wasn't for this. You can give thanks to me soon. The couple of people I sometimes will need to deal with help to make everything far more easy on me that I couldn't have this another way. I can't wait to meet you once again and show you lots more. If you fail to build an income with this method, you're probably stupid. I'm sorry if that offends you, but I recognize you're capable and this is extremely straight forward! http://jesus21news.com Right here is the chance of your life. When you're ready to transform your way of life around, I'm going to be right here to assist. So whaddaya think, python, think you're prepared for a change? -- http://mail.python.org/mailman/listinfo/python-list
Re: Unable to make ironpython run in browser with silverlight
Here is how it looks on free webhosting account: http://silverlighttest.zzl.org/silverlighttest.html It is supposed to show a window with "Hello from python", but it shows smth else completely. -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Review
On May 25, 4:06 am, Ulrich Eckhardt wrote: > ad wrote: > > Please review the code pasted below. I am wondering what other ways > > there are of performing the same tasks. > > On a unix system, you would call "find" with according arguments and then > handle the found files with "-exec rm ..." or something like that, but I see > you are on MS Windows. > > > args = parser.parse_args() > > > dictKeys = (vars(args)) > > The first of these looks okay, while I don't get the additional brackets in > the second one. Another habit I observe here is the Hungarian notation of > prefixing the type to the name and using camelCaps. PEP 8 (IIRC) has > something to say on the preferred naming. I'm not 100% against encoding the > type in the variable name in Python, since it lacks static type checking, I > would have chosen "key_dict" here though, or, due to the small size of the > overall program just "keys". > > > print (HowManyDays) > > This puzzled me at first, again the useless additional brackets I thought. > However, in Python 3, "print" is a function, so that is correct. Still, it > should be "print(foo)" not "print (foo)". > > > for files in DirListing: > > > # Get the absolute path of the file name > > abspath = (os.path.join(WhatDirectory, files)) > > "files" is just the name of a single file, right? In that case the name is a > bit confusing. > > > # Get the date from seven days ago > > WeekOldFileDate = CurrentTime - DaysToDelete > > You are repeating this calculation for every file in the loop. > > > if FileCreationTime < WeekOldFileDate: > > #check if the object is a file > > if os.path.isfile(abspath): os.remove(abspath) > > # It is not a file it is a directory > > elif os.path.isdir(abspath): shutil.rmtree(abspath) > > I'm not sure, but I believe you could use shutil.rmtree() for both files and > directories. In any case, be prepared for the file still being open or > otherwise read-only, i.e. for having to handle errors. > > Also, what if a directory is old but the content is new? Would this cause > the non-old content to be deleted? > > Cheers! > > Uli > > -- > Domino Laser GmbH > Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 Thank you guys very much for the excellent points. I will use this information as a reference as I write more code and fix up the existing script. Chris, thank you for putting so much time into your post! Until we type again... -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, 25 May 2011 07:36:40 -0400 Roy Smith wrote: > Remembering that I, J, K, L, M, and N were integer was trivial if you > came from a math background. And, of course, Fortran was all about The easiest way to remember was that the first two letters of INteger gave you the range. -- D'Arcy J.M. Cain | 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: Why did Quora choose Python for its development?
On Thu, May 26, 2011 at 12:23 AM, D'Arcy J.M. Cain wrote: > The easiest way to remember was that the first two letters of INteger > gave you the range. > G for Green and R for Right, which are the first two letters of Green. (I wonder how many Pythonistas are familiar with that?) Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Review
On May 25, 2:44 pm, ad wrote: > On May 25, 4:06 am, Ulrich Eckhardt > wrote: > > > > > ad wrote: > > > Please review the code pasted below. I am wondering what other ways > > > there are of performing the same tasks. > > > On a unix system, you would call "find" with according arguments and then > > handle the found files with "-exec rm ..." or something like that, but I see > > you are on MS Windows. > > > > args = parser.parse_args() > > > > dictKeys = (vars(args)) > > > The first of these looks okay, while I don't get the additional brackets in > > the second one. Another habit I observe here is the Hungarian notation of > > prefixing the type to the name and using camelCaps. PEP 8 (IIRC) has > > something to say on the preferred naming. I'm not 100% against encoding the > > type in the variable name in Python, since it lacks static type checking, I > > would have chosen "key_dict" here though, or, due to the small size of the > > overall program just "keys". > > > > print (HowManyDays) > > > This puzzled me at first, again the useless additional brackets I thought. > > However, in Python 3, "print" is a function, so that is correct. Still, it > > should be "print(foo)" not "print (foo)". > > > > for files in DirListing: > > > > # Get the absolute path of the file name > > > abspath = (os.path.join(WhatDirectory, files)) > > > "files" is just the name of a single file, right? In that case the name is a > > bit confusing. > > > > # Get the date from seven days ago > > > WeekOldFileDate = CurrentTime - DaysToDelete > > > You are repeating this calculation for every file in the loop. > > > > if FileCreationTime < WeekOldFileDate: > > > #check if the object is a file > > > if os.path.isfile(abspath): os.remove(abspath) > > > # It is not a file it is a directory > > > elif os.path.isdir(abspath): shutil.rmtree(abspath) > > > I'm not sure, but I believe you could use shutil.rmtree() for both files and > > directories. In any case, be prepared for the file still being open or > > otherwise read-only, i.e. for having to handle errors. > > > Also, what if a directory is old but the content is new? Would this cause > > the non-old content to be deleted? > > > Cheers! > > > Uli > > > -- > > Domino Laser GmbH > > Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 > > Thank you guys very much for the excellent points. I will use this > information as a reference as I write more code and fix up the > existing script. > > Chris, thank you for putting so much time into your post! > > Until we type again... Wrote something to do the same basic thing a little while ago. Less verbose than yours, and it only does files, not folders. If I was going to do folders though, I'd do them by recursing into them and pruning files, and not go by the folder modify date, which I don't think changes the way you think it changes (for example, if a file inside a folder got updated such that it shouln't be deleted it still will be with your code if the folder modify date is old [this is on Windows]) import os, glob, time, sys if len(sys.argv) < 3: print "USAGE: %s " % sys.argv[0] sys.exit(1) pattern = sys.argv[1] days = int(sys.argv[2]) threshold = days * 24 * 60 * 60 t = time.time() for f in glob.glob(pattern): if t - os.stat(f)[9] > threshold: print f os.remove(f) -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, 25 May 2011 10:23:59 -0400, D'Arcy J.M. Cain wrote: > On Wed, 25 May 2011 07:36:40 -0400 > Roy Smith wrote: >> Remembering that I, J, K, L, M, and N were integer was trivial if you >> came from a math background. And, of course, Fortran was all about > > The easiest way to remember was that the first two letters of INteger > gave you the range. Huh. I never knew that. I just learned from use that I, J, K, M and N were traditionally integers. I never used L for an integer variable, and don't know anyone who does. I for integer is obvious. If you need a second one, you use the next letter J, and if you need a third, the one after that, K. If you need four, you're probably doing something wrong. Likewise, N for number (as in, *counting* number). If you need two, using N and O is stupid, because O can be confused with 0, so you go backwards and use M. However, using P and Q for integers is merely arbitrary convention. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Kind of OT - Books on software development?
Hey everyone, I am looking at some projects coming up, which may or may not involve python. So I figured I would throw the question out there and see what everyone thinks. I am looking for some books on software engineering/development... something that discusses techniques from ideation, up through testing, QA, production, and then maintenance. Is there such a book? -Matthew -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
I hate using L for anything, namely because if you type it lowercase you always have to wonder if its an l or a 1 in a terminal window. -Matthew On Wed, May 25, 2011 at 10:56 AM, Steven D'Aprano wrote: > On Wed, 25 May 2011 10:23:59 -0400, D'Arcy J.M. Cain wrote: > >> On Wed, 25 May 2011 07:36:40 -0400 >> Roy Smith wrote: >>> Remembering that I, J, K, L, M, and N were integer was trivial if you >>> came from a math background. And, of course, Fortran was all about >> >> The easiest way to remember was that the first two letters of INteger >> gave you the range. > > Huh. I never knew that. I just learned from use that I, J, K, M and N > were traditionally integers. I never used L for an integer variable, and > don't know anyone who does. > > I for integer is obvious. If you need a second one, you use the next > letter J, and if you need a third, the one after that, K. If you need > four, you're probably doing something wrong. > > Likewise, N for number (as in, *counting* number). If you need two, using > N and O is stupid, because O can be confused with 0, so you go backwards > and use M. > > However, using P and Q for integers is merely arbitrary convention. > > > > -- > Steven > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: Kind of OT - Books on software development?
I do not have my library with me, but I remember a book that fits the bill exactly, is was from Microsoft Press, I think it was called "Writing Solid Code" Hope this helps, -EdK Ed Keith [email protected] Blog: edkeith.blogspot.com --- On Wed, 5/25/11, Matty Sarro wrote: > From: Matty Sarro > Subject: Kind of OT - Books on software development? > To: "Python list" > Date: Wednesday, May 25, 2011, 11:40 AM > Hey everyone, > I am looking at some projects coming up, which may or may > not involve > python. So I figured I would throw the question out there > and see what > everyone thinks. > I am looking for some books on software > engineering/development... > something that discusses techniques from ideation, up > through testing, > QA, production, and then maintenance. Is there such a > book? > -Matthew > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: Kind of OT - Books on software development?
On May 25, 11:45 am, Ed Keith wrote: > I do not have my library with me, but I remember a book that fits the bill > exactly, is was from Microsoft Press, I think it was called "Writing Solid > Code" > > Hope this helps, > > -EdK > > Ed Keith > [email protected] > > Blog: edkeith.blogspot.com > > --- On Wed, 5/25/11, Matty Sarro wrote: > > > > > From: Matty Sarro > > Subject: Kind of OT - Books on software development? > > To: "Python list" > > Date: Wednesday, May 25, 2011, 11:40 AM > > Hey everyone, > > I am looking at some projects coming up, which may or may > > not involve > > python. So I figured I would throw the question out there > > and see what > > everyone thinks. > > I am looking for some books on software > > engineering/development... > > something that discusses techniques from ideation, up > > through testing, > > QA, production, and then maintenance. Is there such a > > book? > > -Matthew > > -- > >http://mail.python.org/mailman/listinfo/python-list- Hide quoted text - > > - Show quoted text - If you are talking about general concepts in efficient, effective OO programming I'd suggest "Smalltalk Best Practice Patterns" by Kent Beck. I've developed in Java, C#, Python, Ruby, Smalltalk, and other languages and this book is an eye opener! -- http://mail.python.org/mailman/listinfo/python-list
Re: Kind of OT - Books on software development?
Hey everyone, I am looking at some projects coming up, which may or may not involve python. So I figured I would throw the question out there and see what everyone thinks. I am looking for some books on software engineering/development... something that discusses techniques from ideation, up through testing, QA, production, and then maintenance. Is there such a book? -Matthew On Wed, May 25, 2011 at 11:45 AM, Ed Keith wrote: > I do not have my library with me, but I remember a book that fits the bill > exactly, is was from Microsoft Press, I think it was called "Writing Solid > Code" > Matt - Roger Pressman - Software Engineering, A Practicioner's Approach is a good one. Donald E. Knuth. - The Art of Computer Programming (5 Volumes) - http://www-cs-faculty.stanford.edu/~uno/taocp.html Horowitz - Fundamentals of Computer Algorithms Dowd, Macdonald, Shuh - The Art of Software Security Assessments Good Basic Reference Library for engineering, designing, writing, and SECURING code. I've got lots more titles on various aspects of engineering and OOA/OOD construction, design methods, etc., but these are (imo) a good foundation. Regards Jack -- http://mail.python.org/mailman/listinfo/python-list
Re: pyGTK identify a button
Tracubik wrote:
> Hi all,
> i'm trying to write a simple windows with two button in GTK,
> i need a way to identify wich button is pressed.
>
#!/usr/bin/env python
import gtk
def console_display( button , args ) :
a0 , a1 , a2 = args
print '%s %s %s ' % ( a0 , a1 , a2 )
window = gtk.Window()
window.set_title( "gtk.buttons.01" )
window.set_size_request( 300 , -1 )
window.set_position( gtk.WIN_POS_CENTER )
window.connect( "destroy" , gtk.main_quit )
# Create VBox and add in Window
vbox = gtk.VBox()
window.add( vbox )
# Create buttons
dict_buttons = {
12 : [ 'OneTwo' , 'Buckle ' , 'My Shoe' ] ,
34 : [ 'TreFor' , 'Shut ' , 'The Door' ] ,
56 : [ 'FivSix' , 'Pick ' , 'Up Sticks' ] ,
78 : [ 'SvnAte' , 'Lay' , 'Them Straight' ] ,
910 : [ 'NinTen' , 'Big' , 'Fat Hen' ] }
list_keys = dict_buttons.keys()
list_keys.sort()
for this_button in list_keys :
this_name = dict_buttons[ this_button ][ 0 ]
b = gtk.Button( this_name )
b.set_name( this_name )
b.connect( "clicked" , console_display , dict_buttons[ this_button ] )
vbox.pack_start( b )
window.show_all()
gtk.main()
--
Stanley C. Kitching
Human Being
Phoenix, Arizona
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On 5/25/2011 8:01 AM, John Bokma wrote: to. Like I already stated before: if Python is really so much better than Python readability wise, why do I have such a hard time dropping Perl and moving on? [you meant 'than Perl'] You are one of the people whose brain fits Perl (or vice versa) better than most. So enjoy it. Ignore anyone who says otherwise. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
Terry Reedy wrote: On 5/25/2011 8:01 AM, John Bokma wrote: to. Like I already stated before: if Python is really so much better than Python readability wise, why do I have such a hard time dropping Perl and moving on? [you meant 'than Perl'] You are one of the people whose brain fits Perl (or vice versa) better than most. So enjoy it. Ignore anyone who says otherwise. +1 If everybody's brain worked the same, we wouldn't have so many different languages to choose from. ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: Kind of OT - Books on software development?
--- On Wed, 5/25/11, Ed Keith wrote: > I do not have my library with me, but > I remember a book that fits the bill exactly, is was from > Microsoft Press, I think it was called "Writing Solid Code" I have done some research at amazon.com, and while "Writing Solid Code" is an excellent book that I would also recommend highly, the book I was thinking of was "Code Complete". -EdK Ed Keith [email protected] Blog: edkeith.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
super() in class defs?
I may be attempting something improper here, but maybe I'm just going about it the wrong way. I'm subclassing http.server.CGIHTTPRequestHandler, and I'm using a decorator to add functionality to several overridden methods. def do_decorate(func): . def wrapper(self): . if appropriate(): . return func() . complain_about_error() . return wrapper class myHandler(CGIHTTPRequestHandler): . @do_decorate . def do_GET(self): . return super().do_GET() . # also override do_HEAD and do_POST My first thought was that I could just replace that whole method definition with one line: class myHandler(CGIHTTPRequestHandler): . do_GET = do_decorate(super().do_GET) That generates the following error: SystemError: super(): __class__ cell not found So I guess that when super() is called in the context of a class def rather than that of a method def, it doesn't have the information it needs. Now I'll probably just say: do_GET = do_decorate(CGIHTTPRequestHandler.do_GET) but I wonder if there is a "correct" way to do this instead? Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Cherrypy
Is anyone having a step by step tutorial of cherrypy(or book title).I have used the tutorial in their site as well as the book (cherrypy essentials) and I would like to have a one that is a bit more step by step...Please help... -- Regards, Bryton. -- http://mail.python.org/mailman/listinfo/python-list
Newbie question about SQLite + Python and twitter
Helo guys, I'm building a local application for twitter for my brother's store. I'm in the beginning and I have some newbie problems, so: I create a table called tb_messages with int auto increment and varchar(140) fields; I did three SQL funcionts, insert_tweet, delete_tweet, select_tweet select_tweet is use for getting messages for sending them to twitter; My problem is: How can i make my select_tweet works at the same time that insert or delete funcions. I just got to work when I stop select function. I would like to do my app works all the time. --- Jayme Proni Filho Skype: jaymeproni Twitter: @jaymeproni Phone: +55 - 17 - 3631 - 6576 Mobile: +55 - 17 - 9605 - 3560 e-Mail: jaymeproni at yahoo dot com dot br --- -- http://mail.python.org/mailman/listinfo/python-list
Re: super() in class defs?
On Wed, May 25, 2011 at 11:54 AM, Jess Austin wrote: > So I guess that when super() is called in the context of a class def > rather than that of a method def, it doesn't have the information it > needs. Now I'll probably just say: > > do_GET = do_decorate(CGIHTTPRequestHandler.do_GET) > > but I wonder if there is a "correct" way to do this instead? Thanks! I would recommend against using super() in general. http://fuhm.net/super-harmful/ Cheers, Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
Ethan Furman writes: > Terry Reedy wrote: >> On 5/25/2011 8:01 AM, John Bokma wrote: >> >>> to. Like I already stated before: if Python is really so much better >>> than Python readability wise, why do I have such a hard time dropping >>> Perl and moving on? >> >> [you meant 'than Perl'] You are one of the people whose brain fits >> Perl (or vice versa) better than most. So enjoy it. Ignore anyone >> who says otherwise. > > +1 > > If everybody's brain worked the same, we wouldn't have so many > different languages to choose from. So, this means that in general language readability is not as clear cut as some seem to advertise ;-). -- John Bokma j3b Blog: http://johnbokma.com/Perl Consultancy: http://castleamber.com/ Perl for books:http://johnbokma.com/perl/help-in-exchange-for-books.html -- http://mail.python.org/mailman/listinfo/python-list
Python 3.2 bug? Reading the last line of a file
The following function that returns the last line of a file works perfectly well under Python 2.71. but fails reliably under Python 3.2. Is this a bug, or am I doing something wrong? Any help would be greatly appreciated. import os def lastLine(filename): ''' Returns the last line of a file file.seek takes an optional 'whence' argument which allows you to start looking at the end, so you can just work back from there till you hit the first newline that has anything after it Works perfectly under Python 2.7, but not under 3.2! ''' offset = -50 with open(filename) as f: while offset > -1024: offset *= 2 f.seek(offset, os.SEEK_END) lines = f.readlines() if len(lines) > 1: return lines[-1] If I execute this with a valid filename fn. I get the following error message: >>> lastLine(fn) Traceback (most recent call last): File "", line 1, in lastLine(fn) File "", line 13, in lastLine f.seek(offset, os.SEEK_END) io.UnsupportedOperation: can't do nonzero end-relative seeks Sincerely Thomas Philips -- http://mail.python.org/mailman/listinfo/python-list
bdist_wininst: install_script not run on uninstall
Hi, according to the docs the installer bdist_wininst creates will run the install-script on install with -install (which works perfectly) and on uninstall with the -remove argument (which seemingly never happens). However I want to cleanup some registry stuff on uninstall so I want the uninstall script to work. Studying the source code of the installer[1] in the Run_RemoveScript function... [1] http://svn.python.org/view/python/trunk/PC/bdist_wininst/install.c ... it checks for the line '%d Run Script: %s' in the log, which is there. But can anybody find out why the install script is not run? with best regards, Wilbert Berendsen -- http://www.wilbertberendsen.nl/ "You must be the change you wish to see in the world." -- Mahatma Gandhi -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
On 25/05/2011 20:33, [email protected] wrote: The following function that returns the last line of a file works perfectly well under Python 2.71. but fails reliably under Python 3.2. Is this a bug, or am I doing something wrong? Any help would be greatly appreciated. import os def lastLine(filename): ''' Returns the last line of a file file.seek takes an optional 'whence' argument which allows you to start looking at the end, so you can just work back from there till you hit the first newline that has anything after it Works perfectly under Python 2.7, but not under 3.2! ''' offset = -50 with open(filename) as f: while offset> -1024: offset *= 2 f.seek(offset, os.SEEK_END) lines = f.readlines() if len(lines)> 1: return lines[-1] If I execute this with a valid filename fn. I get the following error message: lastLine(fn) Traceback (most recent call last): File "", line 1, in lastLine(fn) File "", line 13, in lastLine f.seek(offset, os.SEEK_END) io.UnsupportedOperation: can't do nonzero end-relative seeks You're opening the file in text mode, and seeking relative to the end of the file is not allowed in text mode, presumably because the file contents have to be decoded, and, in general, seeking to an arbitrary position within a sequence of encoded bytes can have undefined results when you attempt to decode to Unicode starting from that position. The strange thing is that you _are_ allowed to seek relative to the start of the file. Try opening the file in binary mode and do the decoding yourself, catching the DecodeError exceptions if/when they occur. -- http://mail.python.org/mailman/listinfo/python-list
Re: super() in class defs?
On Wed, May 25, 2011 at 12:31 PM, Ian Kelly wrote: > On Wed, May 25, 2011 at 11:54 AM, Jess Austin > wrote: > > So I guess that when super() is called in the context of a class def > > rather than that of a method def, it doesn't have the information it > > needs. Now I'll probably just say: > > > >do_GET = do_decorate(CGIHTTPRequestHandler.do_GET) > > > > but I wonder if there is a "correct" way to do this instead? Thanks! > > I would recommend against using super() in general. > > That position is understandable. However, super is fine for single inheritance, and works fine in cooperative multiple inheritance. You can just as easily argue that multiple inheritance is more harmful than super is. If fact, I would generally recommend against using multiple inheritance if you can avoid it (though it has its place). Personally, I find super to make maintenance and refactoring easier, since I don't have to fiddle with the base class name, or with passing self. Cheers, -eric > http://fuhm.net/super-harmful/ > > Cheers, > Ian > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
On Wed, May 25, 2011 at 2:00 PM, MRAB wrote: > You're opening the file in text mode, and seeking relative to the end > of the file is not allowed in text mode, presumably because the file > contents have to be decoded, and, in general, seeking to an arbitrary > position within a sequence of encoded bytes can have undefined results > when you attempt to decode to Unicode starting from that position. > > The strange thing is that you _are_ allowed to seek relative to the > start of the file. I think that with text files seek() is only really meant to be called with values returned from tell(), which may include the decoder state in its return value. -- http://mail.python.org/mailman/listinfo/python-list
using masks and numpy record arrays
Hello,
I am trying to work with a structured array and a mask, and am
encountering some problems.
For example:
>>> xtype = numpy.dtype([("n", numpy.int32), ("x", numpy.float32)])
>>> a = numpy.zeros((4), dtype=xtype)
>>> b = numpy.arange(0,4)
>>> a2 = numpy.zeros((4), dtype=xtype)
>>> mask = numpy.where(b%2 == 0)
>>> a2[:]["n"] += b! this changes the values of a2
>>> a[mask]["n"] += b[mask]! this does not change the values of a
>>> a2
array([(0, 0.0), (1, 0.0), (2, 0.0), (3, 0.0)],
dtype=[('n', '>> a
array([(0, 0.0), (0, 0.0), (0, 0.0), (0, 0.0)],
dtype=[('n', '>> a = numpy.zeros((4))
>>> a[mask] += b[mask]
>>> a
array([ 0., 0., 2., 0.])
What is it about a numpy record array that prevents the mask statement
from working, and how do I get around this?
Thanks,
Catherine
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, May 25, 2011 at 3:14 PM, John Bokma wrote: > Ethan Furman writes: > >> Terry Reedy wrote: >>> On 5/25/2011 8:01 AM, John Bokma wrote: >>> to. Like I already stated before: if Python is really so much better than Python readability wise, why do I have such a hard time dropping Perl and moving on? >>> >>> [you meant 'than Perl'] You are one of the people whose brain fits >>> Perl (or vice versa) better than most. So enjoy it. Ignore anyone >>> who says otherwise. >> >> +1 >> >> If everybody's brain worked the same, we wouldn't have so many >> different languages to choose from. > > So, this means that in general language readability is not as clear cut > as some seem to advertise ;-). > > -- > John Bokma j3b > > Blog: http://johnbokma.com/ Perl Consultancy: http://castleamber.com/ > Perl for books: http://johnbokma.com/perl/help-in-exchange-for-books.html > -- > http://mail.python.org/mailman/listinfo/python-list > General readability is a farce. If it was true we would only have one section to the library. Different people enjoy reading, and can comprehend better in different ways. THat's why some people are super verbose - hell, just look at this here post! :) -- http://mail.python.org/mailman/listinfo/python-list
Re: using masks and numpy record arrays
On 5/25/11 3:27 PM, Catherine Moroney wrote:
Hello,
I am trying to work with a structured array and a mask, and am encountering some
problems.
You will want to ask numpy questions on the numpy mailing list:
http://www.scipy.org/Mailing_Lists
For example:
>>> xtype = numpy.dtype([("n", numpy.int32), ("x", numpy.float32)])
>>> a = numpy.zeros((4), dtype=xtype)
>>> b = numpy.arange(0,4)
>>> a2 = numpy.zeros((4), dtype=xtype)
>>> mask = numpy.where(b%2 == 0)
>>> a2[:]["n"] += b ! this changes the values of a2
>>> a[mask]["n"] += b[mask] ! this does not change the values of a
>>> a2
array([(0, 0.0), (1, 0.0), (2, 0.0), (3, 0.0)],
dtype=[('n', '>> a
array([(0, 0.0), (0, 0.0), (0, 0.0), (0, 0.0)],
dtype=[('n', '
Only the final [] on the left-hand side of the assignment actually turns into a
.__setitem__() call to the object that is the result of the expression to its
left. a[mask] makes a copy while a2[:] makes a view.
You could do
a["n"][mask] += b[mask]
since a["n"] will also make a view and the .__setitem__() on it will propagate
back to the original memory.
--
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
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On 5/24/2011 1:39 PM, D'Arcy J.M. Cain wrote: [snip] One of my favorite quotes (not sure if it was about Perl or APL) is "I refuse to use a programming language where the proponents of it stick snippets under each other's nose and say 'I bet you can't guess what this does.'" I dunno. That sounds about like how most programming course exams are written, no? The point is that puzzling through arcane bits of code are crucial to learning any language. It's a valuable exercise. -- http://mail.python.org/mailman/listinfo/python-list
Re: super() in class defs?
On Wed, 25 May 2011 12:31:33 -0600, Ian Kelly wrote: > I would recommend against using super() in general. > > http://fuhm.net/super-harmful/ If you actually read that article, carefully, without being fooled by the author's provocative ex-title and misleading rhetoric, you will discover that super is not harmful. What is harmful is making unjustified assumptions about what super does, and about the code you are calling, and hence misusing super. You have to read all the way to the bottom of the article to see the author say in the TODO section: "Give some examples of why super really is necessary sometimes" Even before that, you will read why *not* using super often fails badly. If James Knight, the author, is correct that super is harmful, it seems that you're in trouble because *not using super* is also harmful. If you search the mailing lists of [email protected], you will find a debate between James and Guido van Russum where James eventually acknowledges that he is wrong to call super harmful. There's a reason that he has changed the title of the page from "Python's Super Considered Harmful" to the damning-with-faint-praise "Python's Super is nifty, but you can't use it". The new title is also *simply wrong*, because you can use it. James even tells you what you need to do to use it correctly. The truth is that for multiple inheritance, you better be using super or your code is probably buggy (unless you manually duplicate what super does for you). And for single inheritance, it makes no difference whether you use super or not. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
On 25/05/2011 21:54, Ian Kelly wrote: On Wed, May 25, 2011 at 2:00 PM, MRAB wrote: You're opening the file in text mode, and seeking relative to the end of the file is not allowed in text mode, presumably because the file contents have to be decoded, and, in general, seeking to an arbitrary position within a sequence of encoded bytes can have undefined results when you attempt to decode to Unicode starting from that position. The strange thing is that you _are_ allowed to seek relative to the start of the file. I think that with text files seek() is only really meant to be called with values returned from tell(), which may include the decoder state in its return value. What do you mean by "may include the decoder state in its return value"? It does make sense that the values returned from tell() won't be in the middle of an encoded sequence of bytes. -- http://mail.python.org/mailman/listinfo/python-list
Re: English Idiom in Unix: Directory Recursively
On Wed, 25 May 2011 09:26:11 +0200, Thorsten Kampe wrote: > Naming something in the terms of its implementation details (in this > case recursion) is a classical WTF. *If* that's true, it certainly doesn't seem to apply to real-world objects. Think about the exceptions: microwave oven vacuum cleaner oven fries electric car chain saw flintlock rifle air gun vulcanised rubber kerosene heater aluminium foil diamond saw gas stove wood stove four-wheel drive car incandescent light bulb electric razor unleaded petrol to mention only a few. Naming the thing after the implementation would often seem to be *good advice*, not bad. We often do care about implementations. You really do need to know whether the car you drive uses leaded or unleaded. Being able to swap implementations without changing the interface is an abstraction that doesn't apply all the time, in either code or real life. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: English Idiom in Unix: Directory Recursively
On Wed, 25 May 2011 00:06:06 +0200, Rikishi42 wrote: > On 2011-05-24, Steven D'Aprano > wrote: I think that is a patronizing remark that under-estimates the intelligence of lay people and over-estimates the difficulty of understanding recursion. >>> >>> Why would you presume this to be related to intelligence? The point >>> was not about being *able* to understand, but about *needing* to >>> understand in order to use. >> >> Maybe they don't "need" to understand recursion. So what? > > I think you should read the earlier posts again, this is drifting so far > from what I intended. > > What I mean is: I'm certain that over the years I've had more than one > person come to me and ask what 'Do you wish to delete this directory > recursively?' meant. BAut never have I been asked to explain what 'Do > you wish to delete this directory and it's subdirs/with all it's > contents?' meant. Never. I know many people who have no idea what a directory is, let alone a subdirectory, unless it's the phone directory. They're non-computer users. Once they start using computers, they quickly work out what the word means in context, or they ask and get told, and then they've learned a new word and never need ask again. This is a good thing. The idiom of "recursively delete" is no different. Of course some people will have to learn a new term in order to make sense of it. So what? > Do you know many people who incinerate leaves and branches in their > garden? I burn them. I know many people who incinerate leaves in an incinerator. Or at least they used to, until the government here banned it. It might only have been a 44 gallon drum with holes punched in the side, but they still called it an incinerator. I learned that word from my father, who left school at 14 to work in a shoe shop. He isn't especially educated, doesn't read much beyond the daily tabloid, and thinks Benny Hill is the height of wit. But he's not an idiot and even at 72 is capable of learning new words. >> Do they need to know the words "microwave oven" when they could be >> saying "invisible rays cooking thing"? > > The word oven has existed for ages, microwave is just a name for the > type of oven. Not even a description, just a name. Why do you think they're called "microwave ovens" instead of "fizzbaz ovens"? Could it possibly have something to do with the fact that they cook with microwaves? So not actually "just a name" at all. It's a jargon description of the implementation of the oven. >> I wonder whether physicists insist that cars should have a "go faster >> pedal" because ordinary people don't need to understand Newton's Laws >> of Motion in order to drive cars? > > Gas pedal. Pedal was allraedy known when the car was invented. The > simple addition of gas solved that need. What's a gas pedal? Is that some strange American term for what most of the English-speaking world knows as the accelerator? *wink* > Oh, and it's break pedal, not descellarator. (sp?) That would be brake, and decelerator. >> Who are you to say that people shouldn't be exposed to words you deem >> that they don't need to know? > > I'm one of the 'people'. You say exposed to, I say bothered/bored with. You can't force people to learn new words, although you would be surprised how even the most disinterested, lazy speaker manages to pick up vocabulary without even being aware of it. But nor do you have to pander to the slackers. They can learn the word, or not, I don't care. If I'm writing for an audience of children, or English as a second language, or the otherwise linguistically challenged, I'll simplify my vocabulary appropriately. For everyone else, I'll use an ordinary adult vocabulary, and that includes the word "recursion" or "recursive". It's hardly technical jargon -- I've found a discussion of gangsta rap that uses it. Even children understand the concept of recursion (self-reference). People put it in comedies like Blazing Saddles and Space Balls! How difficult is it to put a name to the concept? > I have nothing against the use of a proper, precise term. And that word > can be a complex one with many, many sylables (seems to add value, > somehow). > > But I'm not an academic, so I don't admire the pedantic use of terms > that need to be explained to 'lay' people. Pedantic... that's another one of those academic words that need to be explained to lay people, isn't it? As is academic itself, and in fact "lay people". Who uses "lay people" in conversation? Conversation -- another one of those four syllable words that should be avoided, since we have "talk". I don't remember that last time I've heard Bazza or Jimbo say "I was on the Internet having a conversation on Jabber", do you? Oh, actually I do. So much for that argument. > widespread, usually shorter and much simpler one for it. A pointless > effort if pointless, even when comming from a physicist. :-) I think you *grossly* underesti
Re: Why did Quora choose Python for its development?
On Wed, 25 May 2011 07:01:07 -0500, John Bokma wrote: > if Python is really so much better than Python [Perl] > readability wise, why do I have such a hard time dropping > Perl and moving on? My guess is that you have an adversarial view of computer languages, therefore after investing so much time and energy and, most importantly, self-image into becoming a Perl programmer, dropping it and moving on would be tantamount to admitting to yourself that you were "wrong" to have wasted so many years on the wrong language. Whether it is objectively "wrong" or not rarely enters into these things. That *you personally* can't or won't let go of Perl says nothing about the relative readability of Perl and Python code. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, 25 May 2011 08:01:38 +1000, Chris Angelico wrote:
> On Wed, May 25, 2011 at 3:39 AM, D'Arcy J.M. Cain
> wrote:
>> When I first looked at Perl it looked like line noise. When I first
>> looked at Python it looked like pseudo-code.
>
> When I first looked at assembly language it looked like random junk left
> behind in memory. When I first looked at COBOL it looked like ... COBOL.
> Doesn't make either of them better or worse.
Er, yes it does.
Writing code is primarily for *human readers*. Once you've compiled the
code once, the computer never need look at it again, but human being come
back to read it over and over again, to learn from it, or for
maintenance. We rightfully value our own time and convenience as more
valuable than that of the computer's, which is why we use programming
languages at all, instead of having custom-made hardware built for every
task we want the computer to do:
"I have to rename a file before August 2015, but the rename itself needs
to be done in under a picosecond. Know any bespoke chip manufacturers who
do small runs?"
From that perspective, COBOL is an improvement on assembly, which is why
there are probably still more COBOL programmers around than people who
work exclusively on assembly.
Sometimes we compromise, or even subvert, that trade-off: for speed
critical code where we do care more about the computer's time than our
own, or for esoteric languages designed to be as hard to read as
possible. My personal favourites, Oook and Whitespace.
But generally, people spend more time reading code than writing it,
therefore we should weigh "ease of reading" higher than "ease of
writing". (My guess is, the weights should be about 5:1.)
> Pseudo-code is not a viable language for a computer to parse,
Only because "pseudo-code" implies that the code is ambiguous or
otherwise cannot be parsed. If it could be, it wouldn't be *pseudo*, it
would be real code (possibly for some compiler that hasn't been written
yet).
> but it's a
> good language for scribbling down comments in. That doesn't necessarily
> mean that a programming language that's "closer to" pseudo-code is good.
That depends on the nature of pseudo-code. "Pseudo-assembly" has all the
disadvantages of assembly with none of the advantages, i.e. it doesn't
actually work. So in that sense, pseudo-code is not necessarily a good
thing nor a bad thing.
But in general conversation, pseudo-code is usually implied to mean that
the language is as close to human language as you can make it, while
still be parsable by a compiler.
> And verbosity doesn't necessarily equate to quality; for instance, when
> I'm working in both Python and PHP, I find it FAR tidier to use Python's
> {1:2,3:4] notation than PHP's array(1=>2,3=>4) - but on the flip side, I
> would prefer to have program structure defined by keywords like "if" and
> "while" than obscure random line noise. (Fortunately, most sane
> languages do indeed use keywords there.)
True. That's one of the limitations of the xtalk family of languages
derived from Apple's (defunct) Hypertalk: it's awfully verbose, which is
good for newbies but not quite so good for experts.
--
Steven
--
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Re: Python 3.2 bug? Reading the last line of a file
Thanks for the guidance - it was indeed an issue with reading in
binary vs. text., and I do now succeed in reading the last line,
except that I now seem unable to split it, as I demonstrate below.
Here's what I get when I read the last line in text mode using 2.7.1
and in binary mode using 3.2 respectively under IDLE:
2.7.1
Name31/12/2009 0 0 0
3.2
b'Name\t31/12/2009\t0\t0\t0\r\n'
if, under 2.7.1 I read the file in text mode and write
>>> x = lastLine(fn)
I can then cleanly split the line to get its contents
>>> x.split('\t')
['Name', '31/12/2009', '0', '0', '0\n']
but under 3.2, with its binary read, I get
>>> x.split('\t')
Traceback (most recent call last):
File "", line 1, in
x.split('\t')
TypeError: Type str doesn't support the buffer API
If I remove the '\t', the split now works and I get a list of bytes
literals
>>> x.split()
[b'Name', b'31/12/2009', b'0', b'0', b'0']
Looking through the docs did not clarify my understanding of the
issue. Why can I not split on '\t' when reading in binary mode?
Sincerely
Thomas Philips
--
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Re: super() in class defs?
On Wednesday, May 25, 2011 10:54:11 AM UTC-7, Jess Austin wrote: > I may be attempting something improper here, but maybe I'm just going > about it the wrong way. I'm subclassing > http.server.CGIHTTPRequestHandler, and I'm using a decorator to add > functionality to several overridden methods. > > def do_decorate(func): > . def wrapper(self): > . if appropriate(): > . return func() > . complain_about_error() > . return wrapper > > class myHandler(CGIHTTPRequestHandler): > . @do_decorate > . def do_GET(self): > . return super().do_GET() > . # also override do_HEAD and do_POST > > My first thought was that I could just replace that whole method > definition with one line: > > class myHandler(CGIHTTPRequestHandler): > . do_GET = do_decorate(super().do_GET) > > That generates the following error: > > SystemError: super(): __class__ cell not found > > So I guess that when super() is called in the context of a class def > rather than that of a method def, it doesn't have the information it > needs. Right. Actually the class object itself doesn't even exist yet when super() is invoked. (It won't be created until after the end of the class statement block.) > Now I'll probably just say: > > do_GET = do_decorate(CGIHTTPRequestHandler.do_GET) > > but I wonder if there is a "correct" way to do this instead? Thanks! Well, since the class object isn't created until after the end of the class statement block, it's impossible to invoke super() on the class from inside the block. So there's only two ways to invoke super(): 1. like you did above, by calling it inside a method, and 2. call it beyond the end of the class statement, like this: class myHandler(CGIHTTPRequestHandler): pass myHandler.do_GET = do_decorate(super(myHandler).do_GET) I wouldn't call that correct, though. (I'm not even sure it'll work, since I don't have Python 3 handy to test it, but as far as I can tell it will.) It's just one of the quirks of Python's type system. I don't agree with Ian's recommendation not to use super() in general, but I'd probably agree that one should stick to using it only in its intended way (to invoke base-class methods directly). Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: super() in class defs?
On Wed, May 25, 2011 at 3:40 PM, Steven D'Aprano wrote: > If you actually read that article, carefully, without being fooled by the > author's provocative ex-title and misleading rhetoric, you will discover > that super is not harmful. What is harmful is making unjustified > assumptions about what super does, and about the code you are calling, > and hence misusing super. Yes. As others have noted, the problem is really multiple inheritance, not super. Super can be a useful tool, but unless you have taken some time to learn its intricacies, I think that it is best avoided so that it is not misused. > You have to read all the way to the bottom of the article to see the > author say in the TODO section: > > "Give some examples of why super really is necessary sometimes" > > Even before that, you will read why *not* using super often fails badly. > If James Knight, the author, is correct that super is harmful, it seems > that you're in trouble because *not using super* is also harmful. Essentially, super can fail when you use it inconsistently. Not using super can fail when you have a diamond inheritance situation, or when you mix it with super. In this case, the OP is using super while inheriting from http.server.CGIHTTPServer, which does not use super, and so is inconsistent. > If you search the mailing lists of [email protected], you will find a > debate between James and Guido van Russum where James eventually > acknowledges that he is wrong to call super harmful. There's a reason > that he has changed the title of the page from "Python's Super Considered > Harmful" to the damning-with-faint-praise "Python's Super is nifty, but > you can't use it". Thanks. I found this quote from James that pretty much sums up my position perfectly: """ This is where I'm coming from: In my own code, it is very rare to have diamond inheritance structures. And if there are, even more rare that both sides need to cooperatively override a method. Given that, super has no necessary advantage. And it has disadvantages. - Backwards compatibility issues - Going along with that, inadvertent mixing of paradigms (you have to remember which classes you use super with and which you don't or your code might have hard-to-find errors). - Take your choice of: a) inability to add optional arguments to your methods, or b) having to use *args, **kwargs on every method and call super with those. - Having to try/catch AttributeErrors from super if you use interfaces instead of a base class to define the methods in use. """ > The new title is also *simply wrong*, because you can use it. James even > tells you what you need to do to use it correctly. Yes, you need to fundamentally alter the structure of your code to throw away any semblance of run-time argument checking by having every method that might conceivably be cooperatively inherited take *args, **kwargs. You also need to take care to always call super from such methods, even when it appears to be unnecessary. And don't forget to catch the AttributeError if the method is something other than __new__ or __init__ and the current class turns out to be the last one in the MRO that has it. In short, if you're using super and don't feel burdened by it, then you're probably using it incorrectly. > The truth is that for multiple inheritance, you better be using super or > your code is probably buggy (unless you manually duplicate what super > does for you). No. For diamond inheritance, you better be using super or your code is probably buggy. For typical diamond-less multiple inheritance, super is both unnecessary and tricky to use correctly. > And for single inheritance, it makes no difference whether > you use super or not. Right. It's unnecessary, so why saddle yourself with it? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
[email protected] wrote: Thanks for the guidance - it was indeed an issue with reading in binary vs. text., and I do now succeed in reading the last line, except that I now seem unable to split it, as I demonstrate below. Here's what I get when I read the last line in text mode using 2.7.1 and in binary mode using 3.2 respectively under IDLE: 3.2 b'Name\t31/12/2009\t0\t0\t0\r\n' under 3.2, with its binary read, I get --> x.split('\t') Traceback (most recent call last): File "", line 1, in x.split('\t') TypeError: Type str doesn't support the buffer API You are trying to split a bytes object with a str object -- the two are not compatible. Try splitting with the bytes object b'\t'. ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: bdist_wininst: install_script not run on uninstall
On 26/05/2011 5:28 AM, Wilbert Berendsen wrote: Hi, according to the docs the installer bdist_wininst creates will run the install-script on install with -install (which works perfectly) and on uninstall with the -remove argument (which seemingly never happens). However I want to cleanup some registry stuff on uninstall so I want the uninstall script to work. Studying the source code of the installer[1] in the Run_RemoveScript function... [1] http://svn.python.org/view/python/trunk/PC/bdist_wininst/install.c ... it checks for the line '%d Run Script: %s' in the log, which is there. But can anybody find out why the install script is not run? Works for me in the pywin32 install script - maybe you should make the smallest possible example that doesn't work and post the entire thing here? Mark -- http://mail.python.org/mailman/listinfo/python-list
Re: super() in class defs?
On May 25, 4:31 pm, Ian Kelly wrote: > Right. It's unnecessary, so why saddle yourself with it? FWIW, I expect to release a blog post tomorrow about the principal use cases for super() and how to use it effectively. With just a little bit of know-how, it can be an important tool in your Python toolkit. If any of the comp.lang.python readers want to review and comment on my latest draft, please email me and I'll send it to you directly. Cheers, Raymond Hettinger my email address is listed at http://users.rcn.com/python/download/Descriptor.htm -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On Wed, 25 May 2011 17:30:48 -0400, [email protected] wrote: > On 5/24/2011 1:39 PM, D'Arcy J.M. Cain wrote: [snip] >> One of my favorite quotes (not sure if it was about Perl or APL) is "I >> refuse to use a programming language where the proponents of it stick >> snippets under each other's nose and say 'I bet you can't guess what >> this does.'" > I dunno. That sounds about like how most programming course exams are > written, no? > The point is that puzzling through arcane bits of code are crucial to > learning > any language. It's a valuable exercise. You seem to miss the point that a good language shouldn't make it possible to write arcane code that needs to be puzzled out. Although in fairness, what's arcane to me might be straightforward to you... and vice versa. In that sense, there probably aren't any "good languages", because it is impractical to have a language that cannot be obfuscated in any way. Nevertheless, we can distinguish "less good" from "more good" in languages in the sense of readability. The fact that some languages not just allow such obfuscation but encourage it makes the language great for puzzles but not so good for when you actually want to get work done and have to deal with code written by someone else. *Especially* if they're significantly smarter, or dumber, than you. Worst of all is dealing with code written by somebody who *thinks* they're smarter but is actually dumber. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
On 26/05/2011 00:25, [email protected] wrote: Thanks for the guidance - it was indeed an issue with reading in binary vs. text., and I do now succeed in reading the last line, except that I now seem unable to split it, as I demonstrate below. Here's what I get when I read the last line in text mode using 2.7.1 and in binary mode using 3.2 respectively under IDLE: 2.7.1 Name31/12/2009 0 0 0 3.2 b'Name\t31/12/2009\t0\t0\t0\r\n' if, under 2.7.1 I read the file in text mode and write x = lastLine(fn) I can then cleanly split the line to get its contents x.split('\t') ['Name', '31/12/2009', '0', '0', '0\n'] but under 3.2, with its binary read, I get x.split('\t') Traceback (most recent call last): File "", line 1, in x.split('\t') TypeError: Type str doesn't support the buffer API If I remove the '\t', the split now works and I get a list of bytes literals x.split() [b'Name', b'31/12/2009', b'0', b'0', b'0'] Looking through the docs did not clarify my understanding of the issue. Why can I not split on '\t' when reading in binary mode? x.split('\t') tries to split on '\t', a string (str), but x is a bytestring (bytes). Do x.split(b'\t') instead. -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
On May 25, 3:14 pm, John Bokma wrote: > Ethan Furman writes: > > Terry Reedy wrote: > >> On 5/25/2011 8:01 AM, John Bokma wrote: > > >>> to. Like I already stated before: if Python is really so much better > >>> than Python readability wise, why do I have such a hard time dropping > >>> Perl and moving on? > > >> [you meant 'than Perl'] You are one of the people whose brain fits > >> Perl (or vice versa) better than most. So enjoy it. Ignore anyone > >> who says otherwise. > > > +1 > > > If everybody's brain worked the same, we wouldn't have so many > > different languages to choose from. > > So, this means that in general language readability is not as clear cut > as some seem to advertise ;-). > I only know a tiny bit of Perl but I think you may prefer it because it gives you some advantages in short term but you have to pay more than it's worth (arguably) in the long term. When you sit down to write a new program, it's easier to do than in python because it's quicker to type and, of the proverbial "many ways", you chose the ones that suit your taste better. However, when you sit down to read someone else's code, it's harder to read because you don't know the intent of their authors. If they had different taste for idioms or formatting style than you do, you will chalk it up to them being bad programmers and having bad coding or formatting style, so it's not perceived as a perl's failing. Python way has more of an emphasis on everyone agreeing on some preferred, standard idioms so that everyone can pick up each others' code quickly. Similarly, when we write in english, we have conventions of, for instance, capitalizing at the start of a sentence and having a period at the end of it, and following rules of grammar. However, if I'm writing notes for my own use, I might write: similarly when we write in english we have conventions of eg capitalizing at start of sentence and having period at the end & following rules of grammar but since i'm writing for my own use maybe it's easier to write in lower caps and use 3 spaces at the end of sentences, since no-ones has to read it but me? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
MRAB wrote: On 26/05/2011 00:25, [email protected] wrote: Thanks for the guidance - it was indeed an issue with reading in binary vs. text., and I do now succeed in reading the last line, except that I now seem unable to split it, as I demonstrate below. Here's what I get when I read the last line in text mode using 2.7.1 and in binary mode using 3.2 respectively under IDLE: 2.7.1 Name31/12/2009000 3.2 b'Name\t31/12/2009\t0\t0\t0\r\n' if, under 2.7.1 I read the file in text mode and write x = lastLine(fn) I can then cleanly split the line to get its contents x.split('\t') ['Name', '31/12/2009', '0', '0', '0\n'] but under 3.2, with its binary read, I get x.split('\t') Traceback (most recent call last): File "", line 1, in x.split('\t') TypeError: Type str doesn't support the buffer API If I remove the '\t', the split now works and I get a list of bytes literals x.split() [b'Name', b'31/12/2009', b'0', b'0', b'0'] Looking through the docs did not clarify my understanding of the issue. Why can I not split on '\t' when reading in binary mode? x.split('\t') tries to split on '\t', a string (str), but x is a bytestring (bytes). Do x.split(b'\t') instead. Instances of the bytes class are more appropriately called 'bytes objects' rather than 'bytestrings' as they are really lists of integers. Accessing a single element of a bytes object does not return a bytes object, but rather the integer at that location; i.e. --> b'xyz'[1] 121 Contrast that with the str type where --> 'xyz'[1] 'y' ~Ethan~ -- http://mail.python.org/mailman/listinfo/python-list
Re: Unable to make ironpython run in browser with silverlight
You need to run it from a web-server; it doesn't work when running from file:// due to Silverlight's security sandbox. Read the comments on my blog-post, it mentions the web-server there. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python-list Digest, Vol 92, Issue 221
> Writing code is primarily for *human readers*. Once you've compiled the > code once, the computer never need look at it again, but human being come > back to read it over and over again, to learn from it, or for > maintenance. We rightfully value our own time and convenience as more > valuable than that of the computer's, which is why we use programming > languages at all, instead of having custom-made hardware built for every > task we want the computer to do: Not only the code itself, but, hopefully, embedded comments help even non-authors of the code to understand, maintain and improve it. Programming books that include examples often spend many pages dissecting even short segments of the code to tutor would-be developers how it works and what it does. Well written code in any language, with accompanying comments, is invaluable for anyone who has the need or interest to Understand and maintain it. My (ancient) books about object-oriented programming were used to teach hundreds of computer science students in universities all over the world, and the stressed the importance of embedded comments. How many times has any programmer looked at (even inscrutable) code with accompanying comments and hasn't said to themselves "so that's how to do it, or that's what it does". It's time to stop having flame wars about languages and embrace programmers who care enough about possible future readers of their code to thoroughly comment it. Comments are far more valuable than the actual language in which the code is written, IMHO. Sent from my iPad. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
On Wed, May 25, 2011 at 3:52 PM, MRAB wrote:
> What do you mean by "may include the decoder state in its return value"?
>
> It does make sense that the values returned from tell() won't be in the
> middle of an encoded sequence of bytes.
If you take a look at the source code, tell() returns a long that
includes decoder state data in the upper bytes. For example:
>>> data = b' ' + '\u0302a'.encode('utf-16')
>>> data
b' \xff\xfe\x02\x03a\x00'
>>> f = open('test.txt', 'wb')
>>> f.write(data)
7
>>> f.close()
>>> f = open('test.txt', 'r', encoding='utf-16')
>>> f.read()
Traceback (most recent call last):
File "", line 1, in
File "c:\python32\lib\codecs.py", line 300, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
File "c:\python32\lib\encodings\utf_16.py", line 61, in _buffer_decode
codecs.utf_16_ex_decode(input, errors, 0, final)
UnicodeDecodeError: 'utf16' codec can't decode bytes in position 6-6:
truncated data
The problem of course is the initial space, throwing off the decoder.
We can try to seek past it:
>>> f.seek(1)
1
>>> f.read()
'\ufeff\u0302a'
But notice that since we're not reading from the beginning of the
file, the BOM has now been interpreted as data. However:
>>> f.seek(1 + (2 << 65))
73786976294838206465
>>> f.read()
'\u0302a'
And you can see that instead of reading from position
73786976294838206465 it has read from position 1 starting in the "read
a BOM" state. Note that I wouldn't recommend doing anything remotely
like this in production code, not least because the value that I
passed into seek() is platform-dependent. This is just a
demonstration of how the seek() value can include decoder state.
Cheers,
Ian
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Re: Cherrypy
I wrote http://drdobbs.com/showArticle.jhtml?articleID=199102936&queryText=query way back then. It might be of some help. If you have any specific questions, feel free to post them to the group. -- http://mail.python.org/mailman/listinfo/python-list
Re: Odp: Re: Strange behaviour of input() function (Python 3.2)
On Wednesday 25 May 2011 06:27:52 sunrrrise wrote: > Ok, another time I'd like to thank you for your help. I gave > up, I'm going to get used to IDLE GUI... at least this one > works! With IDLE, after any changes to the program, you are asked to "save file". IDLE knows that a file in python needs to be saved before it can be run! If you use Notepad, it does not know that Python programs need to be saved to disk before they can be executed. So you should remember to save them first. To use IDLE is a good choice, particularly if you are a beginner! OldAl. -- Algis http://akabaila.pcug.org.au/StructuralAnalysis.pdf -- http://mail.python.org/mailman/listinfo/python-list
Re: Unable to make ironpython run in browser with silverlight
On May 26, 9:44 am, Jimmy Schementi wrote: > You need to run it from a web-server; it doesn't work when running from > file:// due to Silverlight's security sandbox. Read the comments on my > blog-post, it mentions the web-server there. I see.. But here: http://silverlighttest.zzl.org/silverlighttest.html , it runs from a web server, but still gives error. And it has the same source code as your example, except that I replace repl.py with the direct link, as you advise on your blog. I think the problem is with this part: http://github.com/jschementi/pycon2010/ raw/master/repl.py"> Because when I delete it, it runs properly. Do you know why is that? -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question about SQLite + Python and twitter
On May 25, 2011, at 2:17 PM, Jayme Proni Filho wrote: > Helo guys, > > I'm building a local application for twitter for my brother's store. I'm in > the beginning and I have some newbie problems, so: > > I create a table called tb_messages with int auto increment and varchar(140) > fields; > I did three SQL funcionts, insert_tweet, delete_tweet, select_tweet > > select_tweet is use for getting messages for sending them to twitter; > > My problem is: How can i make my select_tweet works at the same time that > insert or delete funcions. I just got to work when I stop select function. > > I would like to do my app works all the time. Hi Jayme, You need to provide a lot more information for us to be able to help you. Some suggestions -- http://www.istf.com.br/perguntas/#beprecise bye Philip -- http://mail.python.org/mailman/listinfo/python-list
Re: Unable to make ironpython run in browser with silverlight
On May 26, 9:44 am, Jimmy Schementi wrote: > You need to run it from a web-server; it doesn't work when running from > file:// due to Silverlight's security sandbox. Read the comments on my > blog-post, it mentions the web-server there. I see.. But here: http://silverlighttest.zzl.org/silverlighttest.html , it runs from a web server, but still gives error. And it has the same source code as your example, except that I replace repl.py with the direct link, as you advise on your blog. I think the problem is with this part: http://github.com/jschementi/ pycon2010/ raw/master/repl.py"> Because when I delete it, it runs properly. Do you know why is that? -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
Steven D'Aprano writes: > On Wed, 25 May 2011 07:01:07 -0500, John Bokma wrote: > >> if Python is really so much better than Python [Perl] >> readability wise, why do I have such a hard time dropping >> Perl and moving on? > > My guess is that you have an adversarial view of computer languages, Well, it's clear that you are indeed the fuckwit I suspected you are. What's a pity is that you are so vocal in this group and to me at least makes it a way less pleasant experience to read this group. Get a life. Or better, just fuck off and die. It will improve both the world and the Python community, of which you are nothing but a little, smelly shitstain. -- John Bokma j3b Blog: http://johnbokma.com/Perl Consultancy: http://castleamber.com/ Perl for books:http://johnbokma.com/perl/help-in-exchange-for-books.html -- http://mail.python.org/mailman/listinfo/python-list
Re: English Idiom in Unix: Directory Recursively
On Thu, May 26, 2011 at 8:58 AM, Steven D'Aprano wrote: > ... For everyone else, I'll use an > ordinary adult vocabulary, and that includes the word "recursion" or > "recursive". Overheard yesterday: "Our conversation was recursing..." I don't know what they were talking about, but I'm pretty sure it wasn't the technical details of a function's implementation, given that one of the people concerned was anything but a computer programmer (I don't know about the other). It's a perfectly good word, useful in many contexts. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Python-list Digest, Vol 92, Issue 221
On Thu, May 26, 2011 at 10:58 AM, Richard Parker wrote: > It's time to stop having flame wars about languages and embrace programmers > who care enough about possible future readers of their code to thoroughly > comment it. Comments are far more valuable than the actual language in which > the code is written, IMHO. The problem with comments (and documentation in general) is that they are often imperfect. If the code is absolutely opaque but it has a comment next to it, you still have that niggling doubt: has the comment been updated whenever the code has? Was it even accurate in the first place? (Comments often say what a piece of code _ought_ to do, but the code might have a bug in it. And sometimes, that bug ends up being part of the function's definition, and people depend on it.) I'd rather have both - reasonably readable code AND a comment, where the comment explains the intent behind the code. // allow space for frobnostication height += BTN_HEIGHT; Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did Quora choose Python for its development?
> Get a life. Or better, just fuck off and die. It will improve both the > world and the Python community, of which you are nothing but a little, > smelly shitstain. That abuse is entirely unwelcome in this community, against any person. Please desist. If you find any contributing members so difficult to deal with, please don't respond at all. -- \ “We have met the enemy and he is us.” —Walt Kelly, _Pogo_ | `\1971-04-22 | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Parse config file and command-line arguments, to get a single collection of options
Howdy all, Python's standard library has modules for configuration file parsing (configparser) and command-line argument parsing (optparse, argparse). I want to write a program that does both, but also: * Has a cascade of options: default option values, overridden by config file options, overridden by command-line options. * Reads a different, or even additional, configuration file if specified on the command-line (e.g. --config-file foo.conf) and yet still obeys the above cascade. * Allows a single definition of an option (e.g. logging level) to define the same option for parsing from configuration files and the command line. * Unifies the parsed options into a single collection for the rest of the program to access without caring where they came from. How can I achieve this with minimum deviation from the Python standard library? (For anyone interested in gaining StackOverflow points, I'm also asking this as a question there so feel free to post answers on that site http://stackoverflow.com/questions/6133517/parse-config-file-and-command-line-arguments-to-get-a-single-collection-of-optio>.) -- \ “Apologize, v. To lay the foundation for a future offense.” | `\ —Ambrose Bierce, _The Devil's Dictionary_, 1906 | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Puzzled by list-appending behavior
In playing with lists of lists, I found the following: (In 3.1, but the same happens also in 2.7) list = [1,2,3] list.append ( [4,5,6] ) x = list x -> [1,2,3,[4,5,6]] as expected. But the shortcut fails: list=[1,2,3] x = list.append( [4,5,6] ) x -> nothing Can someone explain this to me? Uncle Ben -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.2 bug? Reading the last line of a file
[email protected] writes: > Looking through the docs did not clarify my understanding of the > issue. Why can I not split on '\t' when reading in binary mode? You can split on b'\t' to get a list of byteses, which you can then decode if you want them as strings. You can decode the bytes to get a string and then split on '\t' to get strings. >>> b'tic\ttac\ttoe'.split(b'\t') [b'tic', b'tac', b'toe'] >>> b'tic\ttac\ttoe'.decode('utf-8').split('\t') ['tic', 'tac', 'toe'] -- http://mail.python.org/mailman/listinfo/python-list
Re: Puzzled by list-appending behavior
Uncle Ben writes: > Can someone explain this to me? Yes, the documentation for that function (‘list.append’) can explain it. In short: if a method modifies the instance, that method does not return the instance. This policy holds for the built-in types, and should be followed for user-defined types also. -- \ “[I]t is impossible for anyone to begin to learn that which he | `\thinks he already knows.” —Epictetus, _Discourses_ | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Puzzled by list-appending behavior
On Wed, May 25, 2011 at 9:46 PM, Uncle Ben wrote: > In playing with lists of lists, I found the following: > > (In 3.1, but the same happens also in 2.7) > > list = [1,2,3] > list.append ( [4,5,6] ) Note the lack of output after this line. This indicates that list.append([4,5,6]) returned None. Contrast this with, say, list.pop(). > x = list > x -> > [1,2,3,[4,5,6]] > as expected. > > But the shortcut fails: > > list=[1,2,3] > x = list.append( [4,5,6] ) > x -> > nothing > > Can someone explain this to me? The append() method does *not* return the now-appended-to list. It is a mutator method that modifies the list object in-place; per convention, it therefore returns None to reinforce its side-effecting nature to the user (the interactive interpreter by default does not display None expression results); analogous methods in other languages return void. list.remove(), list.sort(), and list.extend() similarly return None rather than the now-modified list. Cheers, Chris -- http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
