date:20070912

TheFlyingDutchman a écrit :
 Python user and advocate Bruce Eckel is disappointed with the
 additions (or lack of additions) in Python 3:
 
 http://www.artima.com/weblogs/viewpost.jsp?thread=214112
 

I'd say Mr Eckel fails to graps some of the great points about Python's 
object model - the rant about the use of 'self' is a sure clue.
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Re: An ordered dictionary for the Python library?

On Sep 12, 9:33 am, Mark Summerfield [EMAIL PROTECTED]
wrote:
 I feel that Python lacks one useful data structure: an ordered
 dictionary.

 I find such data structures v. useful in C++. I know that in Python
 the sort function is v. fast, but often I prefer never to sort but
 simply to use an ordered data structure in the first place.
 (I'm aware that for ordered lists I can use the bisect module, but I
 want an ordered key-value data structure.)

 I think other people must find such things useful. There are three
 implementations on the Python Cookbook site, and one on PyPI, all in
 pure Python (plus I have my own implementation, also pure Python).

 I would suppose that it would be better if it was implemented in C---
 for example, my own pure Python ordered dict loads data about eight
 times slower than the built-in dict. Nonetheless, I still find it
 worth using for the convenience it offers.

 Do other Python programmers feel this lack? Is this worth a PEP?


Yes, this is a serious lack in the standard library.

 Michele Simionato

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Re: getattr and static vs. instantiated

tvaughan a écrit :
 Hi,
 
 Let's say I have:
 
 class Persistable(object):
 
 __attrs__ = {}
 
 def __getattr__(self, name):
 if name in self.__attrs__:
 return self.__attrs__[name]['value']
 else:
 return Object.__getattr__(self, name)
 
 def __setattr__(self, name, value):
 if name in self.__attrs__:
 self.__attrs__[name]['value'] = value
 else:
 Object.__setattr__(self, name, value)
 
 And the I have:
 
 class Person(Persistable):
 
 __storm_table__ = 'person'
 
 id = Int(primary=True)
 
 __attrs__ = {
 'name': {
 'lang': 'en',
 'value': Unicode(),
 },
 }
 
 def __init__(self):
 self.id = int(random.random() * 1000)
 
 I can do this:
 
 person = Person()
 person.name = 'Jane Smith'
 
 But I cannot do:
 
 Person.name = 'Jane Smith'

yes, you can. But it won't do the same thing.

 or use Person.name in a Storm query like:
 
 Person.name == 'Jane Smith'

It will obviously raise an AttributeError if the class Person doesn't 
have a 'name' attribute.

 __getattr__ is only called when using an instantiated class,

A class's '__getattr__' method is only triggered when looking up 
attributes on an instance of the class, yes.

 and
 never, it seems, in a static case. Why? How do I work around this?

Since classes are instances of their type, the obvious solution would be 
to define a custom metaclass implementing __getattr__. I didn't try, but 
it might work.

Now is this the best thing to do is another question. You seems not to 
be aware of the descriptor protocol - which is used to implement methods 
and properties. This lets you define 'smart' attributes. You'll find 
relevant documentation here:
http://docs.python.org/ref/descriptors.html
and here:
http://users.rcn.com/python/download/Descriptor.htm


Also, you seem to be trying to roll your own ORM. There are already 
quite a few existing ones - SQLAlchemy being probably the best one 
already, and also a good base (no pun) for building your own solutions.

HTH
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Re: An ordered dictionary for the Python library?

2007-09-12 Thread stef

Mark Summerfield wrote:
 I feel that Python lacks one useful data structure: an ordered
 dictionary.

 I find such data structures v. useful in C++. I know that in Python
 the sort function is v. fast, but often I prefer never to sort but
 simply to use an ordered data structure in the first place.
 (I'm aware that for ordered lists I can use the bisect module, but I
 want an ordered key-value data structure.)

 I think other people must find such things useful. There are three
 implementations on the Python Cookbook site, and one on PyPI, all in
 pure Python (plus I have my own implementation, also pure Python).

 I would suppose that it would be better if it was implemented in C---
 for example, my own pure Python ordered dict loads data about eight
 times slower than the built-in dict. Nonetheless, I still find it
 worth using for the convenience it offers.

 Do other Python programmers feel this lack? Is this worth a PEP?

   
Yes I think it's really useful,
(or at least I'm used to it in other languages ;-)
If you're going to extend the dictionary,
there's one other flag I'm continuously missing:
case-insensitive key.

cheers,
Stef Mientki

 [I originally asked about this on the P3K mailing list, but then
 realised that it isn't version-specific really.]

   
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Re: Generating HTML

Evan Klitzke a écrit :
 On Wed, 2007-09-12 at 01:33 -0300, Sebastian Bassi wrote:
 Hello,

 What are people using these days to generate HTML? I still use
 HTMLgen, but I want to know if there are new options. I don't
 want/need a web-framework a la Zope, just want to produce valid HTML
 from Python.
 
 It's not applicable for everything, but if you're planning on using
 Python to generate web pages you should really be using Cheetah
 templates. Very simple to use template system that is also very
 powerful, and you don't need to use it in conjunction with a heavy web
 application framework. See http://www.cheetahtemplate.org/
 

Same for Mako (http://www.makotemplates.org), which has IMHO a much 
nicer syntax (Cheetah looks too much like line noise IMHO).
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How can I work on VIM for python code such as cscope for C code?

2007-09-12 Thread Evan

Hi, guys ~~

How can i work on VIM for python code?  I use cscope plugin on VIM for
C code before, it helps me to  different function and search C
variable where it is defined.

I'm now starting to learn python, and I'd like to know how works on
VIM.

I saw that the VIM is support python such as syntax highlighting,
autocmd,etc. but I really want to know if it can work with TAG.

Do I need to downlaod other software/plugin?

Thanks,

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Re: Help With PyParsing of output from win32pdhutil.ShowAllProcesses()

2007-09-12 Thread Paul McGuire

On Sep 11, 1:12 pm, Steve [EMAIL PROTECTED] wrote:
 Hi All (especially Paul McGuire!)

 Could you lend a hand in the grammar and paring of the output from the
 function win32pdhutil.ShowAllProcesses()?

 This is the code that I have so far (it is very clumsy at the
 moment) :

snip

 Many thanks!

 Steve

Steve -

Well, your first issue is not a pyparsing one, but one of redirecting
stdout.  win32pdhutil.ShowAllProcesses does not *return* the output
you listed, it just prints it to stdout.  The value returned is None,
which is why you are having trouble parsing it (even after converting
None to a string).

For you to parse out this data, you will need to redirect stdout to a
string buffer, run ShowAllProcesses, and then put stdout back the way
it was.  Python's cStringIO module is perfect for this:


from cStringIO import StringIO
import sys
import win32pdhutil

save_stdout = sys.stdout
process_info = StringIO()
sys.stdout = process_info

win32pdhutil.ShowAllProcesses()
sys.stdout = save_stdout
sProcess_Info = process_info.getvalue()


*Now* you have all that data captured into a processable string.

As others have mentioned, this data is pretty predictably formatted,
so pyparsing may be more than you need.  How about plain old split?


for line in sProcess_Info.splitlines()[1:]:
data = line.split()
print data


Done!

Still have an urge to parse with pyparsing?  Here are some comments on
your grammar:

- Your definition of process_name was not sufficient on my system.  I
had some processes running whose names includes numeric digits and
other non-alphas.  I needed to modify process_name to:

process_name = pyparsing.Word(pyparsing.alphanums+_.-)

- Similarly, some of my values returned by ShowAllProcesses had
negative values, so your definition of integer needs to comprehend an
optional leading '-' sign.  (This actually sounds like a bug in
win32pdhutil - I don't think any of these listed quantities should
report a negative value.)

- Whenever I have integers in a grammar, I usually convert them to
ints at parse time, using a parse action:

integer.setParseAction( lambda tokens : int(tokens[0]) )

- The tabular format of this data, and the fact that the initial entry
in each row appears to be a label of some sort invites the use of the
pyparsing Dict class.  I note that you are already trying to extract
keys from the parsed data, so it looks like you are already thinking
along these lines.  (Unfortunately, it is very likely you will get
duplicate keys, since process names do not have to be unique - this
will involve some loss of data in this example.)  The Dict class auto-
generates results names in the parsed results.  Dict turns out to be
awkward to use directly, so I added the dictOf method to simplify
things.  The concept of dictOf(keyExpr,valueExpr) is parse a list of
dict entries, each of which is a key-value pair; while parsing, label
each entry with the parsed key.  In your example, this would be:

ProcessList = heading + pyparsing.dictOf(process_name,
pyparsing.OneOrMore(integer) )

The key is a leading process_name, and the value is the following list
of integers.  With this, you can print out the results using:


data = ProcessList.parseString(sProcess_Info)

print data keys:, data.keys()
for k in sorted(data.keys()):
print k, :, data[k]


Getting:

BCMWLTRY : [684, 0, 0, 0, 54353920, 53010432]
CLI : [248, 0, 0, 0, 171941888, 153014272]
D4 : [2904, 0, 0, 0, 37527552, 36413440]
F-StopW : [2064, 0, 0, 0, 33669120, 30121984]
...
(again, note that the multiple entries for CLI have been reduced to
a single dict entry)

You could get similar results using something like:

data = dict((vals[0],vals[1:]) for vals in
map(str.split,sProcess_Info.splitlines()))

But then you would never have learned about dictOf!

Enjoy!
-- Paul

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Re: Excel process still running after program completion - SOLVED

2007-09-12 Thread Tal Einat

On Sep 11, 8:29 pm, Chris [EMAIL PROTECTED] wrote:
 On Sep 11, 1:26 pm, Chris [EMAIL PROTECTED] wrote:



  On Sep 11, 12:59 pm, Hamilton, William  [EMAIL PROTECTED] wrote:

From: Chris

I have a python script that is driving Excel and using the win32com
module. However, upon program completion there's still an Excel.exe
process running in the background that I must terminate through Task
Manager. Reading up on other threads indicate that maybe I still have
some Excel objects referenced within my code. Is this why the process
doesn't terminate?

The related (I hope) parts of my code is here.

x1App = Dispatch(Excel.Application)
Book1 = x1App.Workbooks.Open(ExcelLogPath+\\outputLog-template.xls)
x1App.Visible = 1
for sheets in Book1.Worksheets:
 if sheets.Name == file_name:
  sheetExists = True
if sheetExists != True:
 activeSheet =
Book1.Worksheets.Add(After=Book1.Worksheets(1))
 activeSheet.Name = file_name
 testNum[file_name] = 0
Book1.Worksheets(file_name).Select()
Book1.ActiveSheet.Cells(1+(testNum[file_name]*20),1).Value = Original
File Name
Book1.ActiveSheet.Cells(2+(testNum[file_name]*20),1).Value =
file_name
Book1.ActiveSheet.Pictures().Insert(output).Select()
Book1.SaveAs(Filename=path)
x1App.ActiveWorkbook.Close(SaveChanges=0)
x1App.Quit()
del x1App
del Book1
del activeSheet

What am I missing?

   In my Excel projects, I terminate it with:

   xlBook.Close()
   xlApp.Quit()

   I haven't had a problem with Excel staying open after the program ends.

   (On a tangent, I want to find the person who thought it was a good idea
   to use the same symbol in a font for 1, l, and I and do some unpleasant
   things.)

   --
   -Bill Hamilton

  That doesn't really fix the problem as I'm pretty sure its identical
  code for
  x1App.ActiveWorkbook.Close(SaveChanges=0)

  I think where my problem lies is within my for each loop where I
  search to see if the worksheet with the name already exists
  for sheets in Book1.Worksheets:
   if sheets.Name == file_name:
 sheetExists = True

  Since I'm assuming that it creates objects for each of the sheets and
  I don't delete them...

 Which I'm right... I added this code and now there's no EXCEL.EXE
 process after my script completes

 for sheets in Book1.Worksheets:
   if sheets.Name == file_name:
 sheetExists = True
   sheets = None
   del sheets

You just need to 'del sheets' once after the loop, no need to do it in
every iteration. After your original loop the 'sheets' variable still
pointed to the last sheet object, probably causing it not to be
properly cleaned up. This is the only thing that your change fixes,
but it is simpler (and more readable) to just do it once after the
loop.

(Please add SOLVED or FIXED to the subject when your issue has been
resolved, so that people like me don't read the whole thread only to
find that their help is no longer needed.)

- Tal

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Re: Difference between two times (working ugly code, needs polish)

2007-09-12 Thread Iain King

On Sep 12, 1:31 am, Shawn Milochik [EMAIL PROTECTED] wrote:
  I suppose really oneDay should be a global (i.e. outside the function
  definition). Apart from that it would be hard to improve on: obvious,
  easy to read, in short - pythonic.

  Are you concerned about daylight savings? That could certainly introduce
  a whole new level of complexity into the problem. Let's hope not ...

 I'm not concerned with DST; this is a script which checks my Ebay
 auctions (I have some things for sale), and sends me e-mail whenever
 someone bids. It's run by cron every half hour -- it keeps me from
 compulsively checking my auctions. ^_^

 In any case, DST isn't an issue because the same machine generates
 both timestamps, and all I use it for is to stop displaying auctions
 after they are 10 days old, so I don't get all my old crap filling up
 the alert e-mail or skewing the total dollar amount for all active
 auctions.

 Thanks.
 Shawn

Just to be picky - your function returns the number of days between
two dates, but it's called isOld, which looks like it should return a
boolean.  i.e.  it looks like it would be used as:

if not isOld(auctionDate, currentTime):
checkForBid()

rather than how I assume it is used:

if isOld(auctionDate, currentTime) = 10:
checkForBid()

I'd call it daysDiff or something similar, or make it more specific so
that it works like the first block of code above:

ONEDAY = 60*60*24
OLDNESS_THRESHOLD = 10

def isOld(lastUpdate, runTimeStamp):
lastUpdate = time.mktime(time.strptime(lastUpdate, %Y-%m-%d_%H:
%M))
runTimeStamp = time.mktime(time.strptime(runTimeStamp, %Y-%m-%d_
%H:%M))
return (runTimeStamp - lastUpdate) / ONEDAY  =  OLDNESS_THRESHOLD

if not isOld(auctionDate, currentTime):
checkForBid()

Iain

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setattr vs readonly property

2007-09-12 Thread james_027

hi,

My main purpose for using setattr(object, attr, value) for assign
values from a dict that has some keys that may not be present on some
object's attibute, which makes it work for me. My problem is dealing
with read only attribute like sample_attribute =
property(f_get=_get_sample_attribute). what approach should I use? Or
is my first approach In the first place right?

Thanks
james

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Re: need scsh in a wikip article

2007-09-12 Thread [EMAIL PROTECTED]

 someone please add scsh there.

Why can't YOU add scsh or I am missing something??

Andrey

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Re: setattr vs readonly property

james_027 wrote:

 hi,
 
 My main purpose for using setattr(object, attr, value) for assign
 values from a dict that has some keys that may not be present on some
 object's attibute, which makes it work for me. My problem is dealing
 with read only attribute like sample_attribute =
 property(f_get=_get_sample_attribute). what approach should I use? Or
 is my first approach In the first place right?

Since read-only properties are very concise written as this:


class Foo(object):
   @property
   def ro_prop(self):
   return whatever

I'd say that's the way to go - using __getattr__ for this will lead to
rather convoluted code IHMO.

Diez
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Re: Get Only the Last Items in a Traceback

Am Wed, 12 Sep 2007 02:09:28 + schrieb [EMAIL PROTECTED]:

 I'm running code via the exec in context statement within a much
 larger program.  What I would like to do is capture any possible
 errors and show a pretty traceback just like the Python interactive
 interpreter does, but only show the part of the traceback relating to
 the code sent to exec.
 
 For example here is the code I'm using:
 
 try:
 exec code
 except Exception,Err:
 traceback.print_exc()
 
 Which gives me something like this when it catches an exception:
 
 Traceback (most recent call last):
   File /py, line 843, in run
 semi_safe_exec.safe_eval(code.replace('\r',''),context,5)
   File .py, line 400, in safe_eval
 exec_timed(code, context, timeout_secs)
   File .py, line 353, in exec_timed
 exec code in context
   File string, line 7, in ?
   File string, line 5, in func2
   File string, line 2, in func1
 ZeroDivisionError: integer division or modulo by zero
 
 What I want to print instead is just something like:
 
 Traceback (most recent call last):
   File string, line 7, in ?
   File string, line 5, in func2
   File string, line 2, in func1
 ZeroDivisionError: integer division or modulo by zero
 
 Thanks in advance for the help.
 
 -Greg
 
 P.S. if it matters, for this example, code in exec code is:
 
 def func1():
 print 7/0
 
 def func2():
 func1()
 
 func2()

Your assessment is wrong. You only get the extra lines in the traceback if
you don't immediately wrap the exec statement in a try ... except block:

$ cat snip_traceback1.py
import traceback

def alpha():
try:
beta()
except Exception, e:
traceback.print_exc()

def beta():
gamma()

def gamma():
exec s in {}

s =  
def delta():
epsilon()

def epsilon():
1/0
delta()


if __name__ == __main__:
alpha()

$ python snip_traceback1.py 
Traceback (most recent call last):
  File snip_traceback1.py, line 5, in alpha
beta()
  File snip_traceback1.py, line 10, in beta
gamma()
  File snip_traceback1.py, line 13, in gamma
exec s in {}
  File string, line 7, in module
  File string, line 3, in delta
  File string, line 6, in epsilon
ZeroDivisionError: integer division or modulo by zero

So the first step is to move the try ... except closer to the exec:

$ cat snip_traceback2.py
import traceback

def alpha():
beta()

def beta():
gamma()

def gamma():
try:
exec s in {}
except Exception, e:
traceback.print_exc()

s =  
def delta():
epsilon()

def epsilon():
1/0
delta()


if __name__ == __main__:
alpha()

$ python snip_traceback2.py 
Traceback (most recent call last):
  File snip_traceback2.py, line 11, in gamma
exec s in {}
  File string, line 7, in module
  File string, line 3, in delta
  File string, line 6, in epsilon
ZeroDivisionError: integer division or modulo by zero

You are almost there. Now let's strip off the outermost traceback:

$ cat snip_traceback3.py
import sys
import traceback

def alpha():
beta()

def beta():
gamma()

def gamma():
try:
exec s in {}
except Exception, e:
etype, value, tb = sys.exc_info()
traceback.print_exception(etype, value, tb.tb_next)

s =  
def delta():
epsilon()

def epsilon():
1/0
delta()


if __name__ == __main__:
alpha()

$ python snip_traceback3.py 
Traceback (most recent call last):
  File string, line 7, in module
  File string, line 3, in delta
  File string, line 6, in epsilon
ZeroDivisionError: integer division or modulo by zero

Heureka.

Peter
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MemoryError on reading mbox file

2007-09-12 Thread Christoph Krammer

Hello everybody,

I have to convert a huge mbox file (~1.5G) to MySQL.

I tried with the following simple code:

for m in mailbox.mbox(fileName):

  msg  = m.as_string(True)
  hash = md5.new(msg).hexdigest()

  try:
dbcurs.execute(INSERT INTO archive (hash, msg) VALUES (%s,
%s), (hash, msg))
  except MySQLdb.OperationalError, err:
print %s  Error (%d): %s % (file, err[0], err[1])
  else:
print %s: Message successfully added to database % (hash,
spamSource)

The problem seems to be the size of file, every time I try to execute
the script, after about 2 messages, the following error occurs:

Traceback (most recent call last):
  File email_to_mysql_mbox.py, line 21, in module
for m in mailbox.mbox(fileName):
  File /usr/lib/python2.5/mailbox.py, line 98, in itervalues
value = self[key]
  File /usr/lib/python2.5/mailbox.py, line 70, in __getitem__
return self.get_message(key)
  File /usr/lib/python2.5/mailbox.py, line 633, in get_message
string = self._file.read(stop - self._file.tell())
MemoryError

My system has 512M RAM and 768M swap, which seems to run out at an
early stage of this. Is there a way to clean up memory for messages
already processed?

Thanks and regards,
 Christoph

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Re: need scsh in a wikip article

2007-09-12 Thread Timofei Shatrov

On Wed, 12 Sep 2007 02:10:09 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED]
tried to confuse everyone with this message:

 someone please add scsh there.

Why can't YOU add scsh or I am missing something??


Maybe he is banned?

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|It's us against millions and we can't take them all... |  ue il   |
|But we can take them on!   | @ma  |
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Re: Generating HTML

Sebastian Bassi wrote:

 Hello,
 
 What are people using these days to generate HTML? I still use
 HTMLgen, but I want to know if there are new options. I don't
 want/need a web-framework a la Zope, just want to produce valid HTML
 from Python.

KID, Genshi, Mako. And a bazillion others. I prefer the first two ones
because the force you to use valid XML and produce HTML/XHMTL out of that.

Diez
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Re: function to do dynamic import?

Am Wed, 12 Sep 2007 11:54:51 +1000 schrieb bambam:

 def gim():
 exec global gamel
 exec import gamel
 
 Unfortunately, does not have the desired effect.
 Steve.

Both statements have to be part of a single exec:

def gim():
modulename = gamel # determined at runtime
exec global %s; import %s % (modulename, modulename)

It may work, but it is still a bad idea to create global variables with a
name not known until runtime.

Peter
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Re: Get Only the Last Items in a Traceback

2007-09-12 Thread Michael Ströder

[EMAIL PROTECTED] wrote:
 I'm running code via the exec in context statement within a much
 larger program.  What I would like to do is capture any possible
 errors and show a pretty traceback just like the Python interactive
 interpreter does, but only show the part of the traceback relating to
 the code sent to exec.
 
 For example here is the code I'm using:
 
 try:
 exec code
 except Exception,Err:
 traceback.print_exc()

Guess what's argument limit is for. Excerpt from the Python docs:

 snip 
print_exc(  [limit[, file]])
This is a shorthand for print_exception(sys.exc_type, sys.exc_value,
sys.exc_traceback, limit, file). (In fact, it uses sys.exc_info() to
retrieve the same information in a thread-safe way instead of using the
deprecated variables.)
 snip 

Ciao, Michael.
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Re: setattr vs readonly property

 My main purpose for using setattr(object, attr, value) for assign
 values from a dict that has some keys that may not be present on some
 object's attibute, which makes it work for me. My problem is dealing
 with read only attribute like sample_attribute =
 property(f_get=_get_sample_attribute). what approach should I use? Or
 is my first approach In the first place right?

You could try catching the exception thrown when you attempt to assign
to a read-only attribute. Although you may get consistency issues. ie
your object doesn't have all the details from the dict, but the
calling code expects them to be set. Perhaps you should provide
setter methods for the properties also, so that your objects
internal state gets set correctly.

eg: in your class declaration:

def setfoo(self, value):
   # Add code here to check 'value' and set internal 'foo' state correctly
   self._foo = value

def getfoo(self):
   return self._foo

foo = property(setfoo, getfoo)
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Re: MemoryError on reading mbox file


 My system has 512M RAM and 768M swap, which seems to run out at an
 early stage of this. Is there a way to clean up memory for messages
 already processed?

It may be that Python's garbage collection isn't keeping up with your app.

You could try periodically forcing it to run. eg:

import gc
gc.collect()

You can also finetune the GC settings and check what is using up your memory.

More info here: http://docs.python.org/lib/module-gc.html
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newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Charles Fox

I've just started playing around with Python, as a possible
replacement for a mix of C++, Matlab and Lisp.  The language looks
lovely and clean with one huge exception:  I do a lot of numerical
modeling, so I deal with objects (like neurons) described
mathematically in papers, by equations like
a_dot = -k(a-u)
In other languages, this translates nicely into code, but as far as I
can tell, Python needs the ugly:
self.a_dot = -self.k(self.a-self.u)
For large equations this is going to make my code seriously unreadable
to the point of needing to switch back to Matlab -- and it seems to go
against everything else about python's simplicity and elegance.  Am I
missing something?  Is there something like a 'with' command that lets
me set the scope, like

with self:
  .a_dot = -.k(.a-.u)

It's premature to make language suggestions as I am new to the
language, but I would have though that making a 'with self' explicit
in all methods would have been neat, so I could just write
  .a_dot = -.k(.a-.u)
which would still avoid confusion with local function variables, since
'.a' is different from 'a'.

Please help if I am missing something -- this looks like a great
language but I am going to mad trying to read numerical code full of
'self.'s breaking up the equations.

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Re: An ordered dictionary for the Python library?

2007-09-12 Thread thebjorn

On Sep 12, 9:33 am, Mark Summerfield [EMAIL PROTECTED]
wrote:
 I feel that Python lacks one useful data structure: an ordered
 dictionary.

 I find such data structures v. useful in C++. I know that in Python
 the sort function is v. fast, but often I prefer never to sort but
 simply to use an ordered data structure in the first place.
 (I'm aware that for ordered lists I can use the bisect module, but I
 want an ordered key-value data structure.)
[...]
 Do other Python programmers feel this lack? Is this worth a PEP?

I usually make a distinction between a sorted dict, where iteration
(and potentially positional indexing) happens in sorted key order; and
an ordered dict where items maintain insertion order. I use the latter
all the time, and e.g. Django's model metaclass does some minor magic
to overcome the fact that field-order is lost by the time your
metaclass gets control, since the attributes are passed as a regular
dict.

-- bjorn

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Re: newbie: self.member syntax seems /really/ annoying

 Please help if I am missing something -- this looks like a great
 language but I am going to mad trying to read numerical code full of
 'self.'s breaking up the equations.

You could try this in your functions:

s = self

Then you can use code like this: s.a_dot = s.k(s.a-s.u)

Another option, if you use the vars a lot in a given function, is to
copy them to local vars. This can also slightly speed up your code
(fewer member lookups).
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Re: newbie: self.member syntax seems /really/ annoying

On Sep 12, 12:21 pm, Charles Fox [EMAIL PROTECTED] wrote:
 I've just started playing around with Python, as a possible
 replacement for a mix of C++, Matlab and Lisp.  The language looks
 lovely and clean with one huge exception:  I do a lot of numerical
 modeling, so I deal with objects (like neurons) described
 mathematically in papers, by equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as far as I
 can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)
 For large equations this is going to make my code seriously unreadable
 to the point of needing to switch back to Matlab -- and it seems to go
 against everything else about python's simplicity and elegance.  Am I
 missing something?  Is there something like a 'with' command that lets
 me set the scope, like

 with self:
   .a_dot = -.k(.a-.u)

 It's premature to make language suggestions as I am new to the
 language, but I would have though that making a 'with self' explicit
 in all methods would have been neat, so I could just write
   .a_dot = -.k(.a-.u)
 which would still avoid confusion with local function variables, since
 '.a' is different from 'a'.

 Please help if I am missing something -- this looks like a great
 language but I am going to mad trying to read numerical code full of
 'self.'s breaking up the equations.

You can always use aliases

a = self.a
u = self.u
...

or even s = self

or play games with dictionaries.


 Michele Simionato

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Re: Python 3K or Python 2.9?

2007-09-12 Thread Ivan Voras


Bruno Desthuilliers wrote:

TheFlyingDutchman a écrit :

Python user and advocate Bruce Eckel is disappointed with the
additions (or lack of additions) in Python 3:

http://www.artima.com/weblogs/viewpost.jsp?thread=214112


I'd say Mr Eckel fails to graps some of the great points about Python's 
object model - the rant about the use of 'self' is a sure clue.


What does self have to do with an object model? It's an 
function/method argument that might as well be hidden in the compiler 
without ever touching the role it has (if not, why?). I agree that it's 
needless noise in a language.




signature.asc
Description: OpenPGP digital signature
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Re: newbie: self.member syntax seems /really/ annoying

On 9/12/07, David [EMAIL PROTECTED] wrote:
  Please help if I am missing something -- this looks like a great
  language but I am going to mad trying to read numerical code full of
  'self.'s breaking up the equations.

 You could try this in your functions:

 s = self

 Then you can use code like this: s.a_dot = s.k(s.a-s.u)

 Another option, if you use the vars a lot in a given function, is to
 copy them to local vars. This can also slightly speed up your code
 (fewer member lookups).


Also, there is no rule saying you need to use self, it's just a
convention. You can declare your methods like this instead:

def foo(s, arg1, arg2):
  s.a_dot = s.k(s.a-s.u)
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Re: newbie: self.member syntax seems /really/ annoying

 
 with self:
   .a_dot = -.k(.a-.u)
 
 It's premature to make language suggestions as I am new to the
 language, but I would have though that making a 'with self' explicit
 in all methods would have been neat, so I could just write
   .a_dot = -.k(.a-.u)
 which would still avoid confusion with local function variables, since
 '.a' is different from 'a'.
 
 Please help if I am missing something -- this looks like a great
 language but I am going to mad trying to read numerical code full of
 'self.'s breaking up the equations.

This is a FAQ - and the short answer is: no, you don't miss anything, and
it's not going change. If you want, you can shorten the expressions like
this:

s = self
s.a * s.b

Or choose any other valid name, e.g. the underscore.

Another (yet rather ugly) alternative would be to push the names into the
global namespace. But that could of course create major mayhem! So take
this with a huge grain of salt:

globals().update(self.__dict__)

a * b

Diez
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Re: newbie: self.member syntax seems /really/ annoying

Charles Fox a écrit :
 I've just started playing around with Python, as a possible
 replacement for a mix of C++, Matlab and Lisp.  The language looks
 lovely and clean with one huge exception:  I do a lot of numerical
 modeling, so I deal with objects (like neurons) described
 mathematically in papers, by equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as far as I
 can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)

ugliness is a very subjective notion. As far as I'm concerned, I hate 
the m_myMember C++ convention, and have always used the 'this' (or 
whatever it's named) pointer/reference/pseudo-reference/whatever in 
languages where it's implicit - because I don't like such an important 
thing to be implicit.

  self.a_dot = - self.k(self.a - self.u)

 For large equations this is going to make my code seriously unreadable

Ok, but this is another problem.

 to the point of needing to switch back to Matlab -- and it seems to go
 against everything else about python's simplicity and elegance.  Am I
 missing something? 

Yes.

 Is there something like a 'with' command that lets
 me set the scope, like
 
 with self:
   .a_dot = -.k(.a-.u)

Nope. There's a 'with' statement, but it has nothing to do with this.

The obvious solution to your problem is to make local references to the 
needed attributes at the start of your method, ie:

def some_calc(self, whatever):
   k = self.k # yes, it works for methods too
   a = self.a
   u = self.u

   self.a_dot = -k(a-u)

 It's premature to make language suggestions as I am new to the
 language, but I would have though that making a 'with self' explicit
 in all methods would have been neat, so I could just write
   .a_dot = -.k(.a-.u)
 which would still avoid confusion with local function variables, since
 '.a' is different from 'a'.
 
 Please help if I am missing something -- this looks like a great
 language but I am going to mad trying to read numerical code full of
 'self.'s breaking up the equations.

The mandatory 'self' (FWIW, you can name it as you want, 'self' is just 
a convention) has long been the topic of lot of debates. While I do 
understand your motivations, there are actually good reasons for this 
design choice, but understanding these reasons requires some knowledge 
of Python's object model internals. As far as I'm concerned, I'm quite 
happy with the current design, but I don't do much maths !-)

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Re: Difference between two times (working ugly code, needs polish)

2007-09-12 Thread Shawn Milochik

 Just to be picky - your function returns the number of days between
 two dates, but it's called isOld, which looks like it should return a
 boolean.  i.e.  it looks like it would be used as:

 if not isOld(auctionDate, currentTime):
 checkForBid()

 rather than how I assume it is used:

 if isOld(auctionDate, currentTime) = 10:
 checkForBid()

 I'd call it daysDiff or something similar, or make it more specific so
 that it works like the first block of code above:

You're absolutely right; I started writing it with one purpose in mind
and changed it midstream. I actually renamed it yesterday to dayDiff.
;o)

Shawn
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Re: Generating HTML

2007-09-12 Thread jkn

I used to use Cheetah, but have switched recently to Jinja:

http://jinja.pocoo.org/

Mainly this is because the syntax is similar to Django's templates,
and eventually I plan on migrating to Django.

jon N

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RE: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Ryan Ginstrom

 On Behalf Of Charles Fox
 described mathematically in papers, by equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as 
 far as I can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)

In addition to the other advice you've received, if you don't need to
preserve state, you could avoid the self business by putting your
functions in a module instead of an object.

def k(a):
return a**3

def dot(a, u)
return -k(a-u)

Python modules are also objects, so they can serve in place of class
instances much of the time.

Regards,
Ryan Ginstrom

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Re: unexpected behavior: did i create a pointer?

neoedmund a écrit :
 On Sep 7, 4:07 pm, gu [EMAIL PROTECTED] wrote:
(snip pb and code)
 now, in the second for cycle and in functionA() i only 'touch' copyOfA
 (altering it). as i don't touch the variable a, i expect it not to be
 affected by any change, but copyOfA acts like a pointer to a and
 altering copyOfA's values result in altering the values of a, so the
 result that i expect is:
(snip)
 no language act like want you tought, or the assignment operation will
 be too expensive.

IIRC, php4 was doing copies for arrays...
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Re: Python 3K or Python 2.9?

2007-09-12 Thread Bjoern Schliessmann

Ivan Voras wrote:

 What does self have to do with an object model? It's an
 function/method argument that might as well be hidden in the
 compiler without ever touching the role it has (if not, why?). I
 agree that it's needless noise in a language.

If this was needless, why do C++ and Java have the this pointer?

Regards,


Björn

-- 
BOFH excuse #390:

Increased sunspot activity.

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Re: Compiler Python

2007-09-12 Thread Bjoern Schliessmann

Bruno Desthuilliers wrote:
 Bjoern Schliessmann a écrit :

 I'm not really about the syntax of your question,
 ^(sure)
 
 lol !-)

;) It wasn't mean ironically, I really forgot the sure.

Regards,


Björn

-- 
BOFH excuse #322:

Your Pentium has a heating problem - try cooling it with ice cold
water.(Do not turn of your computer, you do not want to cool down
the Pentium Chip while he isn't working, do you?)

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Sea-or-land test

2007-09-12 Thread kpalamartchouk

Could you advise if there exists a simple package, containing function
that would take geographic coordinates and return information on
whether this point belongs to land or sea? No great accuracy is needed
-- I am interested in just major features, like those seen on coarse
world maps.

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Re: How can I work on VIM for python code such as cscope for C code?

2007-09-12 Thread Joe Riopel

On 9/12/07, Evan [EMAIL PROTECTED] wrote:
 Hi, guys ~~

 How can i work on VIM for python code?  I use cscope plugin on VIM for
 C code before, it helps me to  different function and search C
 variable where it is defined.

Change to the top level directory that contains your python source
files, and do
find -name '*.py'  cscope.files
cscope -b

Then it should work.

 Do I need to downlaod other software/plugin?

You might, if do you not have the cscope_maps.vim plugin. If not you
can get it http://cscope.sourceforge.net/cscope_vim_tutorial.html and
just put it in your vim plugins directory.
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Re: Get Only the Last Items in a Traceback

Am Wed, 12 Sep 2007 11:21:48 +0200 schrieb Michael Ströder:

 [EMAIL PROTECTED] wrote:
 I'm running code via the exec in context statement within a much
 larger program.  What I would like to do is capture any possible
 errors and show a pretty traceback just like the Python interactive
 interpreter does, but only show the part of the traceback relating to
 the code sent to exec.
 
 For example here is the code I'm using:
 
 try:
 exec code
 except Exception,Err:
 traceback.print_exc()
 
 Guess what's argument limit is for. Excerpt from the Python docs:

Unfortunately traceback.print_exc(limit=N) trims the wrong end of the
traceback:

 def alpha(): beta()
... 
 def beta(): gamma()
... 
 def gamma(): 1/0
... 
 try:
... alpha()
... except:
... traceback.print_exc()
... 
Traceback (most recent call last):
  File stdin, line 2, in module
  File stdin, line 1, in alpha
  File stdin, line 1, in beta
  File stdin, line 1, in gamma
ZeroDivisionError: integer division or modulo by zero
 try:
... alpha()
... except:
... traceback.print_exc(limit=1)
... 
Traceback (most recent call last):
  File stdin, line 2, in module
ZeroDivisionError: integer division or modulo by zero


Peter
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Re: cpython list str method for floats

2007-09-12 Thread Bjoern Schliessmann

[david] wrote:

 Leaving aside the question of why str should return repr,

str doesn't return repr. str returns a nice string
representation of an object. This nice string representation of
a list is the opening square bracket, the repr of its contents
seperated by comma, and the closing square bracket.
prayer-millHere, it *only* makes sense to have a list printed
with the repr of their contents./prayer-mill

 13.301 is not 'the float in full precision':
 it is an arbitrary translation of the float.

Do you know IEEE 754?
 
 The idea that 13.3 is a 'rounded' value for the number,
 and that 13.301 is not a 'rounded' value of
 the number, is a common error of intuitive mathematics.

I'm intrigued how /you/'d explain this, please do explain.

 I hope that when you say that this is a FAQ, you don't
 mean that the community has solidified on this naive
 interpretation :~)

No, I mean that your complaint is not at all new. Reading the
archives you could have learned a lot about this topic.

Regards,


Björn

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BOFH excuse #247:

Due to Federal Budget problems we have been forced to cut back on
the number of users able to access the system at one time. (namely
none allowed)

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SIP examples

2007-09-12 Thread Srijit Kumar Bhadra

I am trying to learn SIP (http://www.riverbankcomputing.co.uk/sip/)
these days. I do not see any examples similar to SWIG. 
http://www.swig.org/doc.html
has lots of examples. But for SIP, all I see is a reference guide
(http://www.riverbankcomputing.com/Docs/sip4/sipref.html).
Examples help. Where can I get examples for SIP 4.7?

Regards,
/Srijit

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Re: Generating HTML

2007-09-12 Thread Walter Dörwald

Sebastian Bassi wrote:

 Hello,
 
 What are people using these days to generate HTML? I still use
 HTMLgen, but I want to know if there are new options. I don't
 want/need a web-framework a la Zope, just want to produce valid HTML
 from Python.

If you want something that works similar to HTMLgen, you could use XIST:
http://www.livinglogic.de/Python/xist/

Servus,
   Walter
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Re: Python 3K or Python 2.9?

2007-09-12 Thread Stefan Behnel

Bjoern Schliessmann wrote:
 What does self have to do with an object model? It's an
 function/method argument that might as well be hidden in the
 compiler without ever touching the role it has (if not, why?). I
 agree that it's needless noise in a language.
 
 If this was needless, why do C++ and Java have the this pointer?

Be careful when you use the word needless in the context of Java.

Stefan
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Re: Generating HTML

2007-09-12 Thread Stefan Behnel

Sebastian Bassi wrote:
 What are people using these days to generate HTML? I still use
 HTMLgen, but I want to know if there are new options. I don't
 want/need a web-framework a la Zope, just want to produce valid HTML
 from Python.

There's also lxml.html, which has straight forward support for generating HTML
and comes with a lot of nice goodies for HTML handling:

http://codespeak.net/lxml/dev/lxmlhtml.html#creating-html-with-the-e-factory

Note that this requires lxml 2.0, which is currently in alpha status.

Stefan
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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Jeremy Sanders

Charles Fox wrote:

 I've just started playing around with Python, as a possible
 replacement for a mix of C++, Matlab and Lisp.  The language looks
 lovely and clean with one huge exception:  I do a lot of numerical
 modeling, so I deal with objects (like neurons) described
 mathematically in papers, by equations like

I thought it was horrible when I started, but now when looking at somebody
else's C++ code I find it very hard to work out whether something is a
global, a member or a local variable, unless they use some sort of naming
convention.

If you alias self as s, it's only two more characters per variable access,
which is the same as the C++ m_ naming convention.

-- 
Jeremy Sanders
http://www.jeremysanders.net/
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Spring Python 0.3.0 is released!

2007-09-12 Thread Goldfish

Spring Python (http://springpython.python-hosting.com) version 0.3.0
was released yesterday.

Key improvements include:
* Make the web components WSGI-compatible, firstly working with
CherryPy.
* Extend PetClinic to use database accounts and have password
encoding.
* Add an ExceptionTranslationFilter so PetClinic handles errors more
sophisticated.
* Relicense Spring Python underneath GPLv3.
* Generally, clean up the code and test cases. Also start using code
coverage tools to improve quality of testing.

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Re: Python Database Apps

2007-09-12 Thread Ed Leafe

On Sep 11, 2007, at 2:56 PM, [EMAIL PROTECTED] wrote:

 It's gonna be a desktop app.  The
 database engine is going to be the critical component.  I like sqlite
 so that I don't need a database server on the client side.  It would
 help though if there is a way to sync between multiple clients to a
 central server database.  That's the tough part.  To give you a better
 idea of what i'm trying to do, I am trying to write an app where
 multiple technicians have an issue tracker that is available both
 offline and online.  I was looking to use sqlite as the local side
 that would sync new and updated issues to a central server when
 online.  Any technician may work on any issue.  Generally they will
 not be working on the same issue at the same time.  The technicians
 are geographically diverse (anywhere in the southeast US, not in an
 office.)

As far as the server goes, you can't go wrong with PostgreSQL, as  
others have mentioned. I have more experience with MySQL, but their  
recent licensing changes have simply made it easier to go with  
Postgres, as I don't have to worry about which clause of which  
document I might be violating.

For the local data store, SQLite is far and away the best choice,  
since you don't have to use two types of data access, as you would if  
you went with SQL on the server and, say, pickling on the local.

If you create both data stores with the same structure, you can use  
UUIDs as your keys, along with a timestamp flag for records that are  
added or modified when disconnected so that you can re-sync later.  
You will have to handle conflicts (i.e., someone changed a record  
that another also changed while disconnected) on your own,  
implementing your own business logic to determine who wins, and how  
the conflicted data is handled.

I'll close with a plug for our product: Dabo. It is a desktop  
application framework with support for SQLite, PostgreSQL, MySQL,  
Firebird and Microsoft SQL Server databases. For disconnected data,  
you would simply define a local connection (to SQLite) and a remote  
connection (to your server database), and switch between the two  
depending on whether you are disconnected or not. The framework will  
handle the rest, allowing you to focus on the stuff that is unique to  
your app, such as the conflict resolution and business logic.

-- Ed Leafe
-- http://leafe.com
-- http://dabodev.com


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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Steven D'Aprano

On Wed, 12 Sep 2007 03:21:58 -0700, Charles Fox wrote:

 I've just started playing around with Python, as a possible replacement
 for a mix of C++, Matlab and Lisp.  The language looks lovely and clean
 with one huge exception:  I do a lot of numerical modeling, so I deal
 with objects (like neurons) described mathematically in papers, by
 equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as far as I
 can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)

I think you've been seriously mislead. You don't NEED self. That's only 
for writing classes.

Although Python is completely object oriented, and everything is an 
object, you don't have to put your code in classes.

Instead of doing something like this:

class Adder(object):
Pointless class to add things.
def __init__(self, value):
self.value = other
def add(self, other):
x = self.value + other
return float(x)

you don't need a class. Just write a function:

def add(x, other):
Function that adds other to x.
return float(x + other)

Here's how I would write your function above:

def function(a, u, k):
Calculate a_dot from a, u and k.
return -k(a-u)

And here is how I would use it:

a = 57 # or whatever...
u = 54
k = 3
a_dot = function(a, u, k)


See? Not a single self in sight.


You might also like to read about a strange, bizarre programming that 
forces you to put everything inside classes:

http://steve-yegge.blogspot.com/2006/03/execution-in-kingdom-of-nouns.html




-- 
Steven.
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Re: Python 3K or Python 2.9?

2007-09-12 Thread Duncan Booth

Ivan Voras [EMAIL PROTECTED] wrote:

 I'd say Mr Eckel fails to graps some of the great points about 
Python's
  
 object model - the rant about the use of 'self' is a sure clue.
 
 What does self have to do with an object model? It's an 
 function/method argument that might as well be hidden in the compiler 
 without ever touching the role it has (if not, why?). I agree that 
it's 
 needless noise in a language.

You could add some syntax to Python such that '.x' was equivalent to 
'first argument of current function.x' (either completely implicitly 
or with some surrounding block that lets you specify the assumed 
variable. 

That wouldn't break anything in the syntax but the general feeling of 
the Python community is that such a change would be undesirable as it is 
better to write the variable name out explicitly.

As for omitting 'self' from method definitions, at first site you might 
think the compiler could just decide that any 'def' directly inside a 
class could silently insert 'self' as an additional argument. This 
doesn't work though because not everything defined in a class has to be 
an instance method: static methods don't have a self parameter at all, 
class methods traditionally use 'cls' instead of 'self' as the name of 
the first parameter and it is also possible to define a function inside 
a class block and use it as a function. e.g.

class Weird:
   def factory(arg):
   Returns a function based on its argument

   foo = factory(foo)
   bar = factory(bar)
   del factory

When factory is called, it is a simple function not a method. If it had 
gained an extra parameter then either you would have to explicitly pass 
it an instance of a not yet defined class when calling it, or the 
compiler would have to somehow know that it had been defined with the 
extra parameter and add it.

Basically it all boils down to having a consistent set of rules. Ruby 
has one set of rules, but Python has a different set. Python's rules 
mean you can interchange functions and methods more easily [at a cost of 
having to write self out explicitly/with the advantage that you can 
easily see references to self](delete as preferred). There is no 
difference between:

class C:
   def method(self): pass

and

def foo(self): pass
class C: pass
C.method = foo

both of these result in effectively the same class (although the second 
one has a different name for the method in tracebacks).

That consistency really is important. Whenever I see a 'def' I know 
exactly what parameters the resulting function will take regardless of 
the context.

Another area to consider is what happens when I do:

foo = FooClass()

foo.bar(x)
# versus
f = foo.bar
f(x)

Both of these work in exactly the same way in Python: the self parameter 
is bound to the method when you access 'foo.bar', not when you make the 
call. That isn't the case in some other scripting languages. e.g. in 
Javascript the first one would call bar with the magic 'this' parameter 
set to foo, but in the second case it calls bar with 'this' set to the 
global object.

My point here is that in Python the magic is clearly defined and 
overridable (so we can have static or class methods that act 
differently).

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Re: An ordered dictionary for the Python library?

2007-09-12 Thread Steven D'Aprano

On Wed, 12 Sep 2007 07:33:45 +, Mark Summerfield wrote:

 I feel that Python lacks one useful data structure: an ordered
 dictionary.
 
 I find such data structures v. useful in C++.
[snip]


Personally, I've never missed an ordered dict. What do people use them 
for?

In fact, I'm not sure what people mean by ordered dicts. I assume they 
mean the keys are ordered, not the values. But ordered by what? Insertion 
order? Modification order? Alphabetical order? 


-- 
Steven.
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Re: An ordered dictionary for the Python library?

On Sep 12, 2:42 pm, Steven D'Aprano [EMAIL PROTECTED]
cybersource.com.au wrote:
 On Wed, 12 Sep 2007 07:33:45 +, Mark Summerfield wrote:
 In fact, I'm not sure what people mean by ordered dicts. I assume they
 mean the keys are ordered, not the values. But ordered by what? Insertion
 order? Modification order? Alphabetical order?

Insertion order.

 M.S.

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Re: SIP examples

Srijit Kumar Bhadra wrote:

 I am trying to learn SIP (http://www.riverbankcomputing.co.uk/sip/)
 these days. I do not see any examples similar to SWIG.
 http://www.swig.org/doc.html has lots of examples. But for SIP, all I see
 is a reference guide
 (http://www.riverbankcomputing.com/Docs/sip4/sipref.html). Examples help.
 Where can I get examples for SIP 4.7?

Download pyqt, and look into it. Together with the reference, that's pretty
sufficient.

Diez
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Re: Python Database Apps

2007-09-12 Thread Goldfish

I use MySQL and also sqlite. However, I also use Spring Python (http://
springpython.python-hosting.com) to use both its DatabaseTemplate
utility class and also the remoting functionality. This way, I can
have the database code sitting on the server, and then export the data
access functions remotely to clients. It is also relatively easy to
swap out database engines.

For the record: Spring Python is my pet project. I use it myself, and
recommend it to others as well.

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Re: An ordered dictionary for the Python library?

2007-09-12 Thread Steven D'Aprano

On Wed, 12 Sep 2007 09:51:02 +0200, stef wrote:

 If you're going to extend the dictionary, there's one other flag I'm
 continuously missing: case-insensitive key.

Completely untested and probably buggy as anything, but here's an 
absolutely minimal case-insensitive dictionary.

class CaselessDict(dict):
def __setitem__(self, key, value):
super(CaselessDict, self).__setitem__(key.lower(), value)
def __getitem__(self, key):
return super(CaselessDict, self).__getitem__(key.lower())


-- 
Steven.
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Re: cpython list str method for floats

2007-09-12 Thread Duncan Booth

Bjoern Schliessmann [EMAIL PROTECTED] 
wrote:

 The idea that 13.3 is a 'rounded' value for the number,
 and that 13.301 is not a 'rounded' value of
 the number, is a common error of intuitive mathematics.
 
 I'm intrigued how /you/'d explain this, please do explain.

I think he is correct here: 13.301 is not exactly 
representable in IEEE 754. It is a rounded approximation to the true 
value just as is 13.3.

An argument can be made that instead of rounding the internal value to 
17 digits which is sufficient to ensure that you can roundtrip float-
string-float for all values, you could just round it to the minimum 
number of digits which guarantee the float-string-float roundtrip for 
that particular value.

Consider this as we gradually lose the more significant digits we see 
that last digit wasn't exactly 1 at all:

 13.3
13.301
 13.3-13
0.30071
 (13.3-13)*10-3
7.1054273576010019e-015

but why shouldn't Python do this instead?:

 13.3
13.3
 13.3-13
0.3
 (13.3-13)*10-3
7.1054273576e-015

These values will still roundtrip to the exact same internal 
representations. BTW, I didn't have to work too hard to figure out what 
that last value should be, the first is cut/paste from CPython, the 
second is what IronPython gives you.

I believe the claim is that using the full 17 digits ensures the round-
tripping works even if you serialise and deserialise on different 
systems, so perhaps we all pay a cost in our interactive sessions for 
something which should really be buried deep in IPC code.

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pythonesque constructs for c++

2007-09-12 Thread Josh

One of the best features of python is its ease of use, and the ease of use 
of its modules. Modules like os, os.path, and datetime are invaluable!

Does anyone know of analagous c++ libraries? It seems to me that most of the 
functionality of these modules could easily be replicated in c++. Before I 
go about doing that, I was just wondering if anyone knows if they already 
exist?

thanks,
Josh


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Is the wxPython list down?

Hi,

Does anyone know if the wxPython mailing list is having issues? I
subscribe to it and haven't seen anything come through since
09/06/2007. I went to ActiveState's archives and the last message
there is from the 7th (http://aspn.activestate.com/ASPN/Mail/Browse/
Threaded/wxPython-users).

Thanks,

Mike

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Re: Basic GUI

Don,

On Sep 11, 10:54 pm, Don Hanlen [EMAIL PROTECTED] wrote:
 I'm writing a simple GUI that:
 ..gets info via telnet protocol (and sends)
 ..gets info via http (and sends)
 ..gets user-info from (currently)
 ...Tkinter Text windoze
 ...Tkinter buttons and such
 ..displays info in various Tkinter windoze
 ...graphic AND text...

 I can accomplish all of these functions individually and now seem to
 need to set up multi-processes to combine 'em.  Back in my C days, I'd
 have used fork/exec to do so, but I'm confused by the number of
 modules available in Python.  Is there a best for portability and
 simplicity?  (Or am I on the wrong track here?)

 I could solve my problems with the following psuedo-code made into
 real code:
 
 import blah

 t = blah.fork(runthisprogram.py)

 #OK still in main
 t.sendinfo(info)
 info = t.receiveinfo()
 
 #runthisprogram.py
 def sendinfobacktopapa():
 ? eventhere
 def getinfofrompapa():
 ? eventhere
 

 It seems to me that propagating events *may* be the best way to
 communicate.  I'm wide open, including to non-multi-process solutions.

 Thanks for your comments, I searched old posts for a while, various
 other Python info-sources, and couldn't find an answer.
 --
 don


You can also use threads, which is a little bit more portable than
using Python's fork methodology, or so I've read. The concepts on this
page can be applied to any GUI toolkit you choose:
http://wiki.wxpython.org/LongRunningTasks

I've used them with wxPython, but iirc, Lutz does something quite
similar with Tkinter in his latest edition of Programming Python.

I think what Michele is referring to is the subprocess module, which
is also useful.

Mike

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Re: Sea-or-land test

On Sep 12, 6:54 am, [EMAIL PROTECTED] wrote:
 Could you advise if there exists a simple package, containing function
 that would take geographic coordinates and return information on
 whether this point belongs to land or sea? No great accuracy is needed
 -- I am interested in just major features, like those seen on coarse
 world maps.

This may be of use to you: http://cheeseshop.python.org/pypi/geopy

or http://blog.case.edu/bmb12/2006/09/geocoding_tools_for_python_and_caseclasses

Should be helpful anyway.

Mike

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Re: encoding latin1 to utf-8

2007-09-12 Thread Harshad Modi

thx for response ,
i think, my file has wrong encoding format.
thanks for guide and advise

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Re: Is the wxPython list down?

2007-09-12 Thread stef

[EMAIL PROTECTED] wrote:
 Hi,

 Does anyone know if the wxPython mailing list is having issues? I
   
Yes the server has hardware problems,
Robin Dunn (moderator), is informed about it.

cheers,
Stef Mientki
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Re: Is the wxPython list down?

2007-09-12 Thread Frank Millman

On Sep 12, 3:10 pm, [EMAIL PROTECTED] wrote:
 Hi,

 Does anyone know if the wxPython mailing list is having issues? I
 subscribe to it and haven't seen anything come through since
 09/06/2007. I went to ActiveState's archives and the last message
 there is from the 7th (http://aspn.activestate.com/ASPN/Mail/Browse/
 Threaded/wxPython-users).

 Thanks,

 Mike

This is from the wxPython home page -

(8-Sept-2007) Yes, the mail lists are down. There were multiple disk
failures in RAID5 array of the machine that hosts the mail lists. The
hardware has been replaced and data is being restored from tape
backups.

I noticed that cvs seems to be down as well - maybe it was on the same
server.

Frank

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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Dave Hansen

On Sep 12, 5:21 am, Charles Fox [EMAIL PROTECTED] wrote:
 I've just started playing around with Python, as a possible
 replacement for a mix of C++, Matlab and Lisp.  The language looks
 lovely and clean with one huge exception:  I do a lot of numerical
 modeling, so I deal with objects (like neurons) described
 mathematically in papers, by equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as far as I
 can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)
 For large equations this is going to make my code seriously unreadable
 to the point of needing to switch back to Matlab -- and it seems to go
 against everything else about python's simplicity and elegance.  Am I

It goes back to the Zen of Python (import this): Explicit is better
than implicit.  And it's a boon to future maintainers of your code

 missing something?  Is there something like a 'with' command that lets
 me set the scope, like

 with self:
   .a_dot = -.k(.a-.u)

The name self is just a convention.  You can give it any name you
wish.  Using s is common.

As others have mentioned, you can also provide local synonyms if the
dot syntax is too onerous.  But make sure you use the member access
syntax if the result of an expression is an immutable type.  For
example, I assume a_dot is a mutable type, such as a list.  If so,
then you could simply use

   a_dot, k, a, u = self.a_dot, self.k, self.a, self.u
   a_dot = -k(a-u)

However, if it's an immutable type, such as a scalar, strung, or
tuple, you need

   self.a_dot = -k(a-u)

And it gets trickier if you have members taking intermediate values...


 It's premature to make language suggestions as I am new to the

That's for sure  ;-)

Regards,

   -=Dave

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Re: library to launch program in linux

2007-09-12 Thread idzwan . nizam

On Sep 7, 2:49 am, Grant Edwards [EMAIL PROTECTED] wrote:
 On 2007-09-06, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:

  I'm a new user. What library should I use so that I canlaunch
 programin linux using python? Thank you in advance.

 subprocess

 --
 Grant Edwards   grante Yow! Hello, GORRY-O!!
   at   I'm a GENIUS from HARVARD!!
visi.com

can you please show me the sample code using subprocess library. I
would like user to have few option, program they could run. say,
firefox and x chat. thank you

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Re: pythonesque constructs for c++

2007-09-12 Thread Szabolcs Horvát

Josh wrote:
 One of the best features of python is its ease of use, and the ease of use 
 of its modules. Modules like os, os.path, and datetime are invaluable!
 
 Does anyone know of analagous c++ libraries? It seems to me that most of the 
 functionality of these modules could easily be replicated in c++. Before I 
 go about doing that, I was just wondering if anyone knows if they already 
 exist?

Check out Boost.

http://www.boost.org/
http://www.boost.org/libs/filesystem/doc/index.htm
http://www.boost.org/doc/html/date_time.html

-- 
Szabolcs
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Re: An ordered dictionary for the Python library?

2007-09-12 Thread Mark Summerfield

On 12 Sep, 13:46, Michele Simionato [EMAIL PROTECTED]
wrote:
 On Sep 12, 2:42 pm, Steven D'Aprano [EMAIL PROTECTED]

 cybersource.com.au wrote:
  On Wed, 12 Sep 2007 07:33:45 +, Mark Summerfield wrote:
  In fact, I'm not sure what people mean by ordered dicts. I assume they
  mean the keys are ordered, not the values. But ordered by what? Insertion
  order? Modification order? Alphabetical order?

 Insertion order.

  M.S.


Actually I meant by key order, so insertion order doesn't matter at
all. If you need a dictionary-like data structure that respects
insertion order you could use a list of (key, value) tuples.

Another respondent asked about use cases.

I have found time and again that I needed (key, value) pairs where the
key is some string that provides a representation for human readers
and the value is some internal key (e.g., database ID) that the system
uses internally. In these cases I often need to present the user with
a list of items from which to choose and want to present them in
sorted order. Naturally, I could use an ordinary dict and then do
this:

for string in sorted(d.keys()):
process(string)

But what happens when I need to do this a *lot* and when the number of
items is hundreds or a few thousands? I'm having to sort again and
again, since it is often the case that the items in the list changes
during the runtime of the application. So my solution in C++ is to use
an ordered dictionary (a map in C++ jargon), which in Python means I
can simply write:

for string in od.keys():
process(string)

Another situation where this is useful is if you need to hold lists of
strings preserving case but want them to be presented case-
insensitively. Here, you populate the ordered dictionary like this:

for string in somelist:
od[string.lower()] = string

Now you can iterate over od in case-insensitive order and yet still
have access to the case-sensitive original, and never have to
explicitly sort the strings.

I think it comes down to the nail and hammer issue: if you have a
hammer all problems look nail shaped. In Python we have dict and list
so everything looks suitable for those data structures. But having had
a wrench (ordered dictionaries) in C++, I find that some problems need
a wrench. I think that once Python programmers have access to an
ordered dictionary some proportion of them will find it painful to
program without it, so I really think it belongs in the standard
library.

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Re: Is the wxPython list down?

On Sep 12, 8:26 am, stef [EMAIL PROTECTED] wrote:
 [EMAIL PROTECTED] wrote:
  Hi,

  Does anyone know if the wxPython mailing list is having issues? I

 Yes the server has hardware problems,
 Robin Dunn (moderator), is informed about it.

 cheers,
 Stef Mientki

And to think, we're always told that that doesn't happen with RAID5.
Guess I should have checked the website. Thanks Stef and Frank.

Mike

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Re: An ordered dictionary for the Python library?

On Sep 12, 3:54 pm, Mark Summerfield [EMAIL PROTECTED]
wrote:
 On 12 Sep, 13:46, Michele Simionato [EMAIL PROTECTED]

 Actually I meant by key order, so insertion order doesn't matter at
 all. If you need a dictionary-like data structure that respects
 insertion order you could use a list of (key, value) tuples.

 Another respondent asked about use cases.

 I have found time and again that I needed (key, value) pairs where the
 key is some string that provides a representation for human readers
 and the value is some internal key (e.g., database ID) that the system
 uses internally. In these cases I often need to present the user with
 a list of items from which to choose and want to present them in
 sorted order. Naturally, I could use an ordinary dict and then do
 this:

 for string in sorted(d.keys()):
 process(string)

 But what happens when I need to do this a *lot* and when the number of
 items is hundreds or a few thousands? I'm having to sort again and
 again, since it is often the case that the items in the list changes
 during the runtime of the application. So my solution in C++ is to use
 an ordered dictionary (a map in C++ jargon), which in Python means I
 can simply write:

 for string in od.keys():
 process(string)


For your use case I would wrap a list [(key, value)] with a dict-like
object and I would use the bisect module in the standard library to
keep
the inner list ordered.

 M.S.

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Re: newbie: self.member syntax seems /really/ annoying

Dave Hansen a écrit :
(snip)
 As others have mentioned, you can also provide local synonyms if the
 dot syntax is too onerous.  But make sure you use the member access
 syntax if the result of an expression is an immutable type.  For
 example, I assume a_dot is a mutable type, such as a list.  If so,
 then you could simply use
 
a_dot, k, a, u = self.a_dot, self.k, self.a, self.u
a_dot = -k(a-u)
 
 However, if it's an immutable type, such as a scalar, strung, or
 tuple, you need
 
self.a_dot = -k(a-u)

Hmmm... Actually, whether self.a_dot is an instance of a mutable or 
immutable type won't change anything - in both case, it's only the 
*local* name a_dot that'll be rebound. So op as soon as you want to 
rebind (iow:assign to) an attribute, you *need* to use 
self.the_attr_name on the LHS.

Of course, *mutating* is a different situation...

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Re: An ordered dictionary for the Python library?

2007-09-12 Thread Duncan Booth

Steven D'Aprano [EMAIL PROTECTED] wrote:

 In fact, I'm not sure what people mean by ordered dicts. I assume they
 mean the keys are ordered, not the values. But ordered by what?
 Insertion order? Modification order? Alphabetical order? 

All of the above at different times. Usually I think they mean original 
insertion order, I'd more often like modification order though.

Insertion order can certainly be useful: any situation where you currently 
keep items in a list because the original order is important but also copy 
them into a dictionary or set because you need fast lookup. 
e.g. if you want only unique items out of a list but need to preserve order 
of first occurrence.

Another example would be uml-code round tripping: you parse in an existing 
file containing method definitions, then update the method definitions from 
a UML model and write the file out again: ArchGenXML does exactly that, but 
last I looked the methods were written out in whatever order the dictionary 
stored them which really messes up version control. It really should 
preserve the order that methods appeared in the file.

Modification order would be great for a cache. Touch items whenever they 
are referenced and then whenever the cache gets too big just pop the oldest 
until you get back to the desired size.

Alphabetical or other sorted order when you want to get smallest/largest or 
next smaller/larger then a specific item. I don't agree you necessarily 
mean ordered by key rather than value, I think you could specify any 
sortkey and expect updating the value to restore the ordering. Maybe if you 
are recording some stats and want to regularly output the top 10?
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Re: An ordered dictionary for the Python library?

2007-09-12 Thread Roel Schroeven

Michele Simionato schreef:
 On Sep 12, 2:42 pm, Steven D'Aprano [EMAIL PROTECTED]
 cybersource.com.au wrote:
 On Wed, 12 Sep 2007 07:33:45 +, Mark Summerfield wrote:
 In fact, I'm not sure what people mean by ordered dicts. I assume they
 mean the keys are ordered, not the values. But ordered by what? Insertion
 order? Modification order? Alphabetical order?
 
 Insertion order.

Mark referred to C++ and the sort function, so I assume he meant 
alphabetical order (or the equivalent for types other than strings).

-- 
If I have been able to see further, it was only because I stood
on the shoulders of giants.  -- Isaac Newton

Roel Schroeven
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Re: MemoryError on reading mbox file

2007-09-12 Thread Christoph Krammer

On 12 Sep., 12:20, David [EMAIL PROTECTED] wrote:
 It may be that Python's garbage collection isn't keeping up with your app.

 You could try periodically forcing it to run. eg:

 import gc
 gc.collect()

I tried this, but the problem is not solved. When invoking the garbage
collection after every loop run, the amount of memory indicated by top
stays the same for a very long time until at some point (at different
messages), while it is executing the loop header, the memory increases
until it hits 100% and swap hit also 100% = MemoryError

Can there be a problem within the mailbox module while processing too
large files?

Regards,
 Christoph


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Dynamically removing methods in new-style classes

2007-09-12 Thread agupta0318

I am trying unsuccessfully to remove some methods from an instance,
based on values passed in to the constructor as in the following
example:

#===
class A(object):

def __init__(self, id):
self._id = id
return

def clean(self):
if (self._id == 1):
del self.test1
elif (self._id == 2):
del self.test2
pass
return

def test1(self):
print in test1
return

def test2(self):
print in test2
return

#=
if (__name__ == '__main__'):
try:
a = A(1)
a.clean()
a.test2()
a.test1()
except AttributeError, exc:
import traceback
traceback.print_exc()
pass

#==
I get the following error:
Traceback (most recent call last):
  File DynamicMethods.py, line 30, in ?
a.clean()
  File DynamicMethods.py, line 11, in clean
del self.test1
AttributeError: test1

With the older python classes I could have done:
self.__class__.__dict__[''test1] to achieve the desired result.

I appreciate any help you could provide with this.

Thanks.

Amit Gupta

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Re: library to launch program in linux

2007-09-12 Thread Grant Edwards

On 2007-09-12, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:

 I'm a new user. What library should I use so that I canlaunch
 programin linux using python? Thank you in advance.

 can you please show me the sample code using subprocess library.

http://docs.python.org/lib/module-subprocess.html

 I would like user to have few option, program they could run.
 say, firefox and x chat.

I'd like to be 15 years younger.

-- 
Grant Edwards   grante Yow! I'm definitely not
  at   in Omaha!
   visi.com
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Re: MemoryError on reading mbox file

2007-09-12 Thread Hrvoje Niksic

Christoph Krammer [EMAIL PROTECTED] writes:

 I have to convert a huge mbox file (~1.5G) to MySQL.

Have you tried commenting out the MySQL portion of the code?  Does the
code then manage to finish processing the mailbox?
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Re: Dynamically removing methods in new-style classes

2007-09-12 Thread Hrvoje Niksic

[EMAIL PROTECTED] writes:

 I am trying unsuccessfully to remove some methods from an instance,

You can't remove the method from an instance because the method is
stored in its class.

 With the older python classes I could have done:
 self.__class__.__dict__[''test1] to achieve the desired result.

self.__class__.test1 still works, doesn't it?  Removing methods can be
achieved the same way:

 x=X()
 class X(object):
...  def blah(self): pass
...
 x=X()
 x.blah
bound method X.blah of __main__.X object at 0xb7d46bcc
 del type(x).blah
 x.blah
Traceback (most recent call last):
  File stdin, line 1, in module
AttributeError: 'X' object has no attribute 'blah'
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Re: Python Database Apps

2007-09-12 Thread [EMAIL PROTECTED]

On Sep 12, 8:39 am, Ed Leafe [EMAIL PROTECTED] wrote:
 On Sep 11, 2007, at 2:56 PM, [EMAIL PROTECTED] wrote:

  It's gonna be a desktop app.  The
  database engine is going to be the critical component.  I like sqlite
  so that I don't need a database server on the client side.  It would
  help though if there is a way to sync between multiple clients to a
  central server database.  That's the tough part.  To give you a better
  idea of what i'm trying to do, I am trying to write an app where
  multiple technicians have an issue tracker that is available both
  offline and online.  I was looking to use sqlite as the local side
  that would sync new and updated issues to a central server when
  online.  Any technician may work on any issue.  Generally they will
  not be working on the same issue at the same time.  The technicians
  are geographically diverse (anywhere in the southeast US, not in an
  office.)

 As far as the server goes, you can't go wrong with PostgreSQL, as
 others have mentioned. I have more experience with MySQL, but their
 recent licensing changes have simply made it easier to go with
 Postgres, as I don't have to worry about which clause of which
 document I might be violating.

 For the local data store, SQLite is far and away the best choice,
 since you don't have to use two types of data access, as you would if
 you went with SQL on the server and, say, pickling on the local.

 If you create both data stores with the same structure, you can use
 UUIDs as your keys, along with a timestamp flag for records that are
 added or modified when disconnected so that you can re-sync later.
 You will have to handle conflicts (i.e., someone changed a record
 that another also changed while disconnected) on your own,
 implementing your own business logic to determine who wins, and how
 the conflicted data is handled.

 I'll close with a plug for our product: Dabo. It is a desktop
 application framework with support for SQLite, PostgreSQL, MySQL,
 Firebird and Microsoft SQL Server databases. For disconnected data,
 you would simply define a local connection (to SQLite) and a remote
 connection (to your server database), and switch between the two
 depending on whether you are disconnected or not. The framework will
 handle the rest, allowing you to focus on the stuff that is unique to
 your app, such as the conflict resolution and business logic.

 -- Ed Leafe
 --http://leafe.com
 --http://dabodev.com

Thanks for ideas Ed.  I am checking out dabo now.  I do have a few
questions about it.  Packaging.  Is it easy to package into a quick
install for windows.  The users are going to want to get too in
depth.  Second, data sources.  When I'm adding a data source to the
window in class designer, it always picks up the one I created (which
incidentally was a sample, my form for connection manager isn't
working at the moment.)  My idea is to have the the local sqlite
database as the only viewable data source, and the server side only
for syncing.  So they logon, sync up, sync down, and view.  I'm
worried about having to get them to install python, dabo, and the app.

Darien

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Re: Dynamically removing methods in new-style classes

On Sep 12, 4:28 pm, [EMAIL PROTECTED] wrote:
 I am trying unsuccessfully to remove some methods from an instance,

Usuall one does not remove methods, but wraps the object and delegates
only to
a restricted number of methods. Is this solution viable? If not, you
may be
forced to change the class of the instance, or to play trick such as

def removed_method(self):
   raise NotImplementedError

self.test1 = removed_method.__get__(self)

  Michele Simionato

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RE: An ordered dictionary for the Python library?

2007-09-12 Thread Hamilton, William

 From: Michele Simionato
 
 On Sep 12, 3:54 pm, Mark Summerfield [EMAIL PROTECTED]
 wrote:
  On 12 Sep, 13:46, Michele Simionato [EMAIL PROTECTED]
 
  Actually I meant by key order, so insertion order doesn't matter at
  all. If you need a dictionary-like data structure that respects
  insertion order you could use a list of (key, value) tuples.
 
  Another respondent asked about use cases.
 
  I have found time and again that I needed (key, value) pairs where
the
  key is some string that provides a representation for human readers
  and the value is some internal key (e.g., database ID) that the
system
  uses internally. In these cases I often need to present the user
with
  a list of items from which to choose and want to present them in
  sorted order. Naturally, I could use an ordinary dict and then do
  this:
 
  for string in sorted(d.keys()):
  process(string)
 
  But what happens when I need to do this a *lot* and when the number
of
  items is hundreds or a few thousands? I'm having to sort again and
  again, since it is often the case that the items in the list changes
  during the runtime of the application. So my solution in C++ is to
use
  an ordered dictionary (a map in C++ jargon), which in Python means I
  can simply write:
 
  for string in od.keys():
  process(string)
 
 
 For your use case I would wrap a list [(key, value)] with a dict-like
 object and I would use the bisect module in the standard library to
 keep
 the inner list ordered.


Or subclass dict to carry along a sorted list of keys with it and return
that when dict.keys() is called.  Even better, only have .keys() sort
the keys list when a key has been added to it since the last call.


--
-Bill Hamilton
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Re: MemoryError on reading mbox file

2007-09-12 Thread Istvan Albert

On Sep 12, 5:27 am, Christoph Krammer [EMAIL PROTECTED]
wrote:

 string = self._file.read(stop - self._file.tell())
 MemoryError

This line reads an entire message into memory as a string. Is it
possible that you have a huge email in there (hundreds of MB) with
some attachment encoded as text?

Either way, the truth is that many modules in the standard library are
not well equipped to deal with large amounts of data. Many of them
were developed before gigabyte sized files were even possible to store
let alone process. Hopefully P3K will alleviate many of these problems
by its extensive use of generators.

For now I would recommend that you split your mbox file into several
smaller ones. (I think all you need is to split at the To: fields) and
run your script on these individual files.

i.








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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Charles Fox

Thanks guys -- yeah these two stategies (short s.varname; and explicit
rescoping, a=self.a etc) are more or less what I was using.  That's
still kind of annoying though.

The s.varname approach still makes numerical code much harder to read.

I had a nasty bug with the boilerplate approach when forgetting to
reassign some of the variables back to members (self.a=a).  And that's
a lot of boilerplate you need -- I thought the python way was to
minimize redundant code?  (Ditching header files and curley brackets
was a main reason for me coming here).

I see the argument for making self explicit -- what would be wrong
with just .a instead of self.a though?  That's still explicit but much
easier to read.  (I think I've seen that somewhere else, is it C#?)

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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Tim Golden

Charles Fox wrote:
Thanks guys -- yeah these two stategies (short s.varname; and explicit
rescoping, a=self.a etc) are more or less what I was using. That's
still kind of annoying though.

The s.varname approach still makes numerical code much harder to read.

I had a nasty bug with the boilerplate approach when forgetting to
reassign some of the variables back to members (self.a=a). And that's
a lot of boilerplate you need -- I thought the python way was to
minimize redundant code? (Ditching header files and curley brackets
was a main reason for me coming here).

I see the argument for making self explicit -- what would be wrong
with just .a instead of self.a though? That's still explicit but much
easier to read. (I think I've seen that somewhere else, is it C#?)

Charles, while you are quite right to air your ideas, do bear in mind
that this issue has been thrashed out again and again on this group
and in other forums. I hope you have at least read the FAQ:

http://www.python.org/doc/faq/general/#why-must-self-be-used-explicitly-in-method-definitions-and-calls

and PEP 3099:

http://www.python.org/dev/peps/pep-3099/

If you take the trouble to search the archives of this list alone
for, say, explicit+self, you'll see that there are quite strong arguments
(and argumentors) on both sides. In that sort of situation the status quo
tends to hold sway. (And in this case, GvR has only recently responded to
similar comments by Bruce Eckels -- a couple of heavyweights -- in a way
which makes it unlikely that this is going to change).

I think it's one of those things which comes down, fairly enough, to: we
do things this way and it works for us; other languages do other things
and it works for them.

TJG
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Re: Get Only the Last Items in a Traceback

2007-09-12 Thread [EMAIL PROTECTED]

On Sep 12, 5:17 am, Peter Otten [EMAIL PROTECTED] wrote:

 Your assessment is wrong. You only get the extra lines in the traceback if
 you don't immediately wrap the exec statement in a try ... except block:

 $ cat snip_traceback1.py
 import traceback

 def alpha():
 try:
 beta()
 except Exception, e:
 traceback.print_exc()

 def beta():
 gamma()

 def gamma():
 exec s in {}

 s = 
 def delta():
 epsilon()

 def epsilon():
 1/0
 delta()
 

 if __name__ == __main__:
 alpha()

 $ python snip_traceback1.py
 Traceback (most recent call last):
   File snip_traceback1.py, line 5, in alpha
 beta()
   File snip_traceback1.py, line 10, in beta
 gamma()
   File snip_traceback1.py, line 13, in gamma
 exec s in {}
   File string, line 7, in module
   File string, line 3, in delta
   File string, line 6, in epsilon
 ZeroDivisionError: integer division or modulo by zero

 So the first step is to move the try ... except closer to the exec:

 $ cat snip_traceback2.py
 import traceback

 def alpha():
 beta()

 def beta():
 gamma()

 def gamma():
 try:
 exec s in {}
 except Exception, e:
 traceback.print_exc()

 s = 
 def delta():
 epsilon()

 def epsilon():
 1/0
 delta()
 

 if __name__ == __main__:
 alpha()

 $ python snip_traceback2.py
 Traceback (most recent call last):
   File snip_traceback2.py, line 11, in gamma
 exec s in {}
   File string, line 7, in module
   File string, line 3, in delta
   File string, line 6, in epsilon
 ZeroDivisionError: integer division or modulo by zero

 You are almost there. Now let's strip off the outermost traceback:

 $ cat snip_traceback3.py
 import sys
 import traceback

 def alpha():
 beta()

 def beta():
 gamma()

 def gamma():
 try:
 exec s in {}
 except Exception, e:
 etype, value, tb = sys.exc_info()
 traceback.print_exception(etype, value, tb.tb_next)

 s = 
 def delta():
 epsilon()

 def epsilon():
 1/0
 delta()
 

 if __name__ == __main__:
 alpha()

 $ python snip_traceback3.py
 Traceback (most recent call last):
   File string, line 7, in module
   File string, line 3, in delta
   File string, line 6, in epsilon
 ZeroDivisionError: integer division or modulo by zero

 Heureka.

 Peter

Thanks for the help, Peter.  That's exactly what I need.  Now could I
use your tb.tb_next trick a couple times and thus avoid moving the try/
except?

-Greg

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Re: newbie: self.member syntax seems /really/ annoying

On Sep 12, 4:43 pm, Charles Fox [EMAIL PROTECTED] wrote:
 Thanks guys -- yeah these two stategies (short s.varname; and explicit
 rescoping, a=self.a etc) are more or less what I was using.  That's
 still kind of annoying though.

 The s.varname approach still makes numerical code much harder to read.

 I had a nasty bug with the boilerplate approach when forgetting to
 reassign some of the variables back to members (self.a=a).  And that's
 a lot of boilerplate you need -- I thought the python way was to
 minimize redundant code?  (Ditching header files and curley brackets
 was a main reason for me coming here).

You still can play with dictionaries, for instance:

def __init__(self, a, b, c):
   vars(self).update(locals())

correspond to

self.a = a
self.b = b
self.c = c

(and actually also to self.self =self).

 I see the argument for making self explicit -- what would be wrong
 with just .a instead of self.a though?  That's still explicit but much
 easier to read.  (I think I've seen that somewhere else, is it C#?)

This has been proposed many times. But self is handy because you can
give
a different name to it: for instance it becomes cls when you are
inside a classmethod.


Michele Simionato

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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Grant Edwards

On 2007-09-12, Tim Golden [EMAIL PROTECTED] wrote:

 I think it's one of those things which comes down, fairly
 enough, to: we do things this way and it works for us; other
 languages do other things and it works for them.

But not as nearly well as our way works for us, of course. ;)

-- 
Grant Edwards   grante Yow! I'm meditating on
  at   the FORMALDEHYDE and the
   visi.comASBESTOS leaking into my
   PERSONAL SPACE!!
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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread J. Clifford Dyer

On Wed, Sep 12, 2007 at 07:43:51AM -0700, Charles Fox wrote regarding Re: 
newbie: self.member syntax seems /really/ annoying:
 
 Thanks guys -- yeah these two stategies (short s.varname; and explicit
 rescoping, a=self.a etc) are more or less what I was using.  That's
 still kind of annoying though.
 
 The s.varname approach still makes numerical code much harder to read.
 

For what it's worth, if you stick with python for a while, you will stop 
noticing the self, and be able to see what you're looking for quite clearly.  

Moreso if you use s.

Cheers,
Cliff
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Re: Is the wxPython list down?

2007-09-12 Thread Chris Mellon

On 9/12/07, Frank Millman [EMAIL PROTECTED] wrote:
 On Sep 12, 3:10 pm, [EMAIL PROTECTED] wrote:
  Hi,
 
  Does anyone know if the wxPython mailing list is having issues? I
  subscribe to it and haven't seen anything come through since
  09/06/2007. I went to ActiveState's archives and the last message
  there is from the 7th (http://aspn.activestate.com/ASPN/Mail/Browse/
  Threaded/wxPython-users).
 
  Thanks,
 
  Mike

 This is from the wxPython home page -

 (8-Sept-2007) Yes, the mail lists are down. There were multiple disk
 failures in RAID5 array of the machine that hosts the mail lists. The
 hardware has been replaced and data is being restored from tape
 backups.

 I noticed that cvs seems to be down as well - maybe it was on the same
 server.


CVS is down because wx has moved to SVN, which is still up and running
fine. svn.wxwidgets.org.
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ANN: eGenix mxODBC and mxODBC Zope DA on 64-bit FreeBSD

2007-09-12 Thread eGenix Team: M.-A. Lemburg



ANNOUNCING

   eGenix.com mxODBC Database Interface

  eGenix.com mxODBC Zope Database Adapter

   for 64-bit FreeBSD


This announcement is also available on our web-site for online reading:
http://www.egenix.com/company/news/eGenix-mxODBC-on-FreeBSD-amd64-GA.html



eGenix mxODBC Distribution

The eGenix mxODBC Distribution is a Python database interface add-on
distribution for our eGenix mx Base Distribution. It comes with mxODBC,
our universal ODBC database interface for Python.

Customers who have purchased licenses for other platforms and wish to
move their installation to FreeBSD 64-bit, can do so without having to
buy a new license. The licenses will continue to work on the 64-bit
platform.

Users of mxODBC 2.0 will have to purchase new licenses from our online
shop in order to upgrade to mxODBC 3.0.

You can request 30-day evaluation licenses on the product page.

Downloads
-

Please visit the eGenix mxODBC Distribution page for downloads,
instructions on installation and documentation of the packages.

http://www.egenix.com/products/python/mxODBC/

Note that in order to use the eGenix mxODBC Distribution you need to
install the eGenix mx Base Distribution first.



eGenix mxODBC Zope DA


eGenix mxODBC Zope DA is our database interface for Zope and Plone. It
is based on the mxODBC interface.

Customers who have purchased licenses for other platforms and wish to
move their installation to FreeBSD 64-bit, can do so without having to
buy a new license. The licenses will continue to work on the 64-bit
platform.

You can request 30-day evaluation licenses on the product page.

Downloads
-

Please visit the eGenix mxODBC Zope DA product page for downloads,
instructions on installation and documentation of the packages.

http://www.egenix.com/products/zope/mxODBCZopeDA/



More Information

For more information on our products, licensing and download
instructions, please write to [EMAIL PROTECTED]

Enjoy,
-- 
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source  (#1, Sep 12 2007)
 Python/Zope Consulting and Support ...http://www.egenix.com/
 mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
 mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/

2007-08-22: Released mxODBC 3.0.1  http://python.egenix.com/

 Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! 


   eGenix.com Software, Skills and Services GmbH  Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
   Registered at Amtsgericht Duesseldorf: HRB 46611


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Re: newbie: self.member syntax seems /really/ annoying


Charles Fox wrote:
 I've just started playing around with Python, as a possible
 replacement for a mix of C++, Matlab and Lisp.  The language looks
 lovely and clean with one huge exception:  I do a lot of numerical
 modeling, so I deal with objects (like neurons) described
 mathematically in papers, by equations like
 a_dot = -k(a-u)
 In other languages, this translates nicely into code, but as far as I
 can tell, Python needs the ugly:
 self.a_dot = -self.k(self.a-self.u)
 For large equations this is going to make my code seriously unreadable
 to the point of needing to switch back to Matlab -- and it seems to go
 against everything else about python's simplicity and elegance.  Am I
 missing something?  Is there something like a 'with' command that lets
 me set the scope, like

 with self:
   .a_dot = -.k(.a-.u)

 It's premature to make language suggestions as I am new to the
 language, but I would have though that making a 'with self' explicit
 in all methods would have been neat, so I could just write
   .a_dot = -.k(.a-.u)
 which would still avoid confusion with local function variables, since
 '.a' is different from 'a'.

 Please help if I am missing something -- this looks like a great
 language but I am going to mad trying to read numerical code full of
 'self.'s breaking up the equations.

I don't know if it'll help or not, but you might try using matplotlib,
numpy or pymat. One of those may make it easier to do your
calculations.

Mike

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Re: Enum class with ToString functionality

2007-09-12 Thread Neil Cerutti

On 2007-09-11, Steven D'Aprano [EMAIL PROTECTED] wrote:
 Perhaps Ben should have followed the usual practice of
 commercial, closed- source software developers and started
 counting his version numbers at one instead of zero, miss a few
 releases, use randomly large increments occasionally, and ended
 up with a current version number of 2.7.1 for the exact same
 level of functionality.

 Or he could have called it Enum XP (for eXtra Programming
 perhaps) or Enum 2007. The next minor release could be Enum
 2008, and the next major update could be called Enum
 Professional Capowie!!!.

I like the (priviledged) code names adopted by the Linux
community for special versions, e.g., Enum 2.7.1 (Flapjacks).
This would really tie the Enum-using community together, and make
messages about it much cuter.

-- 
Neil Cerutti
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Re: National grid to lat long conversion

2007-09-12 Thread Astley Le Jasper

Hi,

I was a bit limited with time so in the end used an online service
with an API which is great for the limited number of look-ups I
needed. It can be found at:

http://www.nearby.org.uk/

It was also very useful for site for other conversions and lookups.

I manage to find a couple of other examples in other languages which I
might have used as the basis for some pythonification.

PHP
- http://www.megalithia.com/search/llfuncshighlight.php
- http://www.jstott.me.uk/phpcoord/

Javascript
- http://www.movable-type.co.uk/scripts/latlong-gridref.html

Cheers

Neil

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is it possible to use different font within one wxpython static text widget?

2007-09-12 Thread hyena

problem is as title, bear me if this too silly or too naive.

I use wx.statictext widget to show some information in GUI, there are some 
numbers in the text to be emphasized in bigger other color. For example, in 
sentence the travel speed of this car is 40 km /hour, I would like 40 to 
be bigger and in red color. I know I can use several statictext to get this 
effect. But i am quite relucktant to do so since I am quite unfamiliar with 
manageing the layout of widgets.

Is there a convinient way to have this done? Thanks for any .input



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Re: Python 3K or Python 2.9?

2007-09-12 Thread Alex Martelli

Duncan Booth [EMAIL PROTECTED] wrote:
   ...
 As for omitting 'self' from method definitions, at first site you might
 think the compiler could just decide that any 'def' directly inside a
 class could silently insert 'self' as an additional argument. This 
 doesn't work though because not everything defined in a class has to be
 an instance method: static methods don't have a self parameter at all,
 class methods traditionally use 'cls' instead of 'self' as the name of
 the first parameter and it is also possible to define a function inside
 a class block and use it as a function. e.g.

Actually you could do the magic first-parameter insertion just when
returning a bound or unbound method object in the function's __get__
special method, and that would cover all of the technical issues you
raise.  E.g.:

 class Weird:
def factory(arg):
Returns a function based on its argument
 
foo = factory(foo)
bar = factory(bar)
del factory
 
 When factory is called, it is a simple function not a method. If it had

Sure, that's because the function object itself is called, not a bound
or unbound method object -- indeed. factory.__get__ never gets called
here.

 class C:
def method(self): pass
 
 and
 
 def foo(self): pass
 class C: pass
 C.method = foo
 
 both of these result in effectively the same class (although the second
 one has a different name for the method in tracebacks).

And exactly the same would occur if the self argument was omitted from
the signature and magically inserted when __get__ does its job.

 That consistency really is important. Whenever I see a 'def' I know 
 exactly what parameters the resulting function will take regardless of
 the context.

And this non-strictly-technical issue is the only true one.

 Another area to consider is what happens when I do:
 
 foo = FooClass()
 
 foo.bar(x)
 # versus
 f = foo.bar
 f(x)
 
 Both of these work in exactly the same way in Python: the self parameter

And so they would with the __get__ does magic rule, NP.

 My point here is that in Python the magic is clearly defined and 
 overridable (so we can have static or class methods that act 
 differently).

And so it would be with that rule, since staticmethod c create
different descriptor objects.

Really, the one and only true issue is that the Python community doesn't
like magic.  It would be perfectly feasible, we just don't wanna:-).


Alex
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Re: newbie: self.member syntax seems /really/ annoying

2007-09-12 Thread Chris Mellon

On 9/12/07, Charles Fox [EMAIL PROTECTED] wrote:
 Thanks guys -- yeah these two stategies (short s.varname; and explicit
 rescoping, a=self.a etc) are more or less what I was using.  That's
 still kind of annoying though.

 The s.varname approach still makes numerical code much harder to read.

 I had a nasty bug with the boilerplate approach when forgetting to
 reassign some of the variables back to members (self.a=a).  And that's
 a lot of boilerplate you need -- I thought the python way was to
 minimize redundant code?  (Ditching header files and curley brackets
 was a main reason for me coming here).

 I see the argument for making self explicit -- what would be wrong
 with just .a instead of self.a though?  That's still explicit but much
 easier to read.  (I think I've seen that somewhere else, is it C#?)

 --
 http://mail.python.org/mailman/listinfo/python-list



This is terrible and horrible, please don't use it. That said,
presenting the magic implicit_self context manager!

from __future__ import with_statement
import sys

class implicit_self(object):
def __init__(self, obj):
self.obj = obj
def __enter__(self):
local = sys._getframe(1).f_locals
local.update(self.obj.__dict__)
def __exit__(self, exc, obj, tb):
local = sys._getframe(1).f_locals
for k in self.obj.__dict__:
setattr(self.obj, k, local[k])

if __name__ == '__main__':
class Test(object):
pass
t = Test()
t.a = 10
t.b = 20
with implicit_self(t):
print a
print b
a = 40
b = a * 2

print t.a
print t.b
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Re: Get Only the Last Items in a Traceback