different behaviour for user defined exception with attribute args

2009-09-29 Thread Visco Shaun
Hi all

For an exception defined as below

class OptionError(Exception):
def __init__(self, args):
self.args = args
def __str__(self):
return repr(self.v)

an iteration is happening when the exception is raised

Meanwhile for almost the same structured exception replacing the
attribute 'args' with say 'value' it is not a probs.

class OptionError(Exception):
def __init__(self, args):
self.value = args
def __str__(self):
return repr(self.value)

This was frustrating because for a st. OptionError('Error') for
exception 1 output will be

OptionError: ('E', 'r', 'r', 'o', 'r') 

Meanwhile for exception 2 output will be 

OptionError: 'Error'

which is desired..Why this behaviour?

Regards
Visco

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TypeError: 'int' object is not callable

2009-06-01 Thread Visco Shaun
when I was executing the below code I got TypeError: 'int' object is
not callable exception. Why is it so?

if type(c) == type(ERROR):

c can be a string or an integer representing an error
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visco

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Any adv. in importing a module and some objects in the same module, into the same file?

2009-04-18 Thread Visco Shaun
http://docs.python.org/library/logging.html

While going thr' the above link i came across import statements 
import logging
import logging.handlers

What is the use of second import as the first import will be
enough(AFAIK) to access anything intended by the second import?
Is there any kind of advantage?
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Thanks  Regards
visco

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how to know the importing file name from an imported file?

2009-04-17 Thread Visco Shaun
Hi

Is there a way to know the name of the script(say A), which is importing
a module(say B), from B?
ie in above situation i should be able to get name 'A' through some way
in B, when A contains an 'import B' statement.
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visco

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to get name of file opened

2009-03-28 Thread Visco Shaun
Hi

Is there any way to get the name of the file opened from the file object
'f' which i get through the code 

f = os.fdopen(os.open(trial', os.O_WRONLY|os.O_CREAT), w)

The situation will be like i can access only the above variable 'f'.
f.name is having 'fdopen' instead of filename 'trial'

Or if not possible can anyone suggest a solution where my requirements
are
a) i need file access through os module
b) i need file object and not file descriptor as its more easy to use

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visco

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difference between os.fdopen and builtin open

2009-03-28 Thread Visco Shaun
Hi

I was wondering the difference between os.fdopen()(or os.open() not
considering the difference in args) and builtin open(). Can anyone help
me?
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visco

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Re: to get name of file opened

2009-03-28 Thread Visco Shaun
First of all
Thanks Dave for the reply
On Sat, 2009-03-28 at 09:51 -0500, Dave Angel wrote:
 First question is why you need os.open(), and not the open() function.  
 I'll guess that you need some of the access modes (e.g. for file 
 sharing) that you get from the low level functions.  So assuming that:
of course access was an issue.. but i opted for it because in the
document it is mentioned that os.open(besides sharing b/w processes) is
low level resembling unix system call, and i thought may be efficiency
is more, even though interpreted by the same python interpreter...
But i never found any article regarding any efficiency difference
between those..
Can u comment on this
 I don't believe there's any way to use a fd (file descriptor) to 
 retrieve the file name that was perhaps passed to open.  There are ways 
 to spelunk inside Windows, but they're not advisable. And I don't know 
 what Unix might offer there.
 
 So by the time fdopen() is invoked, the name is already gone.
 
 Here's what I'd do.  Create your own open function that has the 
 parameters of os.open(), but that will return an object derived from the 
 file object.  Your derived object can have its own filename, but close() 
 will know what to do.
Well this is what i am trying now, though i wished if there was any
suitable method or attribute built within python
 
 Alternatively, you could encapsulate the line you showed, and just zap 
 the name attribute of the existing file object.right when it's being 
 returned by fdopen()
The name attribute appears to be read only as i tried that already
though through the interpreter rather than in code


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subprocess module: execution of standard binaries without shell?

2009-02-26 Thread Visco Shaun
hi all

while getting used to with subprocess module i failed in executuing a)
but succeeded in running b). Can anyone explain me why as i am providing
absolute path? Is this has to do anything with shared library.. which
must be accessed based on system variables?


a) pipe = subprocess.Popen(/bin/ls /, stdout=subprocess.PIPE,
close_fds=True)
==OSError: [Errno 2] No such file or directory

b) pipe = subprocess.Popen(/bin/ls /, stdout=subprocess.PIPE,
close_fds=True, shell=True)

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visco

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