Changing the private variables content

[Ryniek90]

>
> ------------------------------------------------------------------------
>
> Temat:
> Re: Changing the private variables content
> Od:
> Gary Herron <gherron at islandtraining.com>
> Data:
> Tue, 21 Jul 2009 14:14:44 -0700
> Do:
> Ryniek90 <ryniek90 at gmail.com>
>
> Do:
> Ryniek90 <ryniek90 at gmail.com>
> Kopia:
> python-list at python.org
>
>
> Ryniek90 wrote:
>> Hi.
>> I'm writing some class, and decided to use inside private method and 
>> some private variables. While with method i haven't got any problem's 
>> with variables i have.
>> Maybe some example.
>> A class with private method and private variable:
>>
>> "
>> >>> class Secret(object):
>>    #
>>    def __init__(self):
>>        self._number = 1
>>    #
>>    def _secret(self):
>>        print self._number
>>    def showit(self):
>>        print "Secret number is:\n"
>>        self._secret()
>>
>> >>> sec = Secret()
>> >>> sec.showit()
>> Secret number is:
>>
>> 1
>> >>> sec._number
>> 1
>> >>> sec._number = 2
>> >>> sec._number
>> 2
>> >>> sec._number += 3
>> >>> sec._number
>> 5
>> >>>
>> "
>>
>> As You can see, i made class with private method and private variable 
>> inside __init__ constructor. I've changed also the variable value, 
>> but outside class.
>> I've got problem with changing some variable value _inside__my_ 
>> class, which i'm writing.
>
> Not sure this is what you are asking, but a method (which is how I 
> interpret "_inside__my_ class") changes the value by normal assignment 
> like this:
>
> class Secret(object):
>  ...
>  def SetNumber(self,value):
>    self._number = value
>
> Is that what you were asking?
>
>
> Gary Herron
>
>
>
>> I've searched over google, some tuts with topics about operations on 
>> private variables, but didn't found anything - only how to make them, 
>> but no how to assign new objects/override them with new content (and 
>> other advanced and helpful options).
>>
>> If someone could help me, it would be great.
>>
>> Thanks.
>
>


Thanks for hint, but looks like i can't do what i want.

Maybe i show You my class:

"

class ModPrint(object):
   
    u"""
    This will be the doc.
    """
   
    def __init__(self):
       
        #Assign the Python installation directory - sys.exec_prefix - to 
variable
        self._default_search_path=sys.exec_prefix
        self._chosen_module = ''
        self._user_search_path = ''
        self._this_module = ''
       
    def _SetVar(self, attr, val):
        self.attr = val   
       
    def _search_for_module(self, *args):
       
        """Private method which walks through default Python 
installation directories, and search for prefered module."""
       
        #walking thru all directories available in path '_user_search_path'
        for root, dirs, files in os.walk(self._user_search_path):
            for f in files:
               
                #if found file 'f' is THAT module,
                #full path to THAT file is assigned to variable
                if f == ("%s.py" % self._chosen_module):
                    self._SetVar(self._this_module, os.path.join(root, f))
                   
                   
    def print_module(self, _chosen_module='', _user_search_path='', 
_default_search_path=sys.exec_prefix,):
       
        """Reads module chosen by user, and returns full content of this 
module, as it is."""
       
       
        #if custom search path hasn't been assigned,
        #default path is being assigned as custom path
        if self._user_search_path == '':
            self._user_search_path = self._default_search_path
           
        #using private method '_search_for_module' with 'self.' preffix
        #to search for prefered module
        self._search_for_module(_chosen_module, _user_search_path)
       
        #opening prefered module with read-only binary mode
        #and assigning it to 'module_open' variable
        module_open = open(self._this_module, 'rb')
       
        #reading this file and assigning it to variable
        module_text = module_open.read()
       
        #closing read file; the read content is still available
        #it's stored in variable 'module_text'
        module_open.close()
       
        #returning the read content
        return module_text

"

When i use this class in Python IDLE, i've got this error:
"
 >>> mod = ModPrint()
 >>> import socket
 >>> mod.print_module('socket')

Traceback (most recent call last):
  File "<pyshell#60>", line 1, in <module>
    mod.print_module('socket')
  File "<pyshell#57>", line 48, in print_module
    module_open = open(self._this_module, 'rb')
IOError: [Errno 2] No such file or directory: ''
 >>>
"

As You can see, i can't assign the new value "os.path.join(root, f)" to 
the 'self._this_module variable'.
So for sure i've made some mistake in method:

"
def _SetVar(self, attr, val):
        self.attr = val   
"
When i've changed private variables to normal, stored in class (in 
__init__ method), it was the same situation - i couldn't change this 
variable value.

"
 >>> mod = ModPrint()
 >>> mod.print_module('os')

Traceback (most recent call last):
  File "<pyshell#72>", line 1, in <module>
    mod.print_module('os')
  File "<pyshell#64>", line 48, in print_module
    module_open = open(self.this_module, 'rb')
IOError: [Errno 2] No such file or directory: ''
 >>>
"

Thanks i someone could help me, give some hint.