[Tutor] incomprehension in type of classes.
hello, I have 2 questions. the first one is maybe not directly related to python (it's about eric3), and the second oneis about what the command `type' give back for two instances in my python code I have changed some classes like the following from (I): class CYear: def __init__(self, year): self.__year=year print str(self.__year) <<---(*) print 'dir of: '+str(dir(self)) print 'type of: '+str(type(self)) def __str__(self): return "we are in "+str(self.year) to (IIOB): class CYearDerived(int): def __init__(self, year): super(CYearDerived,self).__init__(year) self.__year=year print str(self.__year)<<-(*OB) print 'dir of: '+str( dir(self) ) print 'type of: '+str(type(self)) def __str__(self): return "we are in "+super(CYearDerived,self).__str__() Question 1 (about eric3) -- with the change from I to II, when I debug the code, I don't see the self arborescence (that you find in Window Debug Browser>>Local Variables) which shows you the attributes of the class that you are currently debugging in. Quesion 2 ----- why type of (CYear(2005)) and type(CYearDerived) doesn't give the same type ??? -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] incomprehension in type of classes.
> >from (I): > > > >class CYear: > > def __init__(self, year): > > self.__year=year > > print str(self.__year) <<---(*) > > print 'dir of: '+str(dir(self)) > > print 'type of: '+str(type(self)) > > def __str__(self): > > return "we are in "+str(self.year) > > > > > >to (IIOB): > > > >class CYearDerived(int): > > def __init__(self, year): > > super(CYearDerived,self).__init__(year) > > self.__year=year > > print str(self.__year)<<-(*OB) > > print 'dir of: '+str( dir(self) ) > > print 'type of: '+str(type(self)) > > def __str__(self): > > return "we are in "+super(CYearDerived,self).__str__() > > >why type of (CYear(2005)) > > > > > >and type(CYearDerived) > > > > > >doesn't give the same type ??? > > It's a difference between new-style and old-style classes. CYear is an > old-style class because it doesn't inherit from object. CYearDerived is a > new-style class because it inherits from int which is a subtype of object: > > >>> class C: pass # old-style class > ... > >>> type(C()) > > >>> C().__class__ > > > >>> class C2(object): pass # new-style class > ... > >>> type(C2()) > > >>> C2().__class__ > > > >>> int.__bases__ # int inherits from object > (,) > > I'm not sure *why* there is this difference between the two types of > classes, but there is... ah... I din't know that there was two kinds of classes. So you mean that, now the new style object should be like: class A(object): pass >>> class A: pass ... >>> class B(object): pass ... >>> a=A() >>> b=B() I see that dir (b) compare to dir(a) provides more stuff. So the new style of a class, is not only about syntax but also about properties ??? ok, I'll try to find more about this ! > By the way extending int does not work the way you have done it here. int > is an immutable type so you have to initialize it in the __new__() method, > not in __init__(). Read the details here: > http://www.python.org/2.2/descrintro.html#__new__ this link is very usefull thanks Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] creation of a module
hi,
1)
I'm trying to create my _first_ own module. I've decided to write each class
into a separate file.
/MyModule|-bunch.py
|-a.py
|-b.py
`-c.py
{a,b,c}.py contains respecetively classA,classB,classC more some unittest
and bunch.py will contains some usefull function using the class{A,B,C}
I'd like that when I import MyModule (`import MyModule')OB
I'll see from it:
MyModule.classA
.classB
.classC
.
.
...
without seeing MyModule.{a,b,c}
2) does someone now how to do this:
x=3
with a function like:
assign('x',3)
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Re: [Tutor] creation of a module
> > hi,
> >
> > 1)
> > I'm trying to create my _first_ own module. I've decided to write each
> > class into a separate file.
OB> >
> > /MyModule|-bunch.py
> > |-a.py
> > |-b.py
> > `-c.py
>
> You also need MyModule/__init__.py to signal to Python that MymModule is a
> package. (Actually you
> are creating a package containing several modules.)
thank you to enlight me.. :).. that I was creating a package containing many
modules. Maybe I'm smarter than I thought.
> > {a,b,c}.py contains respecetively classA,classB,classC more some unittest
> > and bunch.py will contains some usefull function using the class{A,B,C}
> >
> > I'd like that when I import MyModule (`import MyModule')OB
> > I'll see from it:
> > MyModule.classA
> > .classB
> > .classC
> > .
> > .
> > ...
> > without seeing MyModule.{a,b,c}
>
> In MyModule/__init__.py put
> from MyModule.a import classA
> from MyModule.b import classB
> from MyModule.c import classC
I've done it. But is it normal that I'see also the filename
MyModule.classA
.classB
.classC
.a < not expected
.b <--'
.c <-'
.
.
can I not import them ?
> This creates package-level attributes for the classes.
>
> > 2) does someone now how to do this:
> > x=3
> > with a function like:
> > assign('x',3)
>
> Can you say why you want to do this? It is possible but generally it is
> better to use a dict:
> values = {}
> values['x'] = 3
>
the idea was to automate the :
from MyModule.a import classA
from MyModule.b import classB
from MyModule.c import classC
with a loop
lclassname=['classA', 'classB', 'classC']
#in the future I can even automate the creation of classname list
for classname in lclassname:
#filename='a', classname='classA'
filename=classname.replace('class','').lower()
#from filename import classname
#can't do this
module=__import__(filename, gloabls(), locals(), [classname])
classDefinition=getattr(module,classname)
assign(classname,classDefinition)
In this way, when I'll do an
import FWobs
I'll get:
MyModule.classA
.classB
.classC
.
.
thanks for your help !
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Re: [Tutor] creation of a module
Hi Alan
> Hi Cedric,
>
> Reading through this I can't help but think you are going to
> a lot of trouble to make things very complicated for yourself
> - and for anyone else who has to work on your code. The
> Python module system is very simple and helpful in tracking
> down where the various things live. You can see by the
> prefix name which package/file provides which service.
> It appears that you are trying to hide that information?
>
> Is there a special reason why you are trying to introduce
> this kind of obfuscation?
>
> > > > {a,b,c}.py contains respecetively classA,classB,classC more some
> unittest
> > > > and bunch.py will contains some usefull function using the
> class{A,B,C}
> > > >
> > > > I'd like that when I import MyModule (`import MyModule')OB
> > > > I'll see from it:
> > > > MyModule.classA
> > > > .classB
> > > > .classC
> > > > .
> > > > .
> > > > ...
> > > > without seeing MyModule.{a,b,c}
>
> Why do you want to conceal the information about what lives inside
> the package? How will users be able to debug the package? If you
> hide a,b and c you will make it harder to do things like
I thought that it will be more convenient. But as I can read from your email:
it seems a really __not_so_good__ idea .
>
> >>> dir(MyModule)
> >>> dir (MyModule.a)
>
> etc to explore the structure and find the code.
never done such kind of things.
>
> > I've done it. But is it normal that I'see also the filename
>
> Actually you don;t see the filename you see the sub moduile names.
> a.py becomes a module called a within your package.
>
> > the idea was to automate the :
> > from MyModule.a import classA
> > from MyModule.b import classB
> > from MyModule.c import classC
>
> What is the advantage - apart from a minimal amount of typing?
> You still need to maintain a list of the class/module mappings.
no the idea was to give a prefix to all my files depending on the way I'd like
to import them. In fact, my files are named class_foo.py and the class inside
this file is named CFoo.
> > with a loop
> >
> > lclassname=['classA', 'classB', 'classC']
> > #in the future I can even automate the creation of classname list
> > for classname in lclassname:
> > #filename='a', classname='classA'
> > filename=classname.replace('class','').lower()
>
> Maybe you should use a dictionary as Kent suggested:
>
> classes = {'classA': 'a',
>'classB': 'b',
>'classC : 'c'
> }
>
> filename = classes[classname]
>
> > #from filename import classname
> > module=__import__(filename, gloabls(), locals(), [classname])
> > classDefinition=getattr(module,classname)
> > assign(classname,classDefinition)
> >
>
> But this is a lot of work to sabve a very small amount of typing and
> could slow down your program initialisation significantly.
>
> > In this way, when I'll do an
> > import FWobs
> > I'll get:
> > MyModule.classA
> > .classB
> > .classC
> > .
> > .
>
> It looks as if all you really want to do is avoid having the
> sub-module names visible when you import the package. As I
> explained above I think thats a fundamentally bad idea.
Good, I'll follow your recommendation
> If you do just want to export a single set of services from a
> single import it would be much simpler to just put them all
> in a single module! And then you can hide the exposed names
> using the Python naming convention of prefixing with '_'
> or ' __'.
>
> Of course if its a very large set of services a package
> is better, but then you probably should expose the sub modules
> too. NAmespaces are one of Pythons best features - they are
> simple to use and very effective both in controlling program
> structure and in aiding debugging, its probabnly best to use
> them as intended rather than trying to force them to work
> differently.
>
> All IMHO of course! :-)
>
> Alan G
thanks for your time.
Ced.
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Re: [Tutor] Testing for commandline args
> Also, I hear that optparse is much better than getopt. this is a true pleasure to work with optparse. It was included in python2.3 and was primarly called python-optik Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for HOWTO's
Maybe this is Off-Topic but I found recently a perfect repository of python tutorials at: http://www.awaretek.com/tutorials.html Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] interactif or not
hi, How can I know if a script is launched interactively or not because I'd like to make a script verbose or not depending if it is executed as interactive or not. eg. If I invoke it in a shell.. then it can be verbose If it is launched from a crontab.. then it is less verbose. Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] interactif or not
> If you want to know if your program has been launched from an interactive > terminal or from a system background process like cron or init, then you > look to see if stdin is a tty. Unix is usually very careful about who has a > "controlling tty" and who does not. In Python, file objects have an isatty() > method that will return True or False. > > import sys > isinteractive = sys.stdin.isatty() > if isinteractive: > ... > else: > ... > tested and it works ! Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] python and database
Hi, I've read this: http://www.python.org/workshops/1997-10/proceedings/shprentz.html and some points look good: - no hand coded SQL queries - provide a cache - objects insert and updates - ... but quite old too. So the question is : what are the best practice to use python with a pgsql. Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] module with static global
give an eyes to sqlobject.org. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] SQL headache with column
did you heard about sqlobject ? give a try...http://www.sqlobject.org/ Ced. -- Cedric BRINER ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] python learning
hi,
1)OB
I'm learning for almost a year and half python. this is my first language. I'm
fine with classes, definition... But now I'm trying to understand better things
as:
static method
class method
and the use of metaclass.
Does some one of you knows about a compilations of small snippets showing how
things works!
an url ?
because I'm trying to work with sqlobject, and I have to tell my self that I'm
far away of a good comprehension of it.. : (
2)
Sometimes, I do think that it will help a lot, to have such compilations. So
that people can scan it, test them very easily. Such snippet shall have some
use of them (case that work, case that do not work) some explanation in which
can we can use them and so on.
For example, what I've learned recently.
module.py
class test(object):
def __init__(self):
self.dico={}
def setname(self,name, value):
self.dico[name]=value
def dico(self):
return printDico
testInstance=test()# *
setname=testInstance.setname # **
dico=testInstance.dico # ***
in the python interpreter.
import module
module.setname('key1','value1')
module.dico()
del module
# so I've supposed that the garbage collector will destruct this.
from module import dico
dico()
# tintintammm and badaboum there are still there
So I imagine, that when you import this module. ``testInstance'' is created
in the object space, but it is not assigned to the namespace. So the only way to
destruct such module, will be within the module.
I found that such module act has a singleton
Ced.
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Re: [Tutor] Basic class inheritance
> > However, is it possible to achieve this without rewrite the whole
> > __init__ method, but just overriding parts of it?
>
> The usual way to do this is to forward to the __init__() method of the
> superclass for the common part. In your case you are just specializing the
> default arguments so all you have to do is pass the args to A.__init__():
>
> class B(A):
> def __init__(self, blank=True, editable=True, name='foo'):
> A.__init__(self, blank, editable, name)
>
I thought such kind of thing should be writted like:
class A(object):
def __init__(self, blank=False, editable=True, name='foo'):
self.blank = blank
self.editable = editable
self.name = name
class B(A):
def __init__(self, blank=True, editable=True, name='foo'):
super(B, self).__init__(blank, editable, name)
Ced.
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[Tutor] uncomprehension on RE
Hello,
I do not understand the behaviour of this:
import re
re.search('(a)*','aaa').groups()
('a',)
I was thinking that the ``*'' will operate on the group delimited by the
parenthesis. And so, I was expecting this result:
('a', 'a', 'a')
Is there something I'am missing ?
Ced.
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Re: [Tutor] uncomprehension on RE
Kent Johnson wrote:
> cedric briner wrote:
>> Hello,
>>
>> I do not understand the behaviour of this:
>>
>> import re
>> re.search('(a)*','aaa').groups()
>> ('a',)
>>
>> I was thinking that the ``*'' will operate on the group delimited by the
>> parenthesis. And so, I was expecting this result:
>> ('a', 'a', 'a')
>>
>> Is there something I'am missing ?
>
> It just doesn't work that way.
that's sad :(
> The returned group is the last string
> matched by the group:
> In [17]: re.search('(a.)*','azabac').groups()
> Out[17]: ('ac',)
Somewhere I find re really too difficult. I was never able to write an
re expression rightly from the first shoot ! Happily there is kodos and
redet.
> Use re.findall() instead:
> In [18]: re.findall('a.', 'azabac')
> Out[18]: ['az', 'ab', 'ac']
that's what I found, that I've to do the job with many python steps than
just one
> If you want overlapping matches you have to search in a loop and collect
> them yourself, findall() gives only non-overlapping matches.
To let you know, I'm writing a script to generate bind9 configuration
from a nis hosts table. So I was trying in a one re to catch from this:
[ ...] [# comment]
e.g:
10.12.23.45 hostname1 alias1 alias2 alias3 # there is a nice comment
37.64.86.23 hostname2
35.25.89.34 hostname3 alias5
.. ..
so I was wishing to write an re expresion which will do in a one step
all the job ! maybe am'I expecting too much from re :)
Ced.
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Re: [Tutor] uncomprehension on RE
Kent Johnson wrote: > cedric briner wrote: >> To let you know, I'm writing a script to generate bind9 configuration >> from a nis hosts table. So I was trying in a one re to catch from this: >> >> [ ...] [# comment] >> e.g: >> 10.12.23.45 hostname1 alias1 alias2 alias3 # there is a nice comment >> 37.64.86.23 hostname2 >> 35.25.89.34 hostname3 alias5 >> .. .. >> >> >> so I was wishing to write an re expresion which will do in a one step >> all the job ! maybe am'I expecting too much from re :) > > You can use an re to get the four primary fields, then use split() to > break up the aliases. Try this: > > import re > data = '''10.12.23.45 hostname1 alias1 alias2 alias3 # there is a nice > comment > 37.64.86.23 hostname2 > 35.25.89.34 hostname3 alias5 > '''.splitlines() > > for line in data: > match = re.search(r'^(\S+)\s+(\S+)([^#]*)(#.*)?$', line) > if match: > ip, host, aliases, comment = match.group(1, 2, 3, 4) > print 'ip:', ip > print 'host:', host > if aliases: > aliases = aliases.strip().split() > for alias in aliases: > print 'alias:', alias > if comment: > print comment > print I had done that before writing my first email. I knew how to do this in few python steps. But some how I was expecting RE beeing able to do this in an one shoot. Thanks for your precious help. Ced. > > Kent > -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] uncomprehension on RE
Stephen Nelson-Smith wrote: > On 9/20/07, cedric briner <[EMAIL PROTECTED]> wrote: > >> To let you know, I'm writing a script to generate bind9 configuration >> from a nis hosts table. So I was trying in a one re to catch from this: >> >> [ ...] [# comment] >> e.g: >> 10.12.23.45 hostname1 alias1 alias2 alias3 # there is a nice comment >> 37.64.86.23 hostname2 >> 35.25.89.34 hostname3 alias5 > > I'm not sure I follow. Could you state explicitly what the input is > (I think the above), and what output you want? > > S. > the input is 10.12.23.45 hostname1 alias1 alias2 alias3 # there is a nice comment 37.64.86.23 hostname2 35.25.89.34 hostname3 alias5 the ouput is [ ...] [# ] -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] tree/node class/module
hello, I'm wanting to do a GUI for to help people using rsync, du, tar . it will provide the --exclude and --include of them. And I thought that the best way to store data relative to the hierarchy filesystem was to store them in a tree structure. But after browsing ages on the web, I didn't found any class/modules which implements trees, with some comments, and small examples. Am I just blind ??? I'm looking for a tree of object which will give me stuff like: - sibling - parent - children - find - insert Do you have any pointers ?? Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] tree/node class/module
usefull page > http://www.velocityreviews.com/forums/t355467-tree-and-graph-structures-in-python.html > thanks again Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] IDEs
what about eric3 ? http://www.die-offenbachs.de/detlev/eric3.html Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python DB
I love sqlobject.org it this a wrapper between many sql implementation (mysql, postgresql..) and python. get a look. Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] cas and python
hi, does one of you knows if there is a python module which implements CAS(Central Authentication Service): https://clearinghouse.ja-sig.org/wiki/display/CAS/Home thanks in advance Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] ldap client
debian/sarge hello, I'm wanting to interogate an ldap server to fetch informations. so I'm looking for a python2.4 ldap client. And the only I've found is python2.4-ldaptor. Does some of you knows an good ldap client which use SSL ? Ced. -- Cedric BRINER Geneva - Switzerland ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
