extend getattr()

[Rotlaus]

Hello,

lets assume i have some classes:

class A(object):
def __init__(self):
b = B()

class B(object):
def __init__(self):
c = C()

class C(object):
def __init__(self):
pass

and now i wanna do something like this:

a=A()
c=getattr(a, 'b.c')

I know this doesn't work, but what can i do to get this or a similar
functionality to get it work for this sample and for even more nested
classes?

Kind regards,

Andre

[=?ISO-8859-1?Q?Gerhard_H=E4ring?=]

Re: extend getattr()

Rotlaus wrote:

Hello,
>
lets assume i have some classes:
[...]
>
a=A()
c=getattr(a, 'b.c')
>
I know this doesn't work, but what can i do to get this or a similar
functionality to get it work for this sample and for even more nested
classes?

Just recursively apply the getattr(), like this:

class A(object):
def __init__(self):
self.b = B()

class B(object):
def __init__(self):
self.c = C()

class C(object):
def __init__(self):
pass

def ext_getattr(obj , attr):
for subattr in attr.split(".") :
obj = getattr(obj, subattr)
return obj

a=A()
c = ext_getattr(a, 'b.c')

-- Gerhard

[=?iso-8859-1?q?C=E9dric_Lucantis?=]

Re: extend getattr()

Le Thursday 26 June 2008 13:06:53 Rotlaus, vous avez écrit :

Hello,
>
lets assume i have some classes:
>
class A(object):
def __init__(self):
b = B()
>
class B(object):
def __init__(self):
c = C()
>

note you're just defining some local variables here, should be self.b = B()
and self.c = C().

class C(object):
def __init__(self):
pass
>
and now i wanna do something like this:
>
a=A()
c=getattr(a, 'b.c')
>
I know this doesn't work, but what can i do to get this or a similar
functionality to get it work for this sample and for even more nested
classes?
>

You could do it manually:

c = getattr(getattr (a, 'b'), 'c')

or make it automatic:

def get_dotted_attr (obj, dotted_attr) :
for attr in dotted_attr.spl it('.') :
obj = getattr(obj, attr)
return obj

a = A()
print 'a.b.c = %s' % get_dotted_attr (a, 'b.c')

--
Cédric Lucantis

[George Sakkis]

Re: extend getattr()

On Jun 26, 7:39 am, Cédric Lucantis <o...@no-log.orgwrote:

Le Thursday 26 June 2008 13:06:53 Rotlaus, vous avez écrit :
>

Hello,

>

lets assume i have some classes:

>

class A(object):
def __init__(self):
b = B()

>

class B(object):
def __init__(self):
c = C()

>
note you're just defining some local variables here, should be self.b =B()
and self.c = C().
>

class C(object):
def __init__(self):
pass

>

and now i wanna do something like this:

>

a=A()
c=getattr(a, 'b.c')

>

I know this doesn't work, but what can i do to get this or a similar
functionality to get it work for this sample and for even more nested
classes?

>
You could do it manually:
>
c = getattr(getattr (a, 'b'), 'c')
>
or make it automatic:
>
def get_dotted_attr (obj, dotted_attr) :
for attr in dotted_attr.spl it('.') :
obj = getattr(obj, attr)
return obj
>
a = A()
print 'a.b.c = %s' % get_dotted_attr (a, 'b.c')

FYI, this feature will exist in operator.attrge tter from Python 2.6,
i.e. you'll be able to say attrgetter('b.c ')(a).

George