@AR,
On 28/05/20 8:41 AM, Chris Angelico wrote:
On Thu, May 28, 2020 at 6:27 AM Abdur-Rahmaan Janhangeer
<arj.pyt...@gmail.com> wrote:
Thanks,
Actually i want to keep a reference from B to all A
instantiated like in the case of z
I have class A and i want to call class B via A
You can have
def x(self, *args, **kwargs):
return A(*args, **kwargs)
but was wondering if we could keep track while
doing it via z = ...
Okay, now I think I get what you're after. Let's simplify and clarify
things. Let me know if I'm misinterpreting.
1) You have a container class that can instantiate objects of a thing class
2a) You wish for the container to be aware of all things it has created - OR -
2b) You wish for the Thing to be aware of all containers that have created them
3) You want this to happen automatically.
I'm not sure which way round you're trying to do this, so I'll try to
answer both. Your Container (Hooman) can construct multiple Things
(Button), and other classes could also construct Things. So you need
some way to automatically register the Thing as you create it.
The easiest way to do this would, I think, be to have your Container
subclass a utility class, and then use self.Button() instead of
Button(). That can take care of registering the button in some sort of
list, and then it can still return the button in case you need it for
something else.
Would that work? Or am I completely off on my analysis?
Here's some sample code, which may give you some ideas (intriguingly it
comes from my playing-about with a project @Chris described (some time
back), which includes the need to 'register' sub-components and to keep
a count of them):
# PSL
import collections
from itertools import count
class Link():
'''Contain original link, manipulate for presentation,
and retain for later action.
'''
ID = count( 0 )
instances = []
def __init__( self, token:Token, )->None:
'''Instantiate.'''
self.token = token
self.linkNR:int = next( self.ID ) #linkNR
Link.instances.append( self ) #form a register of
instances/links
self.URL:str = ""
...more methods here - likely irrelevant to your needs...
class LinksRegister( collections.UserList ):
'''Links available for use within application.'''
def __iter__( self ):
'''Generator.'''
for link in self.data:
yield link
def register_links( self, cls ):
'''Register all links.'''
self.data = cls.instances
Once all of the Link() objects have been ascertained, we can make use of
the class-attributes:
links_register.register_links( Link )
NB in this scenario it is only necessary to register once - all of the
links at-once, cf registering each link as it is itself instantiated.
Also, that each Link() object is not aware that it is/will be 'registered'!
Later, when it is necessary to carry-out the same action on each of the
objects, we can use the register's iterator/generator (as above).
Critique/other ideas welcome...
--
Regards =dn
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