Using varibles of a class inside nested classes in Python

Question

I want something like this. I cannot pass pass the parent instance to Child class

 class Outer:
    def __init__(self, logging):
        self.logging 
        self.logger = logging.getLogger('Parent')

    class Inner(SomeBaseClass):
        def __init__(self, *args):
            Outer.logger.info('initializing Child with %', ' '.join(args))

  logging.config.fileConfig('logging.conf')
  outerObject = Outer(logging)
  .
  .

  .
  # both inner1 and inner2 use same logger object
  # intent: no need to pass the logger
  inner1 = outerObject.Inner('xyzz')
  inner2 = outerObject.Inner('abc')

how to implement this? or any better method to do the same?

It is not clear what exactly you want, here the name is `Child` but it is not a descendant of `Parent` class, but `SomeBaseClass`. — dashesy, May 12 '15 at 15:22
sorry for the confusion - renamed Parent --> Outer and Child --> Inner — vanangamudi, May 12 '15 at 15:26

score 2 · Accepted Answer · answered May 12 '15 at 16:02

class Inner(SomeBaseClass):
    def __init__(self, logger, *args):
        self.logger = logger
        self.logger.info('initializing Child with %', ' '.join(args))

class Outer(object):
    def __init__(self, logging, logger_name='Parent'):
        self.logging = logging
        self.logger = self.logging.getLogger(logger_name)

    def get_inner(self, *args):
        return Inner(self.logger, *args)

logging.config.fileConfig('logging.conf')
outerObject = Outer(logging)

inner1 = outerObject.get_inner('xyzz')
inner2 = outerObject.get_inner('abc')

Looking good?

There's no need to pass `logging` as an argument; it's a global module reference. — chepner, May 12 '15 at 16:16

score 0 · Answer 2 · answered May 12 '15 at 15:43

0

getLogger is designed so that you can always retrieve the desired Logger instance by passing the right name as an argument. You don't need to pass a reference to the logging module to Outer.__init__, either.

class Outer:
    def __init__(self):
        self.logger = logging.getLogger('Parent')

    class Inner(SomeBaseClass):
        def __init__(self, *args):
            logger = logging.getLogger('Parent')
            logger.info('initializing Child with %', ' '.join(args))

Note that Outer.logger would be different than self.logger for any particular instance of Outer anyway.

answered May 12 '15 at 15:43

chepner

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It is not just the logging module. I need to access some other instance variables of Outer class inside Inner Class. That is why I create a _parentObject_ and then use that object to create Inner class objects – vanangamudi May 12 '15 at 15:54
@vanangamudi read this http://stackoverflow.com/questions/2024566/access-outer-class-from-inner-class-in-python (inner classes in Python aren't like Java's) – sirfz May 12 '15 at 16:00

Using varibles of a class inside nested classes in Python

2 Answers2