Question

THanks for looking into my post. I guess I have a probably a pretty simple doubt by this community standards.. but pardon me if it is too simple. I am trying to learn python.
So anyways.. I have an object which can have five attributes.
So lets say when i am initializing the class its like this

class Foo:
    def __init__ (self, argA = None, argB = None, argC = None, argD = None....)

and somewhere I have this method called get features

    def getFeatures(self):
     x = [self._argA, self._argB, self._argc... and so on]

so basically I am trying to put all these features into a list.
But here is the problem.
During initialization, as you can see all the parameters are optional..
but when I do getFeatures, I only want those features which are initialzed
Now a naive way is to write a big if else statement but as Scott Myers wrote in is book.. anytime you see yourself writign a code ” if object is of type A do something and if object is of type B do something else… then slap your self..”
What is a good way to getFeatures whcih contains only the elements which are initialized.
Thanks

Answer 1

Keep a dictionary of feature name to boolean enabled/disabled. That’s much better than having all these variables floating around.

def __init__(self, **kwargs):
    self.features = kwargs

def getFeatures(self):
    return {feature for feature, isEnabled in self.features.items() if isEnabled}

---

Example:

>>> class Foo(object):
...     def __init__(self, **kwargs):
...             self.features = kwargs
...     
...     def getFeatures(self):
...             return {feature for feature, isEnabled in self.features.items() if isEnabled}
... 
>>> x = Foo(red=True, yellow=False, green=True)
>>> x.getFeatures()
set(['green', 'red'])