What is getattr() exactly and how do I use it?

Question

I\'ve recently read about the getattr() function. The problem is that I still can\'t grasp the idea of its usage. The only thing I understand about getattr() is

Answer 1

Quite frequently when I am creating an XML file from data stored in a class I would frequently receive errors if the attribute didn't exist or was of type None. In this case, my issue wasn't not knowing what the attribute name was, as stated in your question, but rather was data ever stored in that attribute.

class Pet:
    def __init__(self):
        self.hair = None
        self.color = None

If I used hasattr to do this, it would return True even if the attribute value was of type None and this would cause my ElementTree set command to fail.

hasattr(temp, 'hair')
>>True

If the attribute value was of type None, getattr would also return it which would cause my ElementTree set command to fail.

c = getattr(temp, 'hair')
type(c)
>> NoneType

I use the following method to take care of these cases now:

def getRealAttr(class_obj, class_attr, default = ''):
    temp = getattr(class_obj, class_attr, default)
    if temp is None:
        temp = default
    elif type(temp) != str:
        temp = str(temp)
    return temp

This is when and how I use getattr.