Python 101: How to Change a Dict Into a Class
I work with a lot of dictionaries at my job. Sometimes the dictionaries get really complicated with lots of nested data structures embedded within them. Recently I got a little tired of trying to remember all the keys in my dictionaries so I decided to change one of my dictionaries into a class so I could access the keys as instance variables / attributes. If you’ve ever gotten sick
Here’s one simple way to do it:
######################################################################## class Dict2Obj(object): """ Turns a dictionary into a class """ #---------------------------------------------------------------------- def __init__(self, dictionary): """Constructor""" for key in dictionary: setattr(self, key, dictionaryPython dict like object) #---------------------------------------------------------------------- if __name__ == "__main__": ball_dict = ball = Dict2Obj(ball_dict)
This code uses setattr to add each of the keys as attributes to the class. The following shows some examples of how it works:
>>> ball.color ‘blue’ >>> ball.size ‘8 inches’ >>> print ball
When we print the ball object, we get a rather unhelpful string back from the class. Let’s override the __repr__ method of our class and make it print out something a little more useful:
######################################################################## class Dict2Obj(object): """ Turns a dictionary into a class """ #---------------------------------------------------------------------- def __init__(self, dictionary): """Constructor""" for key in dictionary: setattr(self, key, dictionaryPython dict like object) #---------------------------------------------------------------------- def __repr__(self): """""" return "" % self.__dict__ #---------------------------------------------------------------------- if __name__ == "__main__": ball_dict = ball = Dict2Obj(ball_dict)
Now if we print out the ball object, we’ll get the following:
This is a little unintuitive in that it is printing out a dictionary using the class’s internal __dict__ rather than just the attribute names. This is more a matter of taste than anything, but let’s try to get just the method names:
######################################################################## class Dict2Obj(object): """ Turns a dictionary into a class """ #---------------------------------------------------------------------- def __init__(self, dictionary): """Constructor""" for key in dictionary: setattr(self, key, dictionaryPython dict like object) #---------------------------------------------------------------------- def __repr__(self): """""" attrs = str([x for x in self.__dict__]) return "" % attrs #---------------------------------------------------------------------- if __name__ == "__main__": ball_dict = ball = Dict2Obj(ball_dict)
Here we just loop over the contents of __dict__ and return a string with just a list of the keys, which match up with the attribute names. You could have also done it like this:
attrs = str([x for x in dir(self) if "__" not in x])
I’m sure there are lots of other ways to accomplish this sort of thing as well. Regardless, I found this little piece of code helpful in some of my work. Hopefully you’ll find it useful too.