pythondictionarysyntaxnestednested-properties

How to use a dot "." to access members of dictionary?


How do I make Python dictionary members accessible via a dot "."?

For example, instead of writing mydict['val'], I'd like to write mydict.val.

Also I'd like to access nested dicts this way. For example

mydict.mydict2.val 

would refer to

mydict = { 'mydict2': { 'val': ... } }

Solution

  • You can do it using this class I just made. With this class you can use the Map object like another dictionary(including json serialization) or with the dot notation. I hope to help you:

    class Map(dict):
        """
        Example:
        m = Map({'first_name': 'Eduardo'}, last_name='Pool', age=24, sports=['Soccer'])
        """
        def __init__(self, *args, **kwargs):
            super(Map, self).__init__(*args, **kwargs)
            for arg in args:
                if isinstance(arg, dict):
                    for k, v in arg.iteritems():
                        self[k] = v
    
            if kwargs:
                for k, v in kwargs.iteritems():
                    self[k] = v
    
        def __getattr__(self, attr):
            return self.get(attr)
    
        def __setattr__(self, key, value):
            self.__setitem__(key, value)
    
        def __setitem__(self, key, value):
            super(Map, self).__setitem__(key, value)
            self.__dict__.update({key: value})
    
        def __delattr__(self, item):
            self.__delitem__(item)
    
        def __delitem__(self, key):
            super(Map, self).__delitem__(key)
            del self.__dict__[key]
    

    Usage examples:

    m = Map({'first_name': 'Eduardo'}, last_name='Pool', age=24, sports=['Soccer'])
    # Add new key
    m.new_key = 'Hello world!'
    # Or
    m['new_key'] = 'Hello world!'
    print m.new_key
    print m['new_key']
    # Update values
    m.new_key = 'Yay!'
    # Or
    m['new_key'] = 'Yay!'
    # Delete key
    del m.new_key
    # Or
    del m['new_key']