CODEWITHSUNDEEP
pythonclass
user14443915
user14443915

Reputation:

Object like a list or dict

i Have a class Vertex like:

class Vertex:
    def __init__(self,key):
        self.id = key
        self.connectedTo = {}
        self.neighbors = {}
        
        self.dict = {}
        
        self.community = []
        
        self.inside = 0
        self.been = 0

and I want to put all those selfs community, inside, been, (...) and some more attributes in one dictionary that will be iterable so:

vertex['inside'] = 0

Right now some of my attributes are in self.dict so I'm using for example: vertex.dict['visited'] = 1 but can I skip .dict and write it as vertex['visited'] = 1?

Upvotes: 0

Views: 54

Answers (3)

martineau
martineau

Reputation: 123413

You can create a class like that by overriding the special methods associated with accessing the elements as illustrated below:

class Vertex:
    def __init__(self, key):
        super().__setattr__('_dict', {})
        self['id'] = key
        self['connectedTo'] = {}
        self['neighbors'] = {}
        self['community'] = []
        self['inside'] = 0
        self['been'] = 0

    def __setitem__(self, key, value):
        self._dict[key] = value

    def __setattr__(self, name, value):
        _dict = super().__getattribute__('_dict')
        _dict[name] = value

    def __getattr__(self, name):
        _dict = super().__getattribute__('_dict')
        return _dict[name]


vertex = Vertex(42)
print('Upon creation:')
print(f'{vertex._dict=}')
vertex.community.append((1,2,3))
vertex.inside = 17
vertex.connectedTo['foobar'] = 20210613
print()
print('After modifications:')
print(f'{vertex._dict=}')

Output:

Upon creation:
vertex._dict={'id': 42, 'connectedTo': {}, 'neighbors': {}, 'community': [], 'inside': 0, 'been': 0}

After modifications:
vertex._dict={'id': 42, 'connectedTo': {'foobar': 20210613}, 'neighbors': {}, 'community': [(1, 2, 3)], 'inside': 17, 'been': 0}

Upvotes: 0

Apo
Apo

Reputation: 338

You need to use the getitem and setitem methode like :

class Vertex:
def __init__(self,key):
    ...
    self.data = {'community':self.community, ...}

def __getitem__(self, key):
    return self.data[key]

def __setitem__(self, key, value):
    self.data[key] = value

Need to find something else for the setitem method this is not going to work perfectly here, it was just an example, but the getitem will work for sure.

Why it will not work :

class Vertex:
def __init__(self,key):
    self.a = 4
    self.data = {'a': self.a}
def __getitem__(self, key):
    return self.data[key]
def __setitem__(self, key, value):
    self.data[key] = value

then :

>>> t = Vertex(1)
>>> t['a']
4
>>> t['a'] = 3
>>> t['a']
3
>>> t.a
4

The value in the dict will be updated but not the attribute

Upvotes: 0

Guy
Guy

Reputation: 50809

You can use __dict__ on an instance of Vertex

vertex = Vertex(1)
d = vertex.__dict__
d['visited'] = 1
print(vertex.visited) # 1

Upvotes: 1

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