Get name of dictionary

Question

I find myself needing to iterate over a list made of dictionaries and I need, for every iteration, the name of which dictionary I'm iterating on.

Here's an MRE (Minimal Reproducible Example).
Contents of the dicts are irrelevant:

dict1 = {...}
dicta = {...}
dict666 = {...}

dict_list = [dict1, dicta, dict666]

for dc in dict_list:
    # Insert command that should replace ???
    print 'The name of the dictionary is: ', ???

If I just use dc where ??? is, it will print the entire contents of the dictionary. How can I get the name of the dictionary being used?

Answer 1

Objects don't have names in Python, a name is an identifier that can be assigned to an object, and multiple names could be assigned to the same one.

However, an object-oriented way to do what you want would be to subclass the built-in dict dictionary class and add a name property to it. Instances of it would behave exactly like normal dictionaries and could be used virtually anywhere a normal one could be.

class NamedDict(dict):
    def __init__(self, *args, **kwargs):
        try:
            self._name = kwargs.pop('name')
        except KeyError:
            raise KeyError('a "name" keyword argument must be supplied')
        super(NamedDict, self).__init__(*args, **kwargs)

    @classmethod
    def fromkeys(cls, name, seq, value=None):
        return cls(dict.fromkeys(seq, value), name=name)

    @property
    def name(self):
        return self._name

dict_list = [NamedDict.fromkeys('dict1', range(1,4)),
             NamedDict.fromkeys('dicta', range(1,4), 'a'),
             NamedDict.fromkeys('dict666', range(1,4), 666)]

for dc in dict_list:
    print 'the name of the dictionary is ', dc.name
    print 'the dictionary looks like ', dc

Output:

the name of the dictionary is  dict1
the dictionary looks like  {1: None, 2: None, 3: None}
the name of the dictionary is  dicta
the dictionary looks like  {1: 'a', 2: 'a', 3: 'a'}
the name of the dictionary is  dict666
the dictionary looks like  {1: 666, 2: 666, 3: 666}