更新嵌套字典中的集合

Question

I'm trying to update a Set in a nested Dictionary, problem is it adds a new Set instead of updating the current Set the 2nd time.

building = {}
building.update({'APT-14D':{}})
building['APT-14D'].setdefault('amenities', set()).add(('hot-water','gas-stove','non-smoke'))
building['APT-14D'].setdefault('amenities', set()).add(('hot-water','non-stove','non-smoke'))

I receive the following:

{'APT-14D': {'amenities': {('hot-water', 'non-stove', 'non-smoke'), ('hot-water', 'gas-stove', 'non-smoke')}}}

instead of:

{'APT-14D': {'amenities': {('hot-water', 'non-stove', 'non-smoke')}}}

How would I update the current value instead of making a new Set inside the nested dictionary?

PS The different values are non-stove and gas-stove

Answer 1

You aren't making a new set, you are adding a different tuple to your set . If you want to add each of the individual elements of your tuple to the set, use .update :

In [4]: building = {}
   ...: building.update({'APT-14D':{}})
   ...: building['APT-14D'].setdefault('amenities', set()).update(('hot-water','gas-stove','non-smoke'))
   ...: building['APT-14D'].setdefault('amenities', set()).update(('hot-water','non-stove','non-smoke'))
   ...:

In [5]: building
Out[5]:
{'APT-14D': {'amenities': {'gas-stove',
   'hot-water',
   'non-smoke',
   'non-stove'}}}

Rereading your question, I've notice that isn't even really what you want. It seems now that you don't even want a set, just a tuple, and just replace that tuple with whatever new value comes:

In [16]: building = {'APT-14D':{}}

In [17]: building['APT-14D']['amenities'] =  ('hot-water','gas-stove','non-smoke')

In [18]: building['APT-14D']['amenities'] =  ('hot-water','non-stove','non-smoke')

In [19]: building
Out[19]: {'APT-14D': {'amenities': ('hot-water', 'non-stove', 'non-smoke')}}