How to convert defaultdict to dict?

Question

How can I convert a defaultdict

number_to_letter defaultdict(<class 'list'>, {'2': ['a'], '3': ['b'], '1': ['b', 'a']}) 

to be a common dict?

{'2': ['a'], '3': ['b'], '1': ['b', 'a']} 

Answer 1

You can simply call dict:

>>> a defaultdict(<type 'list'>, {'1': ['b', 'a'], '3': ['b'], '2': ['a']}) >>> dict(a) {'1': ['b', 'a'], '3': ['b'], '2': ['a']} 

but remember that a defaultdict is a dict:

>>> isinstance(a, dict) True 

just with slightly different behaviour, in that when you try access a key which is missing -- which would ordinarily raise a KeyError -- the default_factory is called instead:

>>> a.default_factory <type 'list'> 

That's what you see when you print a before the data side of the dictionary appears.

So another trick to get more dictlike behaviour back without actually making a new object is to reset default_factory:

>>> a.default_factory = None >>> a[4].append(10) Traceback (most recent call last):   File "<ipython-input-6-0721ca19bee1>", line 1, in <module>     a[4].append(10) KeyError: 4 

but most of the time this isn't worth the trouble.