Is there a recursive version of the dict.get() built-in?

Question

I have a nested dictionary object and I want to be able to retrieve values of keys with an arbitrary depth. I\'m able to do this by subclassing dict:

Answer 1

You can actually achieve this really neatly in Python 3, given its handling of default keyword arguments and tuple decomposition:

In [1]: def recursive_get(d, *args, default=None):
   ...:     if not args:
   ...:         return d
   ...:     key, *args = args
   ...:     return recursive_get(d.get(key, default), *args, default=default)
   ...: 

Similar code will also work in python 2, but you'd need to revert to using **kwargs, as you did in your example. You'd also need to use indexing to decompose *args.

In any case, there's no need for a loop if you're going to make the function recursive anyway.

You can see that the above code demonstrates the same functionality as your existing method:

In [2]: d = {'foo': {'bar': 'baz'}}

In [3]: recursive_get(d, 'foo')
Out[3]: {'bar': 'baz'}

In [4]: recursive_get(d, 'foo', 'bar')
Out[4]: 'baz'

In [5]: recursive_get(d, 'bogus key', default='nonexistent key')
Out[5]: 'nonexistent key'