I have an iterable of keys like ('a', 'b', 'c') that I want to correspond to an entry in a dictionary I am building. I am looking for a one-linerish way to build this dictionary from multiple tuples.
Input:
keys = ('a', 'b', 'c') value = 'bar' Output:
{'a': {'b': {'c': 'bar'}}} I have been trying things using defaultdict, but haven't really gotten the grasp of it. The one-liner requirement is pretty soft, but I was hoping to get a really small footprint for this.
You can use reduce1 here:
reduce(lambda x, y: {y: x}, keys[::-1], value) Or, use the iterator returned by reversed:
reduce(lambda x, y: {y: x}, reversed(keys), value)
A lot of people might not like this too much. Unless you're really into functional programming in python, this is a bit opaque. A simpler solution takes only 3 lines:
>>> keys = ('a', 'b', 'c') >>> value = 'bar' >>> for c in reversed(keys): ... value = {c: value} ... >>> value {'a': {'b': {'c': 'bar'}}} and doesn't rely on any slightly obscure builtin functions.
FWIW, I'm not sure which version I prefer ...
1functools.reduce in python3.x which also exists in python2.6+ to ease py3k transitions IIRC
