Best way to define multidimensional dictionaries in python?

Question

hi all, I'm currently using the method below to define a multidimensional dictionary in python. Question is... is this the preferred way of defining multidim dicts?

from collections import defaultdict
def site_struct(): return defaultdict(board_struct)
def board_struct(): return defaultdict(user_struct)
def user_struct(): return dict(pageviews=0,username='',comments=0)
userdict = defaultdict(site_struct)

to get the following structure

userdict['site1']['board1']['username'] = 'tommy'

I'm also using this to incement counters on the fly for a user without having to check if a key exists or is set to 0 already. E.g.:

userdict['site1']['board1']['username']['pageviews'] += 1

Answer 1

Tuples are hashable. Probably I'm missing the point, but why don't you use a standard dictionary with the convention that the keys will be triples? For example:

userdict = {}
userdict[('site1', 'board1', 'username')] = 'tommy'

Answer 2

This is a pretty subjective question from my perspective. For me, the real question would be at what point do you promote this nested data structure to objects with methods to insulate you from changes. However, I've been known to create large prototyping namespaces with the following:

from collections import defaultdict

def nesteddict(): 
  return defaultdict(nesteddict)