python: building 3-D dictionary

We're using 2.4 so don't have defaultdict. Her's a way to create one using dict() and setdefault():

>>> hid=dict()
>>> hid.setdefault('H',0)
0
>>> hid.setdefault('I',0)
0
>>> bkd=dict()
>>> bkd
{}
>>> bkd.setdefault('Z',hid)
{'I': 0, 'H': 0}
>>> bkd
{'Z': {'I': 0, 'H': 0}}
>>> bkd.setdefault('CH',hid)
{'I': 0, 'H': 0}
>>> bkd
{'CH': {'I': 0, 'H': 0}, 'Z': {'I': 0, 'H': 0}}
>>> epd=dict()
>>> epd.setdefault('E',bkd)
{'CH': {'I': 0, 'H': 0}, 'Z': {'I': 0, 'H': 0}}
>>> epd.setdefault('P',bkd)
{'CH': {'I': 0, 'H': 0}, 'Z': {'I': 0, 'H': 0}}
>>> epd
{'P': {'CH': {'I': 0, 'H': 0}, 'Z': {'I': 0, 'H': 0}}, 'E': {'CH': {'I': 0, 'H': 0}, 'Z': {'I': 0, 'H': 0}}}

Now use it:

>>> ep=['E','P']
>>> bk=['Z','CH']
>>> hi=['H','I']
>>> i=0
>>> for e in ep:
...   for b in bk:
...     for h in hi:
...       epd[e][b][h]=i
...       i+=1
...
>>> epd
{'P': {'CH': {'I': 7, 'H': 6}, 'Z': {'I': 7, 'H': 6}}, 'E': {'CH': {'I': 7, 'H': 6}, 'Z': {'I': 7, 'H': 6}}}

>>> epd['E']['Z']['H']
6

I want to start with lists and build dictionaries from there. Here's the start of that automation:

>>> def setDefaults(k,d):
...   for key in k:
...     d.setdefault(key,0)
...
>>> kay=['A','B','C','D']
>>> dee=dict()
>>> setDefaults(kay,dee)
>>> dee
{'A': 0, 'C': 0, 'B': 0, 'D': 0}

Now update setDefaults to take the default initializer as a parameter:

>>> def setDefaults(k,d,i):
...   for key in k:
...     d.setdefault(key,i)
...
>>> kay
['A', 'B', 'C', 'D']
>>> d2=dict()
>>> setDefaults(kay,d2,2)
>>> d2
{'A': 2, 'C': 2, 'B': 2, 'D': 2}

OK, now here we start with three lists and build a 3-d dictionary using the setDefaults() method:

>>> kay
['A', 'B', 'C', 'D']
>>> ell=['X','Y','Z']
>>> grk=['pi','ro','lamtha','tau']
>>> kay_ell=dict()
>>> kay_d=dict()
>>> setDefaults(kay,kay_d,0)
>>> kay_d
{'A': 0, 'C': 0, 'B': 0, 'D': 0}
>>> setDefaults(ell,kay_ell,kay_d)
>>> ell
['X', 'Y', 'Z']
>>> kay_ell
{'Y': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'X': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'Z': {'A': 0, 'C': 0, 'B': 0, 'D': 0}}
>>> kay_ell_grk=dict()
>>> setDefaults(grk,kay_ell_grk,kay_ell)
>>> kay_ell_grk
{'tau': {'Y': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'X': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'Z': {'A': 0, 'C': 0, 'B': 0, 'D': 0}}, 'pi': {'Y': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'X': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'Z': {'A': 0, 'C': 0, 'B': 0, 'D': 0}}, 'ro': {'Y': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'X': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'Z': {'A': 0, 'C': 0, 'B': 0, 'D': 0}}, 'lamtha': {'Y': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'X': {'A': 0, 'C': 0, 'B': 0, 'D': 0}, 'Z': {'A': 0, 'C': 0, 'B': 0, 'D': 0}}}
>>>