Re: multi dimensional dictionary

[Gary Herron]

Alok Kumar wrote:
> Dear All,
>
> I am using dictionary for filling my xpath parsed data.
>
> I wanted to use in the following manner.
>
> mydict[index] ["key1"] ["key2"] #Can someone help me with right
> declaration.
>
> So that I can fill my XML xpath parsed data
>
> mydict[0] ["person"] ["setTime"] = "12:09:30"
> mydict[0] ["person"] ["clrTime"] = "22:09:30"

That kind of thing can be done, but there's a better way perhaps:

Create keys for a single level dictionary which are tuples composed of
the sequence of keys you would have used in your multidimensional
dictionary.

mydict[(0,"person","setTime")] = "12:09:30"
mydict[(0,"person","clrTime")] = "22:09:30"

Would that work for you?

Gary Herron

>
> Can someone help me with right declaration usages. Your help will be
> highly appreciated.
>
> Regards
> Alok
> ------------------------------------------------------------------------
>
> --
> http://mail.python.org/mailman/listinfo/python-list

[Hrvoje Niksic]

Gary Herron <ghe...@islandtraining.com> writes:

> mydict[(0,"person","setTime")] = "12:09:30"
> mydict[(0,"person","clrTime")] = "22:09:30"

Note that this is more succinctly written as:

mydict[0, "person", "setTime"] = "12:09:30"

with the added advantage that it looks like a multi-dimensional array.
:-)

The only problem with this approach is that when you want to iterate
over, say, mydict[0], or mydict[0]["person"], it's not possible
without traversing the entire dict.

[Peter Otten]

Gary Herron wrote:

> Alok Kumar wrote:
>> Dear All,
>>
>> I am using dictionary for filling my xpath parsed data.
>>
>> I wanted to use in the following manner.
>>
>> mydict[index] ["key1"] ["key2"] #Can someone help me with right
>> declaration.
>>
>> So that I can fill my XML xpath parsed data
>>
>> mydict[0] ["person"] ["setTime"] = "12:09:30"
>> mydict[0] ["person"] ["clrTime"] = "22:09:30"

[I didn't see the original post]

>>> from collections import defaultdict
>>> def make_inner():
... return defaultdict(lambda: defaultdict(make_inner))
...
>>> mydict = make_inner()

>>> mydict[0]["person"]["setTime"] = "12:09:30"

>>> mydict[0]["person"]["shoes"]["color"] = "bright yellow"
>>> mydict
defaultdict(<function <lambda> at 0x2b7afd0025f0>, {0: defaultdict(<function
make_inner at 0x2b7afd002578>, {'person': defaultdict(<function <lambda> at
0x2b7afd002668>, {'setTime': '12:09:30', 'shoes': defaultdict(<function
make_inner at 0x2b7afd002578>, {'color': 'bright yellow'})})})})

If that looks too messy, try a subclass:

>>> class Dict(defaultdict):
... def __init__(self):
... defaultdict.__init__(self, Dict)
... def __repr__(self):
... return dict.__repr__(self)
...
>>> mydict = Dict()

>>> mydict[0]["person"]["setTime"] = "12:09:30"
>>> mydict

{0: {'person': {'setTime': '12:09:30'}}}
>>> mydict[0]["person"]["shoes"]["color"] = "bright yellow"
>>> mydict
{0: {'person': {'setTime': '12:09:30', 'shoes': {'color': 'bright
yellow'}}}}

Peter

[Paul McGuire]

On May 28, 3:11 am, Peter Otten <__pete...@web.de> wrote:
> Gary Herron wrote:
> > Alok Kumar wrote:
> >> Dear All,
>
> >> I am using dictionary for filling my xpath parsed data.
>
> >> I wanted to use in the following manner.
>
> >> mydict[index] ["key1"] ["key2"]    #Can someone help me with right
> >> declaration.
>
> >> So that I can fill my XML xpath parsed data
>
> >> mydict[0] ["person"] ["setTime"] = "12:09:30"
> >> mydict[0] ["person"] ["clrTime"] = "22:09:30"
>
> [I didn't see the original post]
>
> >>> from collections import defaultdict
> >>> def make_inner():
>
> ...     return defaultdict(lambda: defaultdict(make_inner))
> ...>>> mydict = make_inner()
> >>> mydict[0]["person"]["setTime"] = "12:09:30"
> >>> mydict[0]["person"]["shoes"]["color"] = "bright yellow"
> >>> mydict
>

<snip>

When this has come up in previous threads, I think this was the best
solution that was proposed:

from collections import defaultdict

class recursivedefaultdict(defaultdict):
def __init__(self):
self.default_factory = type(self)

Here is this recursivedefaultdict in action:

data = [
('A','B','Z',1),
('A','C','Y',2),
('A','C','X',3),
('B','A','W',4),
('B','B','V',5),
('B','B','U',6),
('B','D','T',7),
]

table = recursivedefaultdict()

for k1,k2,k3,v in data:
table[k1][k2][k3] = v

for kk in sorted(table.keys()):
print "-",kk
for jj in sorted(table[kk].keys()):
print " -",jj
for ii in sorted(table[kk][jj].keys()):
print " -",ii,table[kk][jj][ii]

Prints:

- A
- B
- Z 1
- C
- X 3
- Y 2
- B
- A
- W 4
- B
- U 6
- V 5
- D
- T 7

-- Paul