On Tue, 13 Nov 2007 08:02:08 -0800, braver wrote:
> Greetings: I wonder how does one uses single-name variables to refer
> to nested sunhashes (subdictionaries). Here's an example:
That's possible and you do it in your example.
> In [41]: orig = { 'abra':{'foo':7, 'bar':9}, 'ca':{}, 'dabra':{'baz':
> 4} }
>
> In [42]: orig
> Out[42]: {'abra': {'bar': 9, 'foo': 7}, 'ca': {}, 'dabra': {'baz': 4}}
>
> In [43]: h = orig['ca']
Here you are getting the reference to the empty dictionary and bind it to
the name `h`.
> In [44]: h = { 'adanac':69 }
>
> In [45]: h
> Out[45]: {'adanac': 69}
>
> In [46]: orig
> Out[46]: {'abra': {'bar': 9, 'foo': 7}, 'ca': {}, 'dabra': {'baz': 4}}
>
> I want to change orig['ca'], which is determined somewhere else in a
> program's logic, where subhashes are referred to as h -- e.g., for x
> in orig: ... . But assigning to h doesn't change orig.
Correct. Changing the dictionary bound to `h` changes it::
h = orig['ca']
h['adanac'] = 69
> Yet since names are not exactly references, something else is needed
> for generalized ngram multi-level counting hash -- what?
Names *are* implemented as references to objects, but binding the name to
a different object has no effect on the object bound to that name before.
Ciao,
Marc 'BlackJack' Rintsch
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