[Python-ideas] A mutable alternative to namedtuple

[Luciano Ramalho]

On Wed, Mar 18, 2015 at 3:05 AM, anatoly techtonik <techtonik at gmail.com> wrote:
> On Tue, Mar 17, 2015 at 7:52 PM, Luciano Ramalho <luciano at ramalho.org> wrote:
>> Sometimes we need a simple class to hold some mutable attributes,
>> provide a nice repr, support == for testing, and support iterable
>> unpacking
>
> +1, but I think that the core problem with such proposals is that they
> lack the use cases. The only reason for me to have such class is to
> work with tabular data.
>
> For example, for querying the capability of the system, I need to build
> an inmemory table of features, and then set parameters for each
> feature one by one. sqlite/SQL is an overkill for that, and dicts are
> just not enough to do readable lookups and updates to specific
> cells, so I'd more appreciate a full table class than just its "named
> row" model.

Thanks for your input and example, Anatoly. What would the full table
class offer that could not be easily done with a simple list of items
produced with a plainclass class?

> Practical example that I came up with:
> https://bitbucket.org/techtonik/discovery/src/c4f3d306bb43772dcf3c03be8db941ff67d077b4/graphics/canvas2d/canvas2d/__init__.py?at=default#cl-22

Oh, I see you have an update method, so that's the key value add of
the Table class, right?

I see the Table and plainclass as complementary ideas. You could use
plainclass to implement Table more easily. The Table.__iter__ could
return plainclass class instances instead of OrderedDict.

Cheers,

Luciano


-- 
Luciano Ramalho
|  Author of Fluent Python (O'Reilly, 2015)
|     http://shop.oreilly.com/product/0636920032519.do
|  Professor em: http://python.pro.br
|  Twitter: @ramalhoorg