How to automate accessor definition?

[Chris Rebert]

On Sat, Mar 20, 2010 at 3:15 PM, kj <no.email at please.post> wrote:
> I need to create a class solely for the purpose of encapsulating
> a large number of disparate data items.  At the moment I have no
> plans for any methods for this class other than the bazillion
> accessors required to access these various instance variables.
> (In case it matters, this class is meant to be a private helper
> class internal to a module, and it won't be subclassed.)

If it's just a completely dumb struct-like class, you might consider
something like:
http://docs.python.org/library/collections.html#collections.namedtuple

> What is "best practice" for implementing this sort of class
> *succinctly* (i.e. without a lot of repetitive accessor code)?

Is there any good reason you can't just use straight instance
variables? Python ain't Java; vanilla, boilerplate accessor methods
should almost always be avoided.

> Also, one more question concerning syntax.  Suppose that i represents
> an instance of this class.  Is it possible to define the class to
> support this syntax
>
>  val = i.field
>  i.field += 6
>
> ...rather than this one
>
>  val = i.get_field()
>  i.set_field(i.get_field() + 6)
>
> ?

Yes, using the magic of the property() function:
http://docs.python.org/library/functions.html#property

Cheers,
Chris
--
http://blog.rebertia.com