[Rd] Define 'in' for new class
pdalgd at gmail.com
Tue Aug 12 09:28:05 CEST 2014
On 12 Aug 2014, at 08:29 , Simon Knapp <sleepingwell at gmail.com> wrote:
> Hi List,
> Is it possible to define how 'in' works for an object of a specific class
> (to achieve a similar result to implementing the iterator protocol in a
> class Python)?
No, because 'in' doesn't really exist, it is "syntactic sugar" to sweeten a call to the "for" function with its three arguments. E.g.
So what you're really asking for is something like a `for` with class dispatch or the two first arguments replaced by an iterator mechanism. That's not in the cards, at least at the moment, but I suppose it isn't completely out of the question either -- ideas of this sort get bandied around occasionally. It would require changes to R's internals; it is not something you can do in (say) a package.
> Simon Knapp
> [[alternative HTML version deleted]]
> R-devel at r-project.org mailing list
Peter Dalgaard, Professor,
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