Hello,
one way:
(apply
merge-with
conj
{}
(for [nd d nd-pair nd face nd-pair]
{face nd}))
The idea is (as is generally the case for me when trying to move from
imperative code to functional), is to try not to do too many things in a
single step.
So here, first I extract from the "for" "pieces of information", individual
pairs of face => containing-node into an intermediate sequence.
Then I consume this sequence with merge-with.
I could also consume this sequence with reduce, of course:
(reduce (fn [m fnd] (merge-with conj m fnd) (for ...))
HTH,
--
Laurent
2010/12/3 Sunil S Nandihalli <sunil.nandiha...@gmail.com>
> Hello everybody,
>
> I would like to know as to how I would write the following code in a more
> idiomatic way.
>
>
>
>
>
> (let [mp (atom {})
>
>
> d [#{#{1 2}
>
>
> #{3 4}} ;node1
>
>
> #{#{5 6}
>
>
> #{7 8}} ;node2]]
>
>
> (dorun (for [nd d nd-pair nd face nd-pair]
>
>
> (swap! mp update-in [face] #(conj % nd))))
>
>
> @mp)
>
>
>
>
> ; if you consider that points 1 2 3 4 form the node node1 and 5 6 7 8 form
> node2
>
>
> ;I would like a map in the opposite direction ..
>
>
> ;i.e. I should be able to find out all the nodes of which 1 is part of and
>
>
> ;that is what the above code is doing.. but would like to know as to what
>
>
> ;would be a more idiomatic way of doing this.
>
>
>
>
>
> https://gist.github.com/726773
>
>
>
>
> I don't like the fact that I am using atom and swap .. can anybody suggest a
> better way to do it?
>
>
>
> Thanks,
> Sunil.
>
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