Hi Boris,
Boris Mizhen a écrit :
> I am starting to learn clojure. I would appreciate comments on the
> utility function below.
> Coding style, idiomatic Clojure, comment style, efficiency, naming
> conventions, indentations (used slime) ... anything I should
> improve :)
>
> (defn seq-to-multimap [s key-fn]
> "takes a sequence s of possibly repeating elements
> and converts it to a map, where keys are obtained by applying key-
> fn
> to elements of s and values are sequence of all elements of s with
> the
> particular key"
> (reduce
> (fn [amap item]
> (let [key (key-fn item)]
> (assoc amap key
> (if-let [it (amap key)]
> (conj it item)
> (list item)))))
> {} s))
>
First, you misplaced the docstring: it comes before the args vector.
Using a default return value, you can rewrite the (if-let...) as (conj
(amap key ()) item).
> user> (seq-to-multimap [1 :key :key 2 3 3 nil] #(identity %1))
> {nil (nil), 3 (3 3), 2 (2), :key (:key :key), 1 (1)}
>
Here you don't need to write #(identity %1), "identity" suffices.
> Would it be better to have this function to create a list of lists
> using an equality op instead?
>
I think it's a better choice to have it return a map because, to compute
the result, you need to efficiently index by key.
--
Professional: http://cgrand.net/ (fr)
On Clojure: http://clj-me.blogspot.com/ (en)
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