Hi,
I have a peculiar sequence of nested maps which have the following structure -
{:a 1 :b 1 :c []}
The keys :a & :b always have scalar values but the :c key can have
either an empty vector or a vector of maps of the same kind. For
example -
{:a 1 :b 1 :c [{:a 1 :b 1 :c [{:a 1 :b 1 :c []}]} {:a 1 :b 1 :c []}]}
The task is to write a function `flatten-maps` which will take a
vector of such maps and will return a sequence of maps with only the
:a & :b keys.
Example -
(def data [{:a 1 :b 1 :c [{:a 1 :b 1 :c [{:a 1 :b 1 :c []}]} {:a 1 :b
1 :c []}]} {:a 1 :b 1 :c [{:a 1 :b 1 :c [{:a 1 :b 1 :c []}]} {:a 1 :b
1 :c []}]}])
(flatten-maps data)
;=> ({:a 1, :b 1} {:a 1, :b 1} {:a 1, :b 1} {:a 1, :b 1} {:a 1, :b 1}
{:a 1, :b 1} {:a 1, :b 1} {:a 1, :b 1})
My solution -
(defn flatten-maps
[ms]
(if-let [ms (seq ms)]
(reduce (fn [v m]
(if (seq (:c m))
(concat (conj v (dissoc m :c))
(flatten-maps (:c m)))
(conj v (dissoc m :c))))
[]
ms)
[]))
The goal is to write something which is fast using idiomatic Clojure.
This is just a fun exercise, nothing serious :)
Regards,
BG
--
Baishampayan Ghose
b.ghose at gmail.com
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