Wrote the following function which did the trick:
(defn partn [data]
(let
[add-mapping
(fn [m v]
(assoc m v (filter #(= v (:a1 %)) data)))]
(reduce add-mapping {} (set (map #(:a1 %) data))))
On Sat, Apr 16, 2011 at 8:15 PM, shuaybi <[email protected]> wrote:
> I am trying to write a function but can't get it right. I need to loop
> through my data records and for each unique value of :a1 I need to
> partition the data and create a resulting map so that the key is value
> of :a1 and the associated value of this key is all records with that
> value of :a1. Better explained with code, where given the definition
> of data below, I need to write a function that will return the
> definition of "result" below.
>
> ;data is a list of records (maps)
> (def data '({:a1 2 :a2 34 :a3 76 :a4 87},
> {:a1 3 :a2 30 :a3 38 :a4 39},
> {:a1 2 :a2 67 :a3 32 :a4 38},
> {:a1 4 :a2 47 :a3 73 :a4 38},
> {:a1 3 :a2 84 :a3 86 :a4 63}))
>
> ;result should be a map, keyed by unique values of :a1 and containing
> all records for that value of :a1
> (def result '{2 ({:a1 2 :a2 34 :a3 76 :a4 87}, {:a1 2 :a2 67 :a3
> 32 :a4 39}), ;list of records where :a1 = 2
> 3 ({:a1 3 :a2 30 :a3 38 :a4 39}, {:a1 3 :a2 84 :a3
> 86 :a4 63}), ;list of records where :a1 = 3
> 4 ({:a1 4 :a2 47 :a3 73 :a4 38}) ;list of records
> where :a1 = 4
> })
>
> (defn get-val-a1
> "Return all records in data where :a1 is specified val"
> [data val]
> (filter
> #(= val (:a1 %)) ;filter function
> data))
>
> (defn unique-a1
> "Get set of all unique :a1 values"
> [m]
> (set (map #(:a1 %) m)))
>
> ;This is the function I am trying to write but can't get it right.
> (defn partn [data]
> (let [val-set (unique-a1 data)) ;get unique :a1 values
> ret-val {}]
> (loop [v val-set] ;loop through the unique values
> (assoc ret-val v (get-val-a1 data v))) ;build final map
> ret-val))
>
>
>
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