clj-statistics-fns
A simple Clojure library for calculating some common statistics of data sets: minimum, maximum, average, median and k-th percentile.
Usage
First, install by adding to your dependencies array:
[mnylen/clj-statistics-fns "0.1.0"]
Supported operations:
(require '[clj-statistics-fns.core :as s])
(s/average [1 2 3])
;; => 2
(s/median [1 2 3])
;; => 2
(s/kth-percentile 95 (range 0 101))
;; => 95
(s/minimum [1 2 3])
;; => 1
(s/maximum [1 2 3])
;; => 3
Collecting values
All functions in the clj-statistics-fns.core namespace accept normal Clojure collections, so you can just collect the values into a vector. However, clj-statistics-fns also comes with an memory optimized data structure more suited for collecting a lot of values falling within some finite range. If your data set has a lot of duplicate values, you should use the optimized data structure instead.
Sample use & supported operations:
(require '[clj-statistics-fns.sorted-values :as v])
;; create
(v/sorted-values 1 2 3)
;; => #object[clj_statistics_fns.sorted_values.SortedValues 0x77b707a SortedValues{1 1, 2 1, 3 1}]
(v/wrap [1 2 3])
;; => #object[clj_statistics_fns.sorted_values.SortedValues 0x56aa6084 SortedValues{1 1, 2 1, 3 1}]
;; add value
(v/add-value (v/sorted-values 1 2 3) 2)
;; => #object[clj_statistics_fns.sorted_values.SortedValues 0x407d4167 SortedValues{1 1, 2 2, 3 1}]
;; get frequency of a value
(v/frequency (v/sorted-values 3 2 1 2) 2)
;; => 2
;; count, nth
(count (v/sorted-values 1 2 3))
;; => 3
(nth (v/sorted-values 3 1 2) 0)
;; => 1
(let [values (v/sorted-values 2 1 3 1 2 3)]
(map #(nth values %) (range (count values))))
;; => (1 1 2 2 3 3)
With these, you could implement ring middleware for collecting response times:
(require '[clj-statistics-fns.sorted-values :as v])
;; ring middleware for collecting response times:
(def ^:private response-times
(atom (v/sorted-values)))
(defn collect-repsonse-times [handler]
(fn [request]
(let [start-time (System/currentTimeMillis)
response (handler request)
end-time (System/currentTimeMillis)
response-time (- end-time start-time)]
(swap! response-times v/add-value response-time)
response))))
Then, somewhere else:
(require '[clj-statistics-fns.core :as s])
(s/median @response-times)
(s/average @response-times)
(s/kth-percentile 95 @response-times)
License
Copyright © 2018 Mikko Nylén
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.