September 2017 Update

Task/Benfords-law/Clojure/benfords-law.clj

@@ -0,0 +1,73 @@
+(ns example
+  (:gen-class))
+
+(defn abs [x]
+  (if (> x 0)
+    x
+    (- x)))
+
+(defn calc-benford-stats [digits]
+  " Frequencies of digits in data "
+  (let [y (frequencies digits)
+         tot (reduce + (vals y))]
+    [y tot]))
+
+(defn show-benford-stats [v]
+  " Prints in percent the actual, Benford expected, and difference"
+  (let [fd (map (comp first str) v)]        ; first digit of each record
+    (doseq [q (range 1 10)
+            :let [[y tot] (calc-benford-stats fd)
+                  d (first (str q))         ; reference digit
+                  f (/ (get y d 0) tot 0.01)  ; percent of occurence of digit
+                  p (* (Math/log10 (/ (inc q) q)) 100)  ; Benford expected percent
+                  e (abs (- f p))]]                     ; error (difference)
+      (println (format "%3d %10.2f %10.2f %10.2f"
+                       q
+                       f
+                       p
+                       e)))))
+
+; Generate fibonacci results
+(def fib (lazy-cat [0N 1N] (map + fib (rest fib))))
+
+;(def fib-digits (map (comp first str) (take 10000 fib)))
+(def fib-digits (take 10000 fib))
+(def header "         found-%    expected-%  diff")
+
+(println "Fibonacci Results")
+(println header)
+(show-benford-stats fib-digits)
+;
+; Universal Constants from Physics (using first column of data)
+(println "Universal Constants from Physics")
+(println header)
+(let [
+      data-parser (fn [s]
+                  (let [x (re-find #"\s{10}-?[0|/\.]*([1-9])" s)]
+                    (if (not (nil? x))    ; Skips records without number
+                      (second x)
+                      x)))
+
+      input (slurp "http://physics.nist.gov/cuu/Constants/Table/allascii.txt")
+
+      y (for [line (line-seq (java.io.BufferedReader.
+                               (java.io.StringReader. input)))]
+          (data-parser line))
+      z (filter identity y)]
+  (show-benford-stats z))
+
+; Sunspots
+(println "Sunspots average count per month since 1749")
+(println header)
+(let [
+      data-parser (fn [s]
+                  (nth (re-find #"(.+?\s){3}([1-9])" s) 2))
+
+      ; Sunspot data loaded from file (saved from ;https://solarscience.msfc.nasa.gov/greenwch/SN_m_tot_V2.0.txt")
+      ; (note: attempting to load directly from url causes https Trust issues, so saved to file after loading to Browser)
+      input (slurp "SN_m_tot_V2.0.txt")
+      y (for [line (line-seq (java.io.BufferedReader.
+                               (java.io.StringReader. input)))]
+          (data-parser line))]
+
+  (show-benford-stats y))