lib/genevalidator/ext/array.rb in genevalidator-1.6.12 vs lib/genevalidator/ext/array.rb in genevalidator-2.1.3

@@ -7,28 +7,45 @@
 
     def mean
       sum / length.to_f
     end
 
-    def median
-      sorted = sort
+    def median(already_sorted = false)
+      sorted = already_sorted ? self : sort
       len    = sorted.length
       (sorted[(len - 1) / 2] + sorted[len / 2]) / 2.0
     end
 
     def mode
-      freq = inject(Hash.new(0)) { |h, v| h[v] += 1; h }
-      sort_by { |v| freq[v] }.last
+      freq = each_with_object(Hash.new(0)) { |v, h| h[v] += 1; }
+      max_by { |v| freq[v] }
     end
 
     def sample_variance
       m   = mean
       sum = inject(0) { |accum, i| accum + (i - m)**2 }
       sum / (length - 1).to_f
     end
 
     def standard_deviation
       Math.sqrt(sample_variance)
+    end
+
+    def all_quartiles
+      sorted = sort
+      len    = sorted.length
+      split  = sorted.median_split
+      [
+        split[0].median(true),
+        sorted.median(true),
+        split[1].median(true)
+      ]
+    end
+
+    def median_split
+      len    = length
+      center = len % 2
+      [self[0..len / 2 - 1], self[len / 2 + center..-1]]
     end
   end
 end
 
 class Array