lib/counter: Added pack function

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/counter.nit b/lib/counter.nit
index 9a539e6..ceecb48 100644 (file)
--- a/lib/counter.nit
+++ b/lib/counter.nit
@@ -280,6 +280,37 @@ class Counter[E]
                        printn("* ", i or else "null", " = ", self[i], " => occurences ", self[i].to_f / sum.to_f * 100.0, "%, cumulative ", subtotal.to_f / sum.to_f * 100.0, "% \n")
                end
        end
+
+       # Packs elements into separate arrays based on their occurences
+       #
+       # ~~~nit
+       #       var x = "aaaabbbeeecccddhhgjt"
+       #       var c = new Counter[Char]
+       #       for i in x do c.inc i
+       #       var ret = c.pack
+       #       assert ret.join(", ") == """[t,g,j], [d,h], [c,b,e], [a]"""
+       # ~~~
+       fun pack: Array[Array[E]] do
+               var ret = new Array[Array[E]]
+               var base = self.sort
+               if base.is_empty then return ret
+               var curr = new Array[E]
+               curr.push base.first
+               var curr_score = self[base.first]
+               base.shift
+               for i in base do
+                       if self[i] == curr_score then
+                               curr.push i
+                               continue
+                       end
+                       curr_score = self[i]
+                       ret.push curr
+                       curr = new Array[E]
+                       curr.push i
+               end
+               if not curr.is_empty then ret.push curr
+               return ret
+       end
 end
 
 redef class Collection[E]