code: public static double euclidean(AssociativeArray a1, AssociativeArray a2) {
          Map<Object, Double> columnDistances = columnDistances(a1, a2, null);
          
          double distance = 0.0;
          for(double columnDistance : columnDistances.values()) {
              distance+=(columnDistance*columnDistance);
          }
          
          return Math.sqrt(distance);
      }
docs: Estimates the euclidean distance of two Associative Arrays.
  
  @param a1
  @param a2
  @return