diff --git a/ext/ml.js b/ext/ml.js
old mode 100644
new mode 100755
index 6fd4902..96088a5
--- a/ext/ml.js
+++ b/ext/ml.js
@@ -30,13 +30,14 @@ jx.ml.mapreduce = function(data,fn_map,fn_reduce){
 		}
 		__map[id].push(mvalue) ;
 	}//-- end of the emitter
+	
 	if(data.constructor != Array){
-		jx.utils.patterns.visitor(data,function(id){
+		jx.utils.patterns.visitor(jx.utils.keys(data),function(id){	
 			fn_map(data[id],emit) ;
 		});
 	}else{
-		jx.utils.patterns.visitor(data,function(i){
-			fn_map(data[i],emit) ;
+		jx.utils.patterns.visitor(data,function(row){
+			fn_map(row,emit) ;
 		});
 	}
 
diff --git a/utils.js b/utils.js
old mode 100644
new mode 100755
index 61a7313..ac0f669
--- a/utils.js
+++ b/utils.js
@@ -54,13 +54,8 @@ jx.utils.vector=function(key,rec){
 * Extract keys from an associative array
 * @param rec	associative array
 */
-jx.utils.keys=function(rec){
-	var keys = [] ;
-	for(var id in rec){
-            
-		keys.push(id) ;
-	}
-	return keys ;
+jx.utils.keys=function(rec){	
+	return Object.keys(rec) ;
 }//-- end jx.utils.keys
 jx.utils.values = function(rec){
 	var r = []