diff --git a/R/ggheatmap.R b/R/ggheatmap.R
index 11cd698..55af49c 100644
--- a/R/ggheatmap.R
+++ b/R/ggheatmap.R
@@ -1,4 +1,5 @@
 ggheatmap<-function(df, x=NULL, y=NULL, value=NULL){
+
   if (is.null(x)){x=colnames(df)[1]}
   if (is.null(y)){y=colnames(df)[2]}
   if (is.null(value)){value=colnames(df)[3]}
@@ -6,7 +7,7 @@ ggheatmap<-function(df, x=NULL, y=NULL, value=NULL){
   order<-clustsort(df %>% spread(y,value))
 
   df %>%
-    ggplot(aes(df[,x], df[,y], fill=df[,value]))+
+    ggplot(aes_string(x, y, fill=value))+
     scale_x_discrete(limits=order$x)+
     scale_y_discrete(limits=order$y)+
     labs(x=x, y=y)+