Fix merging of lists (#18)

R/utils.R

@@ -390,12 +390,23 @@
 # data.frame
 #' @importFrom dplyr full_join
 .full_join_list <- function(res){
-    df <- Reduce(function(df1, df2){
-        # Get common columns
-        common_cols <- intersect(colnames(df1), colnames(df2))
-        # Merge based on common columns
-        temp <- full_join(df1, df2, by = common_cols)
-        return(temp)
-    }, res)
+    # Remove empty elements
+    res <- res[ lengths(res) > 0 ]
+    # If there is more than one element, merge them
+    if( length(res) > 1 ){
+        df <- Reduce(function(df1, df2){
+            # Get common columns
+            common_cols <- intersect(colnames(df1), colnames(df2))
+            # Merge based on common columns
+            temp <- full_join(df1, df2, by = common_cols)
+            return(temp)
+        }, res)
+    } else if( length(res) == 1 ){
+        # Otherwise if there is only one element, give the element
+        df <- res[[1]]
+    } else{
+        # If all the data.frames were without information, give NULL
+        df <- NULL
+    }
     return(df)
 }