fix print.xgb.DMatrix doc

R-package/R/xgb.DMatrix.R

@@ -327,11 +327,20 @@ slice.xgb.DMatrix <- function(object, idxset, ...) {
 
 #' Print xgb.DMatrix
 #' 
-#' Print information about an xgb.DMatrix. 
+#' Print information about xgb.DMatrix. 
-#' Currently is would display 
+#' Currently it displays dimensions and presence of info-fields and colnames.
+#' 
 #' @param x an xgb.DMatrix object
 #' @param verbose whether to print colnames (when present)
 #' 
+#' 
+#' @examples
+#' data(agaricus.train, package='xgboost')
+#' train <- agaricus.train
+#' dtrain <- xgb.DMatrix(train$data, label=train$label)
+#' 
+#' dtrain
+#' print(dtrain, verbose=T)
 #' @export
 print.xgb.DMatrix <- function(x, verbose=FALSE, ...) {
   cat('xgb.DMatrix  dim:', nrow(x), 'x', ncol(x), ' info: ')

R-package/man/print.xgb.DMatrix.Rd

@@ -12,7 +12,15 @@ print.xgb.DMatrix(x, verbose = FALSE, ...)
 \item{verbose}{whether to print colnames (when present)}
 }
 \description{
-Print information about an xgb.DMatrix. 
+Print information about xgb.DMatrix. 
-Currently is would display
+Currently it displays dimensions and presence of info-fields and colnames.
+}
+\examples{
+data(agaricus.train, package='xgboost')
+train <- agaricus.train
+dtrain <- xgb.DMatrix(train$data, label=train$label)
+
+dtrain
+print(dtrain, verbose=T)
 }
 

R-package/man/xgb.DMatrix.Rd

@@ -18,7 +18,7 @@ value that represents missing value. Sometime a data use 0 or other extreme valu
 }
 \description{
 Contruct xgb.DMatrix object from dense matrix, sparse matrix 
-or local file (that is a previously saved \code{xgb.DMatrix}).
+or local file (that was created previously by saving an \code{xgb.DMatrix}).
 }
 \examples{
 data(agaricus.train, package='xgboost')