From 5188bad8733e578fe9849fbd2ae89e9aee4bc1bc Mon Sep 17 00:00:00 2001
From: hetong007 <hetong007@gmail.com>
Date: Sun, 25 Jan 2015 14:16:46 -0800
Subject: [PATCH] fix cv attr

---
 R-package/R/slice.xgb.DMatrix.R | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/R-package/R/slice.xgb.DMatrix.R b/R-package/R/slice.xgb.DMatrix.R
index 419170a66..b70a8ee92 100644
--- a/R-package/R/slice.xgb.DMatrix.R
+++ b/R-package/R/slice.xgb.DMatrix.R
@@ -28,6 +28,18 @@ setMethod("slice", signature = "xgb.DMatrix",
               if (class(object) != "xgb.DMatrix") {
                   stop("slice: first argument dtrain must be xgb.DMatrix")
               }
-              ret <- .Call("XGDMatrixSliceDMatrix_R", object, idxset, PACKAGE = "xgboost")
+              ret <- .Call("XGDMatrixSliceDMatrix_R", object, idxset, 
+                           PACKAGE = "xgboost")
+              
+              attr_list <- attributes(object)
+              nr <- xgb.numrow(object)
+              len <- sapply(attr_list,length)
+              ind <- which(len==nr)
+              if (length(ind)>0) {
+                  nms <- names(attr_list)[ind]
+                  for (i in 1:length(ind)) {
+                    attr(ret,nms[i]) <- attr(object,nms[i])[idxset]
+                  }
+              }
               return(structure(ret, class = "xgb.DMatrix"))
           })