Handling of column names of xgb.DMatrix

Only column names are supported for xgb.DMatrix, thus setting of row names would have no effect and returned row names would be NULL.

Usage

# S3 method for class 'xgb.DMatrix'
dimnames(x)

# S3 method for class 'xgb.DMatrix'
dimnames(x) <- value

Arguments

x

Object of class xgb.DMatrix.

value

A list of two elements: the first one is ignored and the second one is column names

Details

Generic dimnames() methods are used by colnames(). Since row names are irrelevant, it is recommended to use colnames() directly.

Examples

data(agaricus.train, package = "xgboost")

train <- agaricus.train
dtrain <- xgb.DMatrix(train$data, label = train$label, nthread = 2)
dimnames(dtrain)
colnames(dtrain)
colnames(dtrain) <- make.names(1:ncol(train$data))
print(dtrain, verbose = TRUE)