Only column names are supported for xgb.DMatrix, thus setting of
row names would have no effect and returned row names would be NULL.
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)
#> [[1]]
#> NULL
#>
#> [[2]]
#> [1] "cap-shape=bell" "cap-shape=conical"
#> [3] "cap-shape=convex" "cap-shape=flat"
#> [5] "cap-shape=knobbed" "cap-shape=sunken"
#> [7] "cap-surface=fibrous" "cap-surface=grooves"
#> [9] "cap-surface=scaly" "cap-surface=smooth"
#> [11] "cap-color=brown" "cap-color=buff"
#> [13] "cap-color=cinnamon" "cap-color=gray"
#> [15] "cap-color=green" "cap-color=pink"
#> [17] "cap-color=purple" "cap-color=red"
#> [19] "cap-color=white" "cap-color=yellow"
#> [21] "bruises?=bruises" "bruises?=no"
#> [23] "odor=almond" "odor=anise"
#> [25] "odor=creosote" "odor=fishy"
#> [27] "odor=foul" "odor=musty"
#> [29] "odor=none" "odor=pungent"
#> [31] "odor=spicy" "gill-attachment=attached"
#> [33] "gill-attachment=descending" "gill-attachment=free"
#> [35] "gill-attachment=notched" "gill-spacing=close"
#> [37] "gill-spacing=crowded" "gill-spacing=distant"
#> [39] "gill-size=broad" "gill-size=narrow"
#> [41] "gill-color=black" "gill-color=brown"
#> [43] "gill-color=buff" "gill-color=chocolate"
#> [45] "gill-color=gray" "gill-color=green"
#> [47] "gill-color=orange" "gill-color=pink"
#> [49] "gill-color=purple" "gill-color=red"
#> [51] "gill-color=white" "gill-color=yellow"
#> [53] "stalk-shape=enlarging" "stalk-shape=tapering"
#> [55] "stalk-root=bulbous" "stalk-root=club"
#> [57] "stalk-root=cup" "stalk-root=equal"
#> [59] "stalk-root=rhizomorphs" "stalk-root=rooted"
#> [61] "stalk-root=missing" "stalk-surface-above-ring=fibrous"
#> [63] "stalk-surface-above-ring=scaly" "stalk-surface-above-ring=silky"
#> [65] "stalk-surface-above-ring=smooth" "stalk-surface-below-ring=fibrous"
#> [67] "stalk-surface-below-ring=scaly" "stalk-surface-below-ring=silky"
#> [69] "stalk-surface-below-ring=smooth" "stalk-color-above-ring=brown"
#> [71] "stalk-color-above-ring=buff" "stalk-color-above-ring=cinnamon"
#> [73] "stalk-color-above-ring=gray" "stalk-color-above-ring=orange"
#> [75] "stalk-color-above-ring=pink" "stalk-color-above-ring=red"
#> [77] "stalk-color-above-ring=white" "stalk-color-above-ring=yellow"
#> [79] "stalk-color-below-ring=brown" "stalk-color-below-ring=buff"
#> [81] "stalk-color-below-ring=cinnamon" "stalk-color-below-ring=gray"
#> [83] "stalk-color-below-ring=orange" "stalk-color-below-ring=pink"
#> [85] "stalk-color-below-ring=red" "stalk-color-below-ring=white"
#> [87] "stalk-color-below-ring=yellow" "veil-type=partial"
#> [89] "veil-type=universal" "veil-color=brown"
#> [91] "veil-color=orange" "veil-color=white"
#> [93] "veil-color=yellow" "ring-number=none"
#> [95] "ring-number=one" "ring-number=two"
#> [97] "ring-type=cobwebby" "ring-type=evanescent"
#> [99] "ring-type=flaring" "ring-type=large"
#> [101] "ring-type=none" "ring-type=pendant"
#> [103] "ring-type=sheathing" "ring-type=zone"
#> [105] "spore-print-color=black" "spore-print-color=brown"
#> [107] "spore-print-color=buff" "spore-print-color=chocolate"
#> [109] "spore-print-color=green" "spore-print-color=orange"
#> [111] "spore-print-color=purple" "spore-print-color=white"
#> [113] "spore-print-color=yellow" "population=abundant"
#> [115] "population=clustered" "population=numerous"
#> [117] "population=scattered" "population=several"
#> [119] "population=solitary" "habitat=grasses"
#> [121] "habitat=leaves" "habitat=meadows"
#> [123] "habitat=paths" "habitat=urban"
#> [125] "habitat=waste" "habitat=woods"
#>
colnames(dtrain)
#> [1] "cap-shape=bell" "cap-shape=conical"
#> [3] "cap-shape=convex" "cap-shape=flat"
#> [5] "cap-shape=knobbed" "cap-shape=sunken"
#> [7] "cap-surface=fibrous" "cap-surface=grooves"
#> [9] "cap-surface=scaly" "cap-surface=smooth"
#> [11] "cap-color=brown" "cap-color=buff"
#> [13] "cap-color=cinnamon" "cap-color=gray"
#> [15] "cap-color=green" "cap-color=pink"
#> [17] "cap-color=purple" "cap-color=red"
#> [19] "cap-color=white" "cap-color=yellow"
#> [21] "bruises?=bruises" "bruises?=no"
#> [23] "odor=almond" "odor=anise"
#> [25] "odor=creosote" "odor=fishy"
#> [27] "odor=foul" "odor=musty"
#> [29] "odor=none" "odor=pungent"
#> [31] "odor=spicy" "gill-attachment=attached"
#> [33] "gill-attachment=descending" "gill-attachment=free"
#> [35] "gill-attachment=notched" "gill-spacing=close"
#> [37] "gill-spacing=crowded" "gill-spacing=distant"
#> [39] "gill-size=broad" "gill-size=narrow"
#> [41] "gill-color=black" "gill-color=brown"
#> [43] "gill-color=buff" "gill-color=chocolate"
#> [45] "gill-color=gray" "gill-color=green"
#> [47] "gill-color=orange" "gill-color=pink"
#> [49] "gill-color=purple" "gill-color=red"
#> [51] "gill-color=white" "gill-color=yellow"
#> [53] "stalk-shape=enlarging" "stalk-shape=tapering"
#> [55] "stalk-root=bulbous" "stalk-root=club"
#> [57] "stalk-root=cup" "stalk-root=equal"
#> [59] "stalk-root=rhizomorphs" "stalk-root=rooted"
#> [61] "stalk-root=missing" "stalk-surface-above-ring=fibrous"
#> [63] "stalk-surface-above-ring=scaly" "stalk-surface-above-ring=silky"
#> [65] "stalk-surface-above-ring=smooth" "stalk-surface-below-ring=fibrous"
#> [67] "stalk-surface-below-ring=scaly" "stalk-surface-below-ring=silky"
#> [69] "stalk-surface-below-ring=smooth" "stalk-color-above-ring=brown"
#> [71] "stalk-color-above-ring=buff" "stalk-color-above-ring=cinnamon"
#> [73] "stalk-color-above-ring=gray" "stalk-color-above-ring=orange"
#> [75] "stalk-color-above-ring=pink" "stalk-color-above-ring=red"
#> [77] "stalk-color-above-ring=white" "stalk-color-above-ring=yellow"
#> [79] "stalk-color-below-ring=brown" "stalk-color-below-ring=buff"
#> [81] "stalk-color-below-ring=cinnamon" "stalk-color-below-ring=gray"
#> [83] "stalk-color-below-ring=orange" "stalk-color-below-ring=pink"
#> [85] "stalk-color-below-ring=red" "stalk-color-below-ring=white"
#> [87] "stalk-color-below-ring=yellow" "veil-type=partial"
#> [89] "veil-type=universal" "veil-color=brown"
#> [91] "veil-color=orange" "veil-color=white"
#> [93] "veil-color=yellow" "ring-number=none"
#> [95] "ring-number=one" "ring-number=two"
#> [97] "ring-type=cobwebby" "ring-type=evanescent"
#> [99] "ring-type=flaring" "ring-type=large"
#> [101] "ring-type=none" "ring-type=pendant"
#> [103] "ring-type=sheathing" "ring-type=zone"
#> [105] "spore-print-color=black" "spore-print-color=brown"
#> [107] "spore-print-color=buff" "spore-print-color=chocolate"
#> [109] "spore-print-color=green" "spore-print-color=orange"
#> [111] "spore-print-color=purple" "spore-print-color=white"
#> [113] "spore-print-color=yellow" "population=abundant"
#> [115] "population=clustered" "population=numerous"
#> [117] "population=scattered" "population=several"
#> [119] "population=solitary" "habitat=grasses"
#> [121] "habitat=leaves" "habitat=meadows"
#> [123] "habitat=paths" "habitat=urban"
#> [125] "habitat=waste" "habitat=woods"
colnames(dtrain) <- make.names(1:ncol(train$data))
print(dtrain, verbose = TRUE)
#> xgb.DMatrix dim: 6513 x 126 info: label colnames:
#> 'X1','X2','X3','X4','X5','X6','X7','X8','X9','X10','X11','X12','X13','X14','X15','X16','X17','X18','X19','X20','X21','X22','X23','X24','X25','X26','X27','X28','X29','X30','X31','X32','X33','X34','X35','X36','X37','X38','X39','X40','X41','X42','X43','X44','X45','X46','X47','X48','X49','X50','X51','X52','X53','X54','X55','X56','X57','X58','X59','X60','X61','X62','X63','X64','X65','X66','X67','X68','X69','X70','X71','X72','X73','X74','X75','X76','X77','X78','X79','X80','X81','X82','X83','X84','X85','X86','X87','X88','X89','X90','X91','X92','X93','X94','X95','X96','X97','X98','X99','X100','X101','X102','X103','X104','X105','X106','X107','X108','X109','X110','X111','X112','X113','X114','X115','X116','X117','X118','X119','X120','X121','X122','X123','X124','X125','X126'