Accessors for serializable attributes of a model.
These methods allow to manipulate the key-value attribute strings of an xgboost model.
xgb.attr(object, name) xgb.attr(object, name) <- value xgb.attributes(object) xgb.attributes(object) <- value
object |
Object of class |
name |
a non-empty character string specifying which attribute is to be accessed. |
value |
a value of an attribute for |
The primary purpose of xgboost model attributes is to store some meta-data about the model.
Note that they are a separate concept from the object attributes in R.
Specifically, they refer to key-value strings that can be attached to an xgboost model,
stored together with the model's binary representation, and accessed later
(from R or any other interface).
In contrast, any R-attribute assigned to an R-object of xgb.Booster class
would not be saved by xgb.save because an xgboost model is an external memory object
and its serialization is handled externally.
Also, setting an attribute that has the same name as one of xgboost's parameters wouldn't
change the value of that parameter for a model.
Use xgb.parameters<- to set or change model parameters.
The attribute setters would usually work more efficiently for xgb.Booster.handle
than for xgb.Booster, since only just a handle (pointer) would need to be copied.
That would only matter if attributes need to be set many times.
Note, however, that when feeding a handle of an xgb.Booster object to the attribute setters,
the raw model cache of an xgb.Booster object would not be automatically updated,
and it would be user's responsibility to call xgb.serialize to update it.
The xgb.attributes<- setter either updates the existing or adds one or several attributes,
but it doesn't delete the other existing attributes.
xgb.attr returns either a string value of an attribute
or NULL if an attribute wasn't stored in a model.
xgb.attributes returns a list of all attribute stored in a model
or NULL if a model has no stored attributes.
data(agaricus.train, package='xgboost')
train <- agaricus.train
bst <- xgboost(data = train$data, label = train$label, max_depth = 2,
eta = 1, nthread = 2, nrounds = 2, objective = "binary:logistic")
xgb.attr(bst, "my_attribute") <- "my attribute value"
print(xgb.attr(bst, "my_attribute"))
xgb.attributes(bst) <- list(a = 123, b = "abc")
xgb.save(bst, 'xgb.model')
bst1 <- xgb.load('xgb.model')
if (file.exists('xgb.model')) file.remove('xgb.model')
print(xgb.attr(bst1, "my_attribute"))
print(xgb.attributes(bst1))
# deletion:
xgb.attr(bst1, "my_attribute") <- NULL
print(xgb.attributes(bst1))
xgb.attributes(bst1) <- list(a = NULL, b = NULL)
print(xgb.attributes(bst1))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.