Construct learners from a grid of parameters

Construct learners from a grid of parameters

learner_expand_grid(fun, args, names = TRUE, params = FALSE)

Arguments

fun

(function) A function that returns a learner.

args

(list) Parameters that generate a grid of parameters with expand.list, where the set of parameters are then passed on to fun.

names

(logical or character) If FALSE, then return a list without names. If TRUE, a named list is returned (see details).

params

(logical) If FALSE, then no information about the parameters defined by args are added to the names of the returned list.

Value

list

Examples

lrs <- learner_expand_grid(
  learner_xgboost,
  list(formula = Sepal.Length ~ ., eta = c(0.2, 0.5, 0.3))
)
lrs # use info of constructed learner as names
#> $`xgboost reg:squarederror`
#> ────────── learner object ──────────
#> xgboost reg:squarederror 
#> 
#> Estimate arguments: max_depth=2, eta=0.2, nrounds=2, subsample=1, lambda=1, verbose=0, objective=reg:squarederror 
#> Predict arguments:   
#> Formula: Sepal.Length ~ . <environment: 0x55ff0bfcc990> 
#> 
#> $`xgboost reg:squarederror.1`
#> ────────── learner object ──────────
#> xgboost reg:squarederror 
#> 
#> Estimate arguments: max_depth=2, eta=0.5, nrounds=2, subsample=1, lambda=1, verbose=0, objective=reg:squarederror 
#> Predict arguments:   
#> Formula: Sepal.Length ~ . <environment: 0x55ff0bfcc990> 
#> 
#> $`xgboost reg:squarederror.2`
#> ────────── learner object ──────────
#> xgboost reg:squarederror 
#> 
#> Estimate arguments: max_depth=2, eta=0.3, nrounds=2, subsample=1, lambda=1, verbose=0, objective=reg:squarederror 
#> Predict arguments:   
#> Formula: Sepal.Length ~ . <environment: 0x55ff0bfcc990> 
#> 

lrs <- learner_expand_grid(
  learner_xgboost,
  list(formula = Sepal.Length ~ ., eta = c(0.2, 0.5, 0.3)),
  names = "xgboost"
)
names(lrs) # use xgboost instead of info field for names
#> [1] "xgboost"   "xgboost.1" "xgboost.2"

lrs <- learner_expand_grid(
  learner_xgboost,
  list(formula = Sepal.Length ~ ., eta = c(0.2, 0.5, 0.3)),
  names = "xgboost",
  params = TRUE
)
names(lrs) # also add parameters to names
#> [1] "xgboost:Sepal.Length ~ .:0.2" "xgboost:Sepal.Length ~ .:0.5"
#> [3] "xgboost:Sepal.Length ~ .:0.3"

lrs <- learner_expand_grid(
  learner_xgboost,
  list(formula = Sepal.Length ~ ., eta = c(0.2, 0.5, 0.3)),
  names = FALSE
)
names(lrs) # unnamed list since names = FALSE
#> NULL