wsrf (version 1.5.47)

subset.wsrf: Subset of a Forest

Description

Obtain a subset of a forest.

Usage

"subset"(x, trees, ...)

Arguments

x

an object of class wsrf.

trees

Which trees should be included in the sub-forest. An integer vector, which indicates the index of the trees.

...

not used.

Value

An object of class wsrf.

See Also

combine

Examples

  library("wsrf")

  # Prepare parameters.
  ds     <- rattle::weather
  target <- "RainTomorrow"
  vars   <- setdiff(names(ds), c("Date", "Location", "RISK_MM"))
  if (sum(is.na(ds[vars]))) ds[vars] <- randomForest::na.roughfix(ds[vars])
  ds[target] <- as.factor(ds[[target]])
  form <- as.formula(paste(target, "~ ."))
  set.seed(42)
  train <- sample(nrow(ds), 0.7*nrow(ds))
  test  <- setdiff(seq_len(nrow(ds)), train)
  
  # Build model.
  model.wsrf <- wsrf(form, data=ds[train, vars])
  print(model.wsrf)
  
  # Subset.
  submodel.wsrf <- subset.wsrf(model.wsrf, 1:200)
  print(submodel.wsrf)
  cl <- predict(submodel.wsrf, newdata=ds[test, vars], type="response")
  actual <- ds[test, target]
  (accuracy.wsrf <- sum(cl==actual)/length(actual))