R/melt_aorsf.R

In aorsf: Accelerated Oblique Random Survival Forests

# need to make this to avoid possible memory leak in data.table melt

melt_aorsf <-
 function(data,
          id.vars,
          measure.vars,
          variable.name = "variable",
          value.name = "value") {
  if (!is.data.frame(data)) {
   stop("Input 'data' must be a data frame.")
  }

  if (!is.character(id.vars)) {
   stop("Input 'id.vars' must be a character vector.")
  }

  if (!is.character(measure.vars)) {
   stop("Input 'measure.vars' must be a character vector.")
  }

  # Select id variables and measure variables
  id_data <- data[id.vars]
  measure_data <- data[measure.vars]

  # Create a sequence variable to represent the variable names
  variable_data <- rep(names(measure_data), each = nrow(data))

  # Reshape the data
  long_data <- data.frame(id_data,
                          variable = variable_data,
                          value = unlist(measure_data, use.names = FALSE))

  names(long_data)[names(long_data) == 'variable'] <- variable.name
  names(long_data)[names(long_data) == 'value'] <- value.name

  return(long_data)
 }