Convert a list of boot objects to a tidy dataframe

This function converts a named list of "boot" objects (typically produced by bootstrap_cube() into a single long-format dataframe. Each element of the list is assumed to correspond to one group, with the list names defining the values of the grouping variable.

Usage

boot_list_to_dataframe(boot_list, grouping_var)

Arguments

boot_list

A named list of objects of class "boot", as returned by boot::boot(). Each list element must correspond to exactly one group, and the list names are used as the values of the grouping variable.

grouping_var

A character string giving the name of the grouping variable (e.g. "year"). This will be used as the column name in the returned dataframe.

Value

A dataframe with the following columns:

• sample: Sample ID of the bootstrap replicate

• est_original: The statistic based on the full dataset per group

• rep_boot: The statistic based on a bootstrapped dataset (bootstrap replicate)

• est_boot: The bootstrap estimate (mean of bootstrap replicates per group)

• se_boot: The standard error of the bootstrap estimate (standard deviation of the bootstrap replicates per group)

• bias_boot: The bias of the bootstrap estimate per group

Details

This function is primarily intended for use with bootstrapping using the bootstrap_cube() function generated with boot methods.

The function assumes that each boot object in boot_list contains a single bootstrap statistic per replicate (i.e. boot$t is a vector or a one-column matrix).

See also

Other indicator_uncertainty_helper: bootstrap_cube_raw(), calculate_boot_ci_from_boot(), derive_bootstrap_method(), resolve_bootstrap_method()

Examples

if (FALSE) { # \dontrun{
# After processing a data cube with b3gbi::process_cube()

# Function to calculate statistic of interest
# Mean observations per year
mean_obs <- function(x) {
  out_df <- aggregate(obs ~ year, x, mean) # Calculate mean obs per year
  names(out_df) <- c("year", "diversity_val") # Rename columns
  return(out_df)
}
mean_obs(processed_cube$data)

# Perform bootstrapping
bootstrap_mean_obs <- bootstrap_cube(
  data_cube = processed_cube,
  fun = mean_obs,
  grouping_var = "year",
  samples = 1000,
  method = "boot_group_specific",
  seed = 123
)

bootstrap_df <- boot_list_to_dataframe(
  boot_list = bootstrap_mean_obs,
  grouping_var = "year"
)

head(bootstrap_df)
} # }