Read Objects Based on Parameter List

Reads R objects from specified folders based on a generated hash of the provided parameters_list.

Usage

read_objects(
  folders,
  parameters_list,
  hash_includes_timestamp = FALSE,
  ignore_script_name = FALSE,
  ignore_na = TRUE,
  alphabetical_order = TRUE,
  algo = "xxhash64",
  print_hash = FALSE,
  tagging_file_name = "indexr_tagging.txt",
  silent = FALSE
)

Arguments

folders

Character vector specifying the paths to directories containing the saved objects. The function will check each folder in order to find the file.

parameters_list

A named list of arguments used to generate a unique hash for the file.

hash_includes_timestamp

Logical. If TRUE, the timestamp is included in the hash generation.

ignore_script_name

Logical. If TRUE, the script name is ignored during hash generation.

ignore_na

Logical. If TRUE, NA values in parameters_list are ignored during hash generation.

alphabetical_order

Logical. If TRUE, the names in parameters_list are sorted alphabetically before hash generation.

algo

Character string specifying the hashing algorithm to use. Default is "xxhash64".

print_hash

Logical. If TRUE, prints the generated hash. This is helpful for debugging.

tagging_file_name

Character string of a txt file that is being used for tagging results. See ?start_tagging.

silent

Logical. If TRUE, no check is done that pairs of results files (parameters and associated results) is done. This check is not necessary, but done by default to keep the user aware of a scenario that usually results from manual file manipulation.

Value

The data stored in the file retrieved, typically the results. Returns NULL if the file is not found in any of the specified folders.

Details

This function attempts to read an R object from files located in one of the specified folders. The file name is based on the hash of the provided arguments. If the object is successfully read and a tagging files exists and is specified, the function appends the hash and the current timestamp to the tagging file in the folder where the file was found.

See also

save_objects()

Examples

## Setup
tmp_dir <- file.path(tempdir(), "example")
dir.create(tmp_dir)

## Example using parameter list to run simulation and save results
parameters_list <- list(
  iterations = 1000,
  x_dist = "rnorm",
  x_dist_options = list(n = 10, mean = 1, sd = 2),
  error_dist = "rnorm",
  error_dist_options = list(n = 10, mean = 0, sd = 1),
  beta0 = 1,
  beta1 = 1
)

betas <- numeric(parameters_list$iterations)
for (i in 1:parameters_list$iterations) {
  x <- do.call(parameters_list$x_dist, parameters_list$x_dist_options)
  err <- do.call(parameters_list$error_dist, parameters_list$error_dist_options)
  y <- parameters_list$beta0 + parameters_list$beta1*x + err
  betas[i] <- coef(lm(y ~ x))["x"]
}

save_objects(folder = tmp_dir, results = betas, parameters_list = parameters_list)

## Read back in (consider clearing environment before running)
## Re-setup
tmp_dir <- file.path(tempdir(), "example")

parameters_list <- list(
  iterations = 1000,
  x_dist = "rnorm",
  x_dist_options = list(n = 10, mean = 1, sd = 2),
  error_dist = "rnorm",
  error_dist_options = list(n = 10, mean = 0, sd = 1),
  beta0 = 1,
  beta1 = 1
)

betas <- read_objects(folder = tmp_dir, parameters_list = parameters_list)
#> Warning: File not found for hash: 8fe7c7435185d35c

## Cleanup
unlink(tmp_dir, recursive = TRUE)