Extention of [blockrand::blockrand]

blockrand2.R

#' Extention de [blockrand::blockrand]
#'
#' @param n_arm nombre de patient par bras
#' @param levels vecteur de bras de traitement
#' @param strata liste contenant les facteurs de stratification
#' @param block.sizes tailles de bloc possible (multiple du nombre de bras)
#' @param ... passé à [blockrand::blockrand]
#'
#' @author Dan Chaltiel (30/06/2023)
#' @return une tibble
#'
#' @examples
blockrand2 = function(n_arm, levels, strata, block.sizes = c(2,4,6), ...){
  rlang::check_installed("blockrand")
  wrong = block.sizes%%length(levels)!=0
  if(any(wrong)){
    cli::cli_abort(c(
      "Some {.arg block.sizes} are not divisible by the number of treatment levels",
      i="There are {.val {length(levels)}} treatment levels: {.val {levels}}",
      i="{.arg block.sizes} {.val {block.sizes[wrong]}} {cli::qty(sum(wrong))} {?is/are} not
         divisible by {.val {length(levels)}}"
    ))
  }
  expand.grid(strata) %>%
    unite("strata", everything(), sep="__") %>%
    pull(strata) %>%
    map(~{
      blockrand::blockrand(n = n_arm,
                           levels = levels,
                           stratum = .x,
                           id.prefix = paste(.x, " - "),
                           block.sizes = block.sizes/length(levels), ...)
    }) %>%
    list_rbind() %>%
    separate(stratum, into=names(strata), sep="__") %>%
    mutate(id = as.character(id)) %>%
    as_tibble()
}


# Exemple 1 -----------------------------------------------------------------------------------
# autre exemple sur https://bookdown.org/pdr_higgins/rmrwr/randomization-for-clinical-trials-with-r.html


library(tidyverse)

set.seed(42)
strat = list(age=c("<=18", ">18"),
             stage=c("I", "II", "III"),
             country=c("group1", "group2", "group3"))
rando = blockrand2(n_arm=150, levels=c("SOC", "SOC+exp"),
                   strata=strat, block.sizes = c(4, 8))

cli::cli_inform("Calculating stratified randomisation for {prod(lengths(strat))} strata.")

print(rando)

rando %>%
  select(all_of(names(strat)), treatment) %>%
  mutate(across(everything(), ~as.numeric(factor(.x)))) %>%
  write.csv2("rando.csv")