Create your first R Package

In you RStudio run the command:

>devtools::create("mymhipackage")

After that, a new RStudio window will show up: It will have the following structure 

Under the R folder we are going to create our file functions for instance: we want to create a function that checks wether a list of words contains at least one specific word:

let's call this function regex_check: for that we create the file: regex_check.R:

#' Regex check
#'
#' This function takes as parameter a target list of strings and a pattern
#' string and checks if one of the target strings contains the pattern
#'
#' @param target_list_string list of words
#' @param pattern
#' @return true or false
#' @export

regex_check <- function(target_list_string,pattern){
  for(k in 1:length(target_list_string))
  {
    if(grepl(pattern,target_list_string[k])[1]))
    {
      return(TRUE)
    }

  }
  return(FALSE)
}
 

Then we load these libraries:

> library(usethis)
> library(devtools)
> library(roxygen2) 

Next, we run the document method, which will generate the associated documentation under the folder man:

>document()

the new folder Structure of the packge will look like that:

After all, if we want to test our package we have to load and install it:

> devtools::load_all()

> devtools::install()

That's it ;-) we can go back to the main project:

and run :

>library(mymhipackage) # in order to load your first library

Finally last tip: if you want to unload the library because you want to modify something in it, then run the following comand:

>detach("package:mymhipackage", unload=TRUE)