9 Adding Functions and Data

In this chapter, we will integrate the functions and example dataset that we previously created into our package using the use_r() approach provided by the usethis package.

9.1 Adding Functions

To add the functions to our package, we will first create an R script file for each function. We can use the use_r() function to automate this process. This function creates a new R script file in the R/ directory of our package.


Please see visual guides below:


# Adding the random movie recommendation function
usethis::use_r("random_movie_recommendation.R")



# Adding the calculate group mean function
usethis::use_r("calculate_group_mean.R")



9.2 Adding Example Data

Similarly, we can add the example dataset to our package by creating an R script file containing the dataset. It is generally a good idea to save the original script that creates your example dataset. This script should be placed in a folder called “data-raw”. You certainly want that folder and script in your GitHub repository but not to be compiled with your package. Thus, that folder has to be included in a special file called .Rbuildignore.

Luckily, there is a convenience function called usethis::use_data_raw() in the usethis package that does all this. You can run this function and provide your example dataset’s name as an argument, particularly if there is only one dataset, but use_data_raw() can also be run without any argument.

When you run use_data_raw(), it:

  • Creates the data-raw folder.
  • Adds data-raw to .Rbuildignore.
  • Creates a data script where you can paste the script that creates your example data.

In the data script, you will want to have use_data(your_dataset_name) as the last line, which converts the dataset into an .rda file and places it into the data/ folder.

Here’s how you can do it:

# Adding the example dataset
usethis::use_data_raw("example_data")


After running this function, the script file (“example_data.R”) will be opened automatically. Paste the code that creates your example dataset into this file. At the end of the script, add the following line to save the dataset:

# Add prepared data to package
usethis::use_data(example_data)


Here’s a visual guide:



Run the whole script to incorporate your data into your package. This will ensure your dataset is properly saved and included in your package.

Remember to save that example_data.R script file before closing it.

9.3 Pushing again to GitHub

At this point, it is wise to commit and push all the changes to GitHub to keep your project up-to-date and ensure you have a backup of your progress. Follow these steps to do so:

  1. Commit your changes:
  • In RStudio, go to the top-right pane and click on the “Git” tab.
  • You will see a list of the files that have been changed. Check the boxes next to all the files you want to commit.
  • Click on the “Commit” button.
  • In the “Commit message” field, write a descriptive message about the changes you made, for example, “Added example functions and dataset”.
  • Click on the “Commit” button at the bottom right of the window.
  1. Push your changes:
  • After committing, click on the “Push” button in the Git tab.
  • This will upload your committed changes to your GitHub repository.


Here is a visual guide:



In the next section, we’ll focus on testing the functions and example data we have incorporated into our package.




Creating R Packages: A Step-by-Step Guide by Ville Langén is licensed under CC BY-SA 4.0