Why R Packages Two Different Directories

R Programming

Hey there, fellow data enthusiasts! Today, I want to delve into a fascinating aspect of R packages that has intrigued me for quite some time: the existence of two different directories within R packages. As someone who has spent countless hours developing and utilizing R packages, I’ve often pondered the reasons behind this dual-directory structure. So, let’s embark on this investigation together and uncover the intricacies behind this design choice.

The Two Different Directories in R Packages

When you create an R package, you’ll notice that it contains two distinct directories: man and R. These directories play essential roles in organizing and storing the functionalities of the package. The man directory houses the documentation files for the functions and datasets provided by the package. On the other hand, the R directory is where the actual R code, including function definitions and dataset creations, resides.

Now, you might be wondering, “Why separate the code and documentation into two different directories?” Well, the separation serves a crucial purpose. By keeping the documentation separate from the code, it allows for easier maintenance and management of the package. This division also aligns with the best practices for package development, promoting clarity and organization.

The man Directory: Documentation at Its Core

The man directory is where the documentation source files are located. These files, typically written in Rd format, provide detailed information about the functions, datasets, and usage examples within the package. When users access the help pages for a specific function or dataset using the ?function_name command, they are essentially accessing the content from the man directory.

From a developer’s perspective, maintaining comprehensive and well-organized documentation is pivotal for ensuring that the package users can easily understand and utilize the functionalities. The separation of the man directory enables developers to focus solely on documentation management without interference from the codebase.

The R Directory: Home to the Code

On the other side, the R directory contains the R script files that define the functions, classes, and datasets offered by the package. This is where the magic happens – the implementation of the package’s features through R code. By housing the code separately from the documentation, the R directory ensures that developers can focus on the functionality and logic of the package without being encumbered by the documentation-related files.

Furthermore, this division encourages code modularity and encapsulation, serving as a guiding principle for writing clean and maintainable R packages. It fosters a clear separation between the internal workings of the package and the user-facing documentation, reinforcing the package’s coherence and usability.


In conclusion, the presence of two different directories within R packages – man and R – is a deliberate and well-thought-out design choice. It reflects the emphasis on organization, maintainability, and best practices in package development. Embracing this dual-directory structure not only enhances the clarity and accessibility of the package but also reinforces the principles of good software design within the realm of R package development.

As I continue to explore the nuances of R package development, I find myself deeply appreciative of the thoughtful considerations that have gone into shaping the structure of R packages. It’s these subtle yet consequential details that truly showcase the craftsmanship and expertise embedded within the R programming ecosystem.