Switching between R and Stata in Markdown: A Deep Dive

Introduction

As data analysts, we often find ourselves working with multiple programming languages and tools. Two popular choices are R and Stata, both widely used for statistical analysis and data visualization. While they share some similarities, they have distinct strengths and weaknesses. In this article, we’ll explore the possibility of switching between R and Stata in Markdown documents, using RStudio’s built-in support for both languages.

Background on RStudio’s Markdown Support

RStudio provides an extension called knit_rmd that allows users to create interactive, HTML-based reports from their Markdown files. These reports can include code chunks written in R, which are then executed on the fly using RStudio’s interactive console.

The knit_rmd package is built on top of Pandoc, a powerful document processing system. When you knit your Markdown file, Pandoc converts it into an HTML file that includes the rendered output from any R code chunks.

RStudio also provides a feature called “engine” which allows users to specify different programming languages for their code chunks. This feature is particularly useful when working with multiple languages, as we’ll see in this article.

Enabling Stata Engine Support

To enable Stata engine support in your Markdown document, you need to add the following line of code:

opts_chunk$set(engine="stata", engine.path=statapath, comment="")

Here’s a breakdown of what this code does:

• engine="stata" specifies that we want to use Stata as the language for our code chunks.
• engine.path=statapath sets the path to the Stata executable on your system. This is typically located in the C:/Program Files (x86)/Stata13/StataSE-64.exe directory, although this may vary depending on your installation location.

Switching between R and Stata

Unfortunately, it appears that switching between R and Stata is not currently possible with RStudio’s built-in support. The user who asked the question provided a working example using knit_rmd, but when they attempted to switch back to R for some code chunks, it did not work.

The reason for this limitation is likely due to the fact that knit_rmd relies on Pandoc to render the HTML output from your Markdown file. When switching between languages, Pandoc needs to be able to handle the differences in syntax and output formats used by R and Stata. This can be a complex task, especially when considering the nuances of both languages.

Using Stata for Regression Analysis

One user who responded to this question provided an alternative approach that uses system() to run Stata scripts from within R. Here’s an example:

# Load required libraries
library(rstudiojs)

# Create a Do-file with arguments
do_file <- function(x) {
  # Define script
  cat("input: ", x, "\n")
  
  # Run script using system()
  system(paste("C:/Program Files/Stata13/StataSE-64.exe", do_file_name := "do_file.do", input: = paste0("\\",x,".txt")))
}

# Call Do-file with arguments
do_file(input="my_data.txt")

# Load resulting Stata file into R
library(readr)
load("C:/Program Files/Stata13/StataSE-64.exe do_file.do")

This code creates a Do-file that takes an input argument, runs the script using system(), and then loads the resulting Stata file into R. This approach allows users to leverage Stata’s strengths in regression analysis while still utilizing R for other tasks.

Conclusion

While switching between R and Stata in Markdown documents is not currently possible with RStudio’s built-in support, there are alternative approaches that can help users achieve their goals. By using system() to run Stata scripts from within R or leveraging Pandoc’s capabilities to render HTML output from your Markdown file, you can still create high-quality reports that incorporate both languages.

If you’re interested in digging deeper into adding functionality to RMarkdown/Pandoc or exploring other alternatives for switching between languages, we recommend checking out the following resources:

• [RStudio’s knit_rmd documentation](https://rstudio.github.io/knitr/docs/ engine.html)
• [Pandoc’s user manual](https://pandoc.org/user Manuals.html)
• Stata’s scripting documentation

Last modified on 2023-11-14