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Andrew B. Collier
Andrew B. Collier

Posted on • Originally published at datawookie.dev on

{emayili} Rendering R Markdown

{emayili} Rendering Plain Markdown

In a previous post I documented a new feature in {emayili}, the ability to render Plain Markdown directly into the body of an email message.

Today I’m announcing the release of a new minor version, 0.5.0, in which {emayili} is now able to render R Markdown into an email. This is a major leap forward for the package.

I should mention that this capability (rendering R Markdown into an email) is already available in the {mailmerge} package, but that only works with Gmail.

Install & Load

You can install this version directly from GitHub as follows.

remotes::install_github("datawookie/emayili", ref = "v0.5.0")
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This version was also published on CRAN on 17 September 2021.

Now load the package.

library(emayili)

# A couple of options to display message body.
#
options(
  envelope_details = TRUE,
  envelope_invisible = FALSE
)
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Check on the installed version.

packageVersion("emayili")

[1] '0.5.0'
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A Simple R Markdown File

For the purposes of illustration let’s use a super simple R Markdown file, pi.Rmd.

--------
title: "Approximating Pi"
output: html_document
--------

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{r}
22 / 7

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Create an empty message object.

msg <- envelope()
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And then render pi.Rmd into the body of the message. In this case I’m going to set the include_css option to FALSE so that the copious volume of CSS is suppressed in the resulting HTML.

msg %>% render("pi.Rmd", include_css = FALSE)

Date: Fri, 17 Sep 2021 10:16:09 GMT
X-Mailer: {emayili}-0.5.0
MIME-Version: 1.0
Content-Type: multipart/related; boundary="b9173ea5"

--b9173ea5
Content-Type: text/html; charset=utf-8
Content-Disposition: inline

<html><body>
<div class="container-fluid main-container">
<div id="header">
<h1 class="title toc-ignore">Approximating Pi</h1>
</div>
<pre class="r"><code>22 / 7</code></pre>
<pre><code>[1] 3.142857</code></pre>
</div>
</body></html>

--b9173ea5--
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The document is inserted as a separate MIME chunk with type text/html.

Let’s move onto a more interesting example.

R Markdown File from Template

Create an R Markdown file using the "github_document" template.

rmd <- "gh-doc.Rmd"

rmarkdown::draft(
  rmd,
  template = "github_document",
  package = "rmarkdown",
  edit = FALSE
)

--------
title: "Untitled"
output: github_document
--------

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{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)


## GitHub Documents

This is an R Markdown format used for publishing markdown documents to GitHub. 
When you click the **Knit** button all R code chunks are run and a markdown 
file (.md) suitable for publishing to GitHub is generated.

## Including Code

You can include R code in the document as follows:

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{r cars}
summary(cars)


## Including Plots

You can also embed plots, for example:

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{r pressure, echo=FALSE}
plot(pressure)


Note that the `echo = FALSE` parameter was added to the code chunk to prevent 
printing of the R code that generated the plot.
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Now we’ll add some addresses to the message object and render the R Markdown.

msg %>%
  to("bob@google.com") %>%
  from("alice@google.com") %>%
  subject("Rendering an R Markdown Document") %>%
  render(rmd)
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Dispatching the email results in the message below.

The message doesn’t need to look this generic. You can make your R Markdown documents as fancy as you want and {emayili} will be happy to send them.

Conclusion

If you haven’t tried {emayili} before, now is a great time to give it a shot. And if you use R for automated reporting, then being able to render R Markdown directly into an email should simplify your workflow.

I gave a talk about these new features (and most of the old features!) at the Birmingham R User Group. The slides are available here.

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