Generating Certificates of Attendance Using R

· 610 words · 3 minute read
Blog
Data Science · events · R markdown · LaTeX · R language

Saghir Bashir (www.ilustat.com)

Sometimes after an event you need to issue certificates to the participants. How do you normally produce several certificates automatically? There are different ways to do it and here we share our approach after a recent community event1. We used R to automatically generate the certificates using R markdown and LaTeX language.

Objective

The key objective was to produce PDF certificates that could be emailed to attendees (see above for an example).

How did it work?

We started with a certificate template in R markdown format (with LateX) containing the following tags <<ATTENDEE_NAME>>, <<EVENT_NAME>>, <<EVENT_DATE>> and <<EVENT_LOCATION>>. These tags were replaced by attendee and event information from a data.frame. The PDF certificates were produced using rmarkdown::render() whilst looping over the attendee data.frame.

Requirements

  1. A fixed working directory using set_here()2.

  2. Dataset with attendee and event (name, date and location) information.

  3. A certificate template in R markdown format.

Set up

library(tidyverse)
library(rmarkdown)
library(stringr)
library(here)

set_here() # Need this later especially when rendering R markdown

Dataset of Attendees

Let assume that our dataset of attendees is as follow:

attendees <- read_csv(here("AttendeeList.csv")) %>%
  mutate(filePDF = str_c("PDF/", row_number(), "_",
                         str_replace_all(Name, fixed(" "), "_"), ".pdf")) %>%
  select(filePDF, Name, Event, Date, Location)
attendees
## # A tibble: 3 x 5
##   filePDF                 Name          Event            Date              Location      
##   <chr>                   <chr>         <chr>            <chr>             <chr>         
## 1 PDF/1_Nina_Maccari.pdf  Nina Maccari  Tidyverse Basics 6th February 2018 Lisbon, Portu…
## 2 PDF/2_Don_Leonardo.pdf  Don Leonardo  Tidyverse Basics 6th February 2018 Lisbon, Portu…
## 3 PDF/3_Eva_Jane_Rhys.pdf Eva Jane Rhys Advanced ggplot2 9th February 2018 Lisbon, Portu…

Certificate Template

Next we developed a certificate template using R markdown, with tags (i.e. << ... >>) for the attendee and event information. Our template is saved in a file called Certificate_Rmd_Template.txt:

---
title: ''
output: pdf_document
latex_engine: xelatex
classoption: landscape
header-includes:
- \renewcommand{\familydefault}{\sfdefault}
---

\pagenumbering{gobble}

\begin{center}
  {\Huge\bf Certificate of Attendance} \\
  \vfill
  {\Huge\bf <<ATTENDEE_NAME>>} \\
  \vfill
  {\Huge\it <<EVENT_NAME>>}
  \bigskip \\
  {\Large\it  <<EVENT_DATE>>}
  \bigskip \\
  {\Large\it <<EVENT_LOCATION>>} \\
\end{center}

\vfill

\begin{center}
\includegraphics[height=4cm]{images/Rlogo.png}
\includegraphics[height=4cm]{images/NotHexLogo.png}
\end{center}

Certificate Generation

The certificates were generated using a function that combines the previous steps. The comments in the function code below describe what is going on.

certificate <- function(template, attendeeName, event, eDate, eLocation, outPDF, knitDir){
  cat("\n Starting:", outPDF, "\n")

  # Create a temporary Rmd file with the attendee and event information.  
  templateCert <- read_file(template)
  tmpRmd <- templateCert %>%
    str_replace("<<ATTENDEE_NAME>>", attendeeName) %>%
    str_replace("<<EVENT_NAME>>", event) %>%
    str_replace("<<EVENT_DATE>>", eDate) %>%
    str_replace("<<EVENT_LOCATION>>", eLocation)
  
  # The knitdir has to be defined for the rmarkdown::render to work.
  RmdFile <- tempfile(tmpdir = knitDir, fileext = ".Rmd")
  write_file(tmpRmd, RmdFile)

  # Creating the certificates using R markdown.
  rmarkdown::render(RmdFile, output_file = here(outPDF), quiet = TRUE)
  
  # Temporary .Rmd file can be deleted.
  file.remove(RmdFile)
  cat("\n Finished:", outPDF, "\n")
}

Now we can create all the certificates by looping over the attendee data.frame.

for (i in seq_len(nrow(attendees))) {
  with(attendees,
       certificate(template = here("Certificate_Rmd_Tempate.txt"),
                   Name[i], Event[i], Date[i], Location[i], filePDF[i], here())
  )
}
## 
##  Starting: PDF/1_Nina_Maccari.pdf 
## 
##  Finished: PDF/1_Nina_Maccari.pdf 
## 
##  Starting: PDF/2_Don_Leonardo.pdf 
## 
##  Finished: PDF/2_Don_Leonardo.pdf 
## 
##  Starting: PDF/3_Eva_Jane_Rhys.pdf 
## 
##  Finished: PDF/3_Eva_Jane_Rhys.pdf

You can view the PDF certificates:

Summary

We have presented a way to create PDF certificates of attendance based on a user defined “template”. The template was populated with the attendee and event information from which PDF certificates were generated using R markdown. This approach can be used to produce other types of documents, for example, “mail merges” and setting different exercises or exams for students. Our code can be run directly from the R console or as a batch job thanks to the rmarkdown and here packages.

  1. Data Science Unplugged: “Data Science in Practice” Event↩

  2. See Jenny Bryan’s excellent article about using the here package↩

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