How can I generate pdfs in a loop with R-markdown? - r-markdown

Question

Suppose I have a data.frame like this:
Debts <- data.frame(name= c("Julia Fischer", "Arold Hass", "Michael Pfeifer", "Harry Frank"),
value= c(145, 136, 0, 100))
I want to generate PDFs in a loop, instead of printing like this:
for(i in 1:length(Debts$name)) {
L <- Debts[i,]
if(L[2] > 0){
print(str_c("Hi ", L[1], " you owe me ", L[2], " dollars."))
} else {
print(str_c("Hi ", L[1], " we are even."))
}
}
Is it possible to do it using R-markdown? How can I do that ? I guess that if it is possible, I can generate the pdfs in a nice template too. If it's not possible with R-markdown, is there any other option ?

Answer 1

I was able to do it using Parameterized R Markdown reports. It has some limitations, but it can work. Basically, to the YAML header of the .Rmd you add your params using:
params:
The params you want to use are indented as follows. You can also insert default values to the param (using '3' just to show how):
---
title: "Our accounting"
output: pdf_document
params:
n: 3
---
In our case, I'm using just one parameter "n", Because I'm going to use it as index to my loop.
So, in the console, you can create your loop. Inside it, you can use the function rmarkdown::render() to call the .Rmd script and run the PDFs. You will also need to set the name of the pdfs to be created with "output_file=". Something like this:
for(i in 1:length(Debts$name)) {
name <- Debts$name[i]
rmarkdown::render("debts.Rmd",
params = list(N = i),
output_file = paste0(name, "-debts.pdf")
)
}
In your .Rmd file you'll have something like:
Hi `r Debts$name[params$N]`, you owe me `r Debts$value[params$N]` dollars.