Shiny: RMarkdown If-statement inside Shiny App - r

Question

I have a tough time to figure out how i can use if statement inside the .Rmd file or so. I could not find anything on stackoverflow...
I am going explain on the example of this shiny app:
library(shiny)
library(markdown)
library(knitr)
server <- function(input, output) {
output$downloadReport <- downloadHandler(
filename = function() {
paste('my-report', sep = '.', switch(
input$format, PDF = 'pdf', HTML = 'html', Word = 'docx'
))
},
content = function(file) {
src <- normalizePath('report.Rmd')
owd <- setwd(tempdir())
on.exit(setwd(owd))
file.copy(src, 'report.Rmd', overwrite = TRUE)
out <- rmarkdown::render('report.Rmd',
params = list(text = input$text),
switch(input$format,
PDF = pdf_document(),
HTML = html_document(),
Word = word_document()
))
file.rename(out, file)
}
)
}
ui <- fluidPage(
tags$textarea(id="text", rows=20, cols=155,
placeholder="Some placeholder text"),
tabPanel("Data",
radioButtons('filter', h3(strong("Auswahlkriterien:")),
choices = list("WerkstoffNr" = 1,
"S-Gehalt" = 2),
selected = 1,inline=TRUE),
conditionalPanel(
condition = "input.filter == '1'",
column(6,
h4("WerkstoffNr auswaehlen:"),
selectInput("select", " ",
choices = seq(1,100,10))),
column(6,
h4("Abmessung auswaehlen:"),
selectInput("abmfrom", "Von:",choices=as.list(seq(20,110,10))),
selectInput("abmto", "Bis:",choices=as.list(seq(20,110,10))),
actionButton("button1", "Auswaehlen"))),
conditionalPanel(
condition = "input.filter == '2' ",
column(6,h4("S-Gehalt auswaehlen:"),
selectInput("sgehalt", "Von:",choices=seq(1,100,10)),
selectInput("sgehalt2", "Bis:",choices=seq(1,100,10))),
column(6,h4("Abmessung auswaehlen:"),
selectInput("abmfrom2", "Von:",choices=as.list(seq(20,110,10))),
selectInput("abmto2", "Bis:",choices=as.list(seq(20,110,10)))))
),
flowLayout(radioButtons('format', 'Document format', c('PDF','HTML', 'Word'),
inline = TRUE),
downloadButton('downloadReport'))
)
shinyApp(ui = ui, server = server)
report.Rmd (it is just this at the moment):
---
title: "Parameterized Report for Shiny"
output: html_document
params:
text: 'NULL'
---
# Some title
`r params[["text"]]`
I would like to inside of my RMarkdown Report to have the input from this part of shiny app:
tabPanel("Data",
radioButtons('filter', h3(strong("Auswahlkriterien:")),
choices = list("WerkstoffNr" = 1,
"S-Gehalt" = 2),
selected = 1,inline=TRUE),
conditionalPanel(
condition = "input.filter == '1'",
column(6,
h4("WerkstoffNr auswaehlen:"),
selectInput("select", " ",
choices = seq(1,100,10))),
column(6,
h4("Abmessung auswaehlen:"),
selectInput("abmfrom", "Von:",choices=as.list(seq(20,110,10))),
selectInput("abmto", "Bis:",choices=as.list(seq(20,110,10))),
actionButton("button1", "Auswaehlen"))),
conditionalPanel(
condition = "input.filter == '2' ",
column(6,h4("S-Gehalt auswaehlen:"),
selectInput("sgehalt", "Von:",choices=seq(1,100,10)),
selectInput("sgehalt2", "Bis:",choices=seq(1,100,10))),
column(6,h4("Abmessung auswaehlen:"),
selectInput("abmfrom2", "Von:",choices=as.list(seq(20,110,10))),
selectInput("abmto2", "Bis:",choices=as.list(seq(20,110,10)))))
)
As we can see there is an If statement inside (concerning filtering option). So it depends on the user which option would like to use to filter the data. I would like to have this option inside of my Report. Just smthg easily like:
if input.filter == 1
Werkstoffnummer: input$select
Abmessung: von input$abmfrom bis input$abmto
else
S : von sgehalt bis sgehalt2
Abmessung: von input$abmfrom2 bis input$abmto2
So in the report will be only printed (if input.filter ==1):
Werkstoffnummer: 1
Abmessung: von 20 bis 30
Thanks so much!

Answer 1

May be I not fully understand you but you can use something like
(example print different text insist on input filter)
---
title: "Untitled"
runtime: shiny
output: html_document
---
```{r eruptions, echo=FALSE}
radioButtons('filter', h3(strong("Auswahlkriterien:")),
choices = list("WerkstoffNr" = 1,
"S-Gehalt" = 2),
selected = 1,inline=TRUE)
conditionalPanel(
condition = "input.filter == '1'",
column(6,
h4("WerkstoffNr auswaehlen:")
))
conditionalPanel(
condition = "input.filter == '2' ",
column(6,h4("S-Gehalt auswaehlen:")))
```
Or use server side ( render UI , like here )
but you cant shared it like static html file :
*"Note: If you are familiar with R Markdown, you might expect RStudio to save an HTML version of an interactive document in your working directory. However, this only works with static HTML documents. Each interactive document must be served by a computer that manages the document. As a result, interactive documents cannot be shared as a standalone HTML file."
Update
If you want download static html
example
report.rmd
---
title: "Untitled"
output: html_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
```{r ,echo=FALSE}
if(input$filter==1){
h1(paste("1",input$ii))
}else{
h1(paste("2",input$ii))
}
```
Shiny
library(shiny)
ui=shinyUI(fluidPage(
radioButtons('filter', h3(strong("Auswahlkriterien:")),
choices = list("WerkstoffNr" = 1,
"S-Gehalt" = 2),
selected = 1,inline=TRUE),
numericInput("ii","1",0),
downloadButton('downloadReport')
))
server=shinyServer(function(input, output) {
output$downloadReport <- downloadHandler(
filename = function() {
paste('my-report', sep = '.', 'html' )
},
content = function(file) {
src <- normalizePath('report.Rmd')
# temporarily switch to the temp dir, in case you do not have write
# permission to the current working directory
owd <- setwd(tempdir())
on.exit(setwd(owd))
file.copy(src, 'report.Rmd')
library(rmarkdown)
out <- render('report.Rmd', html_document())
file.rename(out, file)
}
)
})
shinyApp(ui,server )
Report will contain 1 or 2 insist on radio button and ii input

Answer 2

It sounds like what you want is a template to generate the report. R Markdown is a format for pretty-printing reports rather than generating them.
For report generation, there’s ‹brew›. It lets you generate any file (including R Markdown) using a simple template language. In your case, you could do something like:
<% if (input.filter == 1) { %>
… normal R Markdown code here!
<% } %>
Save this as report.rmd.brew or similar; then, in your report generation code, you need to brew the template before rendering it:
brew::brew('report.rmd.brew', 'report.rmd')
It finds the variables from the current environment by default (this can be configured).