Calling a graph from another sheet in R - r

Question

My Shiny app is getting a little long, as I'm plotting a variety of graphs in a number of panels. Accordingly, to help with some of the organization, I was wondering if it was possible to move the code for the graphs into a separate r-script, and call those graphs from the original r script.
Adding some further complication, the graphs that I'd like to display all require user input from the Shiny app.
Is it possible to use code from another script in R to plot graphs, and, if so, how? Additionally, as there will be multiple graphs, is it possible to specify which graph from the new r-script will go in the designated location, or will I need to create a separate r-script for each graph (which would defeat the purpose of increased organizational oversight)?
I've written some simplified, reproducible code (see below) that I hope will give you an idea of what I'm looking for. Essentially, I'd like any code that produces a graph within renderPlot() to come from a separate r-script.
Many thanks for any help!
library(shiny)
ui <- fluidPage(
mainPanel(
selectInput("input1","Select an option",choices = c("First","Second")),
plotOutput("plot1"),
plotOutput("plot2")
)
)
server <- function(input, output, session) {
output$plot1 = renderPlot({
if(input$input1=="First"){
##This is where I'd like to call the code for the graph from another sheet.
plot(1,main = input$input1)
}
if(input$input1=="Second"){
##Again, this is where I'd like to code for the graph from another sheet.
plot(2,main = input$input1)
}
})
output$plot2 = renderPlot({
if(input$input1=="First"){
##This is where I'd like to call the code for the graph from another sheet.
plot(1*rnorm(1,10,2),main = input$input1)
}
if(input$input1=="Second"){
##Again, this is where I'd like to code for the graph from another sheet.
plot(2*rnorm(1,50,2),main = input$input1)
}
})
}
shinyApp(ui, server)

Answer 1

You can make a function that takes arguments for the plot that you make like the data and plot title and then passes these arguments to your code that creates the plot. For example, say the only thing that changes is x and the plot title, you can define a function that takes those arguments and then uses them in the code to make the plot. Then you save this in a separate script and call the script using source() in your shiny app.
plots.R
plot_data <- function(x, y=NULL, plot.title){
if(is.null(y)) {
y <- seq(from = 1, by = 1, length.out = length(x))
}
plot(x, y, main = plot.title)
}
Load the function into your global environment using source('plots.R'), make sure plots.R is saved in the same location as your shiny app.
library(shiny)
source("plots.R")
ui <- fluidPage(
mainPanel(
selectInput("input1","Select an option",choices = c("First","Second")),
plotOutput("plot1"),
plotOutput("plot2")
)
)
server <- function(input, output, session) {
output$plot1 = renderPlot({
if(input$input1=="First"){
##This is where I'd like to call the code for the graph from another sheet.
plot_data(1, plot.title = input$input1)
}
if(input$input1=="Second"){
##Again, this is where I'd like to code for the graph from another sheet.
plot_data(2, plot.title = input$input1)
}
})
output$plot2 = renderPlot({
if(input$input1=="First"){
##This is where I'd like to call the code for the graph from another sheet.
plot_data(1*rnorm(1,10,2),plot.title = input$input1)
}
if(input$input1=="Second"){
##Again, this is where I'd like to code for the graph from another sheet.
plot_data(2*rnorm(1,50,2),plot.title = input$input1)
}
})
}
shinyApp(ui, server)
Of course this doesn't look like much of a difference, but with complex plots that span multiple lines, turning your plot code into a function will turn multiple lines into just one.