Reading in a file in R Shiny

Question

So I am building an app in R shiny that requires the user to upload a .csv file. Once read in by R shiny, I am unsure how to actually manipulate that object to use. The gene

Answer 1

There is a good example here http://shiny.rstudio.com/gallery/file-upload.html. But for completeness, I've included the working answer below. The key point is that you should reference the file using file$datapath, and also to check if input is NULL (when user hasn't uploaded a file yet).

server.R

#server.R
library(shiny)

shinyServer(function(input, output) {

    observe({
        file1 = input$file1
        file2 = input$file2
        if (is.null(file1) || is.null(file2)) {
            return(NULL)
        }
        data1 = read.csv(file1$datapath)
        data2 = read.csv(file2$datapath)
        output$plot <- renderPlot({
            plot(data1[,1],data2[,2])
        })
    })

})

ui.R

library(shiny)

#ui.R
# Define UI for random distribution application 
shinyUI(fluidPage(

    # Application title
    titlePanel("ORR Simulator"),

    # Sidebar with controls to select the random distribution type
    # and number of observations to generate. Note the use of the
    # br() element to introduce extra vertical spacing
    sidebarLayout(
        sidebarPanel(
            fileInput('file1', 'Select the XXX.csv file',
                      accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
            tags$hr(),
            fileInput('file2', 'Select the YYY.csv file',
                      accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
            tags$hr(),
            numericInput("S", "Number of simulations to run:", 100)
        ),
        mainPanel(
            plotOutput("plot")
        )
    ))
)