R Shiny Reactive plot using user selected variable

Question

I have recently started using R-Shiny and I have a simple problem due to which I am stuck.

So, I am trying to build a reactive line chart where the user defines the 2 variables from the database.

I have been able to get the variable lists for the drop down but I am not able to use the selected value to plot the line chart.

Refer to the code:

library(shiny)

shinyUI(fluidPage(

# Application title
titlePanel("ARIMAX Forecasting Tool"),

sidebarLayout(
sidebarPanel(

...
mainPanel(
  tabsetPanel(type = "tabs", 
              tabPanel("Plot", plotOutput("plot")), 
              tabPanel("Summary")
  )
)
)
))

and the partial server code

shinyServer(function(input, output) {
output$plot <- renderPlot({
inFile <- input$file1

if (is.null(inFile))
  return(NULL)

content1=read.csv(inFile$datapath, header=input$header, sep=input$sep 
)
h=input$x
k=input$ts

plot(content1$k,content1$h,type="l")
})
})

I have skipped the part where I write the render UI to get the user selected variables.x and ts are the variable selected by the user for the line chart.

I get an error in the main panel area:

need finite xlim values

Answer 1

You have to include a reproducible example- your code does not run as is. This runs for me:

shinyApp(ui=
  shinyUI(fluidPage(
    titlePanel("Title"),
    sidebarPanel(sliderInput("number_points",label = "Number of points",min = 10,max = 1000,value = 100)),
    mainPanel(
      plotOutput("plot")
    )
  )
),
server=shinyServer(function(input, output) {
  output$plot <- renderPlot({
    plot(rnorm(input$number_points))
  })
})
)

Also, check the code reading the file and displaying the plot works outside the shiny app. Indeed the error message suggests something is wrong there.