CODEWITHSUNDEEP
rshiny
Ignacio
Ignacio

Reputation: 7938

evaluate function in shiny and print values

Suppose I have a function that takes an input an returns a data frame with two values. I want to render the following text: Value 1 is df1$value1, and value 2 is df1$value2. Is there a way of doing this?

This is the code that I have right now:

## app.R ##
library(shinydashboard)

ui <- dashboardPage(
  dashboardHeader(title = "Basic dashboard"),
  dashboardSidebar(),
  dashboardBody(
    # Boxes need to be put in a row (or column)
    fluidRow(
      box(renderText(paste('Value 1 is', "df1$value1"))),

      box(
        title = "Controls",
        sliderInput("slider", "X:", 1, 100, 50)
      )
    )
  )
)

my.func <- function(X){
  df1 = data.frame(value1=X*X, value2=sqrt(X))
  return(df1)
}

server <- function(input, output) {

  output$df1 <- renderTable({
    my.func(input$slider)
  })
}

shinyApp(ui, server)

Thanks!

Upvotes: 0

Views: 978

Answers (1)

zero323
zero323

Reputation: 330093

You can prepare output inside server function like this:

server <- function(input, output) {
    output$df1 <- renderUI({
        df <- my.func(input$slider)
        lapply(
            1:ncol(df),
            function(i) {
                force(i)
                p(paste("Value", i, "is", df[, i]))
            }
        )
    })
}

and then bind in inside ui function using uiOutput('df1').

Alternatively you can use observe block and assign specific values to output in the loop:

observe({
    df <- my.func(input$slider)
    for (i in 1:ncol(df)) {
        output[[paste0('value', i)]] <- renderText({ df[, i] }) 
    }
})

Then you can simply use textOutput in the ui like this textOutput('value1').

Upvotes: 1

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