Centar 15 Centar 15 - 1 month ago 19
R Question

Addressing multiple inputs in shiny

I am building a relatively complicated app, where I have dynamic number of inputs titled:
d1, d2 .. dn. At one point I wanted to try addressing multiple inputs at the same time with:

input[[grep(pattern="d+[[:digit:]]",input)]]


which of course caused an error:

Must use single string to index into reactivevalues


So I was wondering whether someone knew an elegant way to do such a thing?

Answer

You can use names on input :

grep(pattern = "d+[[:digit:]]", x = names(input), value = TRUE)

A working example :

library("shiny")
ui <- fluidPage(
  fluidRow(
    column(
      width = 6,
      lapply(
        X = 1:6,
        FUN = function(i) {
          sliderInput(inputId = paste0("d", i), label = i, min = 0, max = 10, value = i)
        }
      )
    ),
    column(
      width = 6,
      verbatimTextOutput(outputId = "test")
    )
  )
)
server <- function(input, output){
  output$test <- renderPrint({
    sapply(grep(pattern = "d+[[:digit:]]", x = names(input), value = TRUE), function(x) input[[x]])
  })
}
shinyApp(ui = ui, server = server)