[SOLVED] Restrict input type in shiny field

Restrict input type in shiny field

As it is, numericInput accepts both string and numeric inputs. If a string is entered it is converted to NA (try with the code below). Is there a way of not allowing the user to type a string in a numeric field in shiny?

ui <- fluidPage(
  numericInput("num", label = "text not allowed", value = 1),
  verbatimTextOutput("value")
)

server <- function(input, output) {
  output$value <- renderPrint({ input$num })      
}

shinyApp(ui = ui, server = server)

So far, I have added a text output next to the numeric input that warns the user that only numbers are accepted if she enters a string in a numericInput field. This solution is far from ideal for me.

I want it to be impossible for the user to enter a character value in a numeric field.

Solution

You can add validate to your expression, so only number inputs will be allowed. I'm using windows 7 64-bit with Google Chrome (IE will work too)

Note: Shiny version 0.13.2, doesn't work on Firefox.

library(shiny)
ui <- fluidPage(
  numericInput("num", label = "text not allowed", value = 1),
  verbatimTextOutput("value")
)
server <- function(input, output) {

  numbers <- reactive({
    validate(
      need(is.numeric(input$num), "Please input a number")
    )
  })
  output$value <- renderPrint({ numbers() })      
}
shinyApp(ui = ui, server = server)