selectInput = NULL for numeric column for Shiny widgets

Question

I am having a small problem with widgets in Shiny. After starting Shiny app I would like to have (as default) selected=NULL for all my widgets. However it is not working for numeric columns at all (factor ones are fine), and after starting i get the first value in this column. Even changing numeric to factor does not help.

My code, as example

selectInput("XX", h3("XX:"), choices = as.list(levels(as.factor(data$XY))),selected=NULL)

Answer 1

You can add "" to choices of selectInput

For example

require(shiny)
aaa=data.frame(c("a",'b','c'))
shinyUI(fluidPage(

      selectInput("s1", "Select 1", choices = as.list(c("",levels(as.factor(aaa[[1]])))))


  )
)