Customize labels on sliderInput

[Phil Brockman]

Hello,

I'm working on a project where I have this line of code in the UI.R sliderInput("ps", "Select point size", min=.5,value=1, max=1.5, step=.1).  Instead of having ".5" on the upper left and "1.5" on the upper right, is there a way that I can change these to "small" and "large" respectively?  It would also be nice if I could label the tick mark in the middle as "middle" as well, but having the text on the extremes is my primary goal.

Thank you!

[Sigbert Klinke]

For slider with a logarithmic scale I used

    ticks <- ticks(length(var), nmin=30)
    sliderInput(inputId   = "size",
                label     = "Sample size (n)",
                min       = 1,
                max       = length(ticks),
                value     = 1,
                ticks     = ticks,
                step      = 1)

The ticks are shown below the slider. Above it will still show 1...length(ticks) and also input$size will have the values 1...length(ticks). To get the correct sample size I have to access ticks[input$size]. Best Sigbert

[Sigbert Klinke]

UPDATE: This does not work anymore with Shiny 0.11.x and creates the warnings

Warnung in if (ticks) { :
  Bedingung hat L?nge > 1 und nur das erste Element wird benutzt
Warnung in if (!is.na(attribValue)) { :
  Bedingung hat L?nge > 1 und nur das erste Element wird benutzt

However, since Ion.RangeSlider provides a values element for custom labels you can manipulate the input element from R directly and it return it to shiny:

 ticks  <- c(90, 95, 99, 99.9)
 values <- paste0(' data-values="', paste0(ticks, collapse=','), '"/>')
 html   <- sliderInput("foo", min=1, max=length(ticks), ticks=T)
 html   <- sub('/>', values, html, fixed=T)
 html

Note: Setting ticks to TRUE or FALSE does not change the behaviour of the slider. It changes only if all the values are shown under the slider or not. The only limitation seems that elements in ticks should not contain commas since Ion.RangeSlider uses split(",") to decompose the data-values element.

[mbh]

Hello Sigbert,

I tried your code but I wasn't able to get it work correctly. The surprising thing is that it's working when I remove the "#" in the commented line.

ui <- pageWithSidebar(

  headerPanel("Slider labels"),

  sidebarPanel(

#     sliderInput("foo2", label = "slider 1 :", min = 1, max = 4, value = 1),

    uiOutput("slider")

  ),

  mainPanel()

)

server <- function(input, output) {

  output$slider <- renderUI ({

    ticks  <- c(90, 95, 99, 99.9)

    values <- paste0(' data-values="', paste0(ticks, collapse=','), '"/>')

    html   <- sliderInput("foo", label = "slider 2:", min=1, max=length(ticks), ticks=T, value = 1)

    html   <- sub('/>', values, html, fixed=T) 

    html

  })

}

runApp(list(ui = ui, server = server))

Thanks for your help,

Matt

[Winston Chang]

Sigbert - Could you file an issue about custom ticks labels in the Shiny issue tracker?

Also, your code doesn't work for me (and I also wouldn't expect it to work, since it's trying to modify the text of an object that isn't actually text).

-Winston

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[Sigbert Klinke]

Hi,

yep, in another example my code did not work too. I did yesterday evening a modified version, but I still have to try on my first example and to make it a bit more secure.

  output$sizeUI <- renderUI({
    args       <- mmstat$UI$size  # fixed parameters for sliderInput stored in a list
    args$min   <- 1
    args$max   <- length(args$ticks)
    if (sessionInfo()$otherPkgs$shiny$Version=="0.11") {
      ticks <- paste0(args$ticks, collapse=',')
      args$ticks <- T
      html  <- do.call('sliderInput', args)
      html$children[[2]]$attribs[['data-values']] <- ticks;
    } else {
      html  <- do.call('sliderInput', args)    
    }
    html
  })

[Sigbert Klinke]

Hi,

that is what I'am going to use for shiny 0.10.4 and 0.11:

mmstat.sliderInput <- function (...) {
  iapply <- function (l) {
    ret <- l
    if (is.list(l)) {
      if (!is.null(ret$name) && (ret$name=='input')) {
        ret$attribs[['data-values']] <- ticks
      } else {
        for (i in seq(ret)) ret[[i]] <- iapply(ret[[i]])
      }
    }
    ret
  }
 
  args <- list(...)
  if ((compareVersion(mmstat$shiny, "0.11")>=0) && !is.null(args$ticks) && length(args$ticks)) {

    ticks      <- paste0(args$ticks, collapse=',')
    args$ticks <- T
    html       <- do.call('sliderInput', args)

    html       <- iapply(html)  
  } else {

    html      <- do.call('sliderInput', args)
  }
  html
}

Basically iapply looks (recursively) for a list element with ...$name=='input' and then adds a  ...$attribs[['data-values']] element.And I call it by

  output$sizeUI <- renderUI({
    mmstat.log('sizeUI')
    args       <- mmstat$UI$size
    args$min   <- 1
    args$max   <- length(args$ticks)
    do.call('mmstat.sliderInput', args)
  })

Maybe the code could be simplified/elegant by an R guru.

[mbh]

Thank you Sigbert.

Here is a solution for my example :

ui <- pageWithSidebar(
  headerPanel("Slider labels"),
  sidebarPanel(

    uiOutput("slider")
  ),
  mainPanel()
)

server <- function(input, output) {
  output$slider <- renderUI({

      args       <- list(inputId="foo", label="slider :", ticks=c(90,95,99,99.9), value=c(2,3))

      args$min   <- 1
      args$max   <- length(args$ticks)

      if (sessionInfo()$otherPkgs$shiny$Version>="0.11") {

        ticks <- paste0(args$ticks, collapse=',')
        args$ticks <- T
        html  <- do.call('sliderInput', args)

        html$children[[2]]$attribs[['data-values']] <- ticks;

      } else {
        html  <- do.call('sliderInput', args)    
      }

      html
    })

}

runApp(list(ui = ui, server = server))