闪亮的sliderinput功率为2

Question

是否可以创建仅接受2的幂的R Shiny sliderInput？我看到自定义格式here，但不清楚如何添加上标或限制滑块。

Answer 1

是的，来自@neilfws的链接答案是正确的。我已根据您的需求对其进行了调整（必须在浏览器中查看以允许JS运行）：

library("shiny")

# expSlider javascript function
JS.expify <-
  "
// function to exponentiate a sliderInput
function expSlider (sliderId, sci = false) {
  $('#'+sliderId).data('ionRangeSlider').update({
  'prettify': function (num) { return ('2<sup>'+num+'</sup>'); }
  })
}"

# call expSlider for each relevant sliderInput
JS.onload <-
"
// execute upon document loading
$(document).ready(function() {
// wait a few ms to allow other scripts to execute
setTimeout(function() {
// include call for each slider
expSlider('exp_slider', sci = true)
}, 5)})
"

ui <- fluidPage(
  tags$head(tags$script(HTML(JS.expify))),
  tags$head(tags$script(HTML(JS.onload))),

  sliderInput("exp_slider", "Powers of 2 Slider:",
              min = -5, max = 10, value = 1, step = 1),

  br(),

  textOutput("selection")
)

server <- function(input, output, session) {

  output$selection <- reactive({
    paste0("Selected power: ", input$exp_slider, "     Value = ", 2^input$exp_slider)
  })
}

shinyApp(ui, server)