How to set column names as mathematical formulas in data.frame in Shiny?

Question

I am new to Shiny, and I ran into the following problems:

I want to output the column names in a mathematical form, which means, in the table below, y1---> y₁......and y_--->ȳ. I don't know if this is feasible, I have used many methods, but I haven't found a better one yet.

Part of my code is as follows:

  yValues <- reactive({
     data.frame(
       Group=c("1"),
       y1=as.character(c(input$meansy1)),
       y2=as.character(c(input$meansy2)),
       y3=as.character(c(input$meansy3)),
       y4=as.character(c(input$meansy4)),
       y5=as.character(c(input$meansy5)),
       y6=as.character(c(input$meansy6)),
       y_=as.character(c(y_mean())),
       y.Variance=as.character(c(y_Variance())),
       stringsAsFactors=FALSE)
  })

This is the table now:

Answer 1

Here is a way with KaTeX. Put your math code between two pairs of %%.

library(shiny)

js <- " 
$(document).on('shiny:value', function(event) {
  if(event.name === 'table'){
    var matches = event.value.match(/(%%+[^%]+%%)/g);
    var newvalue = event.value;
    for(var i=0; i<matches.length; i++){
      var kcode;
      var x = matches[i].slice(2,-2);
      try{
        var code = '\\\\' + x;
        kcode = katex.renderToString(code)
      } catch(error){
        kcode = katex.renderToString(x)
      }
      newvalue = newvalue.replace(matches[i], kcode);
    }
    event.value = newvalue;
  }
})
" 

ui <- fluidPage(
  tags$head(
    tags$link(rel="stylesheet", href="https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.css", integrity="sha384-9tPv11A+glH/on/wEu99NVwDPwkMQESOocs/ZGXPoIiLE8MU/qkqUcZ3zzL+6DuH", crossorigin="anonymous"),
    tags$script(src="https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.js", integrity="sha384-U8Vrjwb8fuHMt6ewaCy8uqeUXv4oitYACKdB0VziCerzt011iQ/0TqlSlv8MReCm", crossorigin="anonymous"),
    tags$script(HTML(js))
  ),
  titlePanel("Hello Shiny!"),
  mainPanel(
    tableOutput("table")
  )
)

server <- function(input, output) {
  
  yValues <- reactive({
    data.frame(
      Group      = "1",
      "%%y_1%%"  = LETTERS[1:3],
      "%%bar{y}%%" = letters[1:3],
      stringsAsFactors = FALSE,
      check.names = FALSE)
  })
  
  output[["table"]] <- renderTable({
    yValues()
  }, rownames = TRUE)
  
}

shinyApp(ui, server)