CODEWITHSUNDEEP
rshiny
R Subramanyam
R Subramanyam

Reputation: 1

Changing color of renderText based on a condition

server.R

reference <- input$a * input$b (More complex formula)

output$text <- rendertext({
if(reference > 20)
# Some text in red
else
# Some text in green
)}

I tried using conditionalPanel but it does not let me change panels based on a reactive output.

Thanks in advance

Upvotes: 0

Views: 2766

Answers (1)

RmIu
RmIu

Reputation: 4467

You could do something like this

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      # Input to react to
      sliderInput('slider1','Render text format condition',-1000,1000,value=0,step=1)
    ),
    mainPanel(
      # Text input
      textInput('txtIn','Text input'),
      # Text output
      htmlOutput('txtOut')
    )
  )
)

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

  output$txtOut <- renderText({ 
    # Split into words
    words <- strsplit(input$txtIn,' ')[[1]]
    outTxt <- ' '

    # Parse input based on logic
    if(length(words) == 0) return('')

    # Loop trough words
    for (i in 1:length(words)){
      curr.word <- words[i]

      # If string can be converted to a number
      if(!is.na(as.numeric(curr.word))){
        curr.word.num <- as.numeric(curr.word) # Just in case

        # Determine formating
        if (curr.word.num >= input$slider1 ){
          font <- 'green'
        } else if (curr.word.num < input$slider1){
          font <- 'red'
        } else {
          font <- 'gray'
        }

        # Create html
        formatedFont <- sprintf('<font color="%s">%s</font>',font,curr.word) 

        # Append to text to show
        outTxt <- paste(outTxt, formatedFont,collapse=' ')

      } else{
        outTxt <- paste(outTxt, curr.word,collapse=' ')
      }
    }
    outTxt
  })

}

runApp(shinyApp(ui,server))

Here the text input is parsed to color numbers smaller than the slider input red and larger than the slider input green. Normal text is not formatted.

The trick is using some html formatting in the output text

Upvotes: 3

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