CODEWITHSUNDEEP
rshiny
hmbotelho
hmbotelho

Reputation: 45

shiny: read text content of verbatimTextOutput

Is it possible to read the text content of a verbatimTextOutput element within a Shiny app as a variable?

The idea of the sample app below is that when the user clicks button1, the content of text2 gets updated and shows whatever is in text1 ("Hello world" in this case).

The observeEvent handler below generates this error : Warning: Error in $.shinyoutput: Reading objects from shinyoutput object not allowed. but this looked to me the closest I managed to get to a solution.

Any help would be appreciated.

Thanks,

Hugo

library(shiny)

shinyApp(
    ui = basicPage(verbatimTextOutput("text1"),
                   actionButton("button1", "Read & copy text!"),
                   verbatimTextOutput("text2")),

    server = function(input, output, session) {

        output$text1 <- renderText("Hello world")
        output$text2 <- renderText("Waiting for new text...")

        observeEvent(input$button1, {
            output$text2 <- output$text1
        })
    }
)

Upvotes: 0

Views: 4671

Answers (3)

Rolando Tamayo
Rolando Tamayo

Reputation: 286

Use shinyjs

If you want to read a text on any tag with an id and save it in an input. You can use the pakage shinyjs and some js code to read the text and then use Shiny.onInputChange () to create the input. The code below solves your problem

library(shiny)
library(shinyjs)

shinyApp(
  ui = basicPage(useShinyjs(),verbatimTextOutput("text1"),
                 actionButton("button1", "Read & copy text!"),
                 verbatimTextOutput("text2")),
  
  server = function(input, output, session) {
    
    output$text1 <- renderText("Hello world")
    output$text2 <- renderText("Waiting for new text...")
    
    observeEvent(input$button1, {
      runjs("var textin1=$('#text1').text();
            Shiny.onInputChange('textin1', textin1);
            ")
      output$text2 <- renderText({input$textin1})
    })
  }
)

Upvotes: 0

Andryas Waurzenczak
Andryas Waurzenczak

Reputation: 469

    library(shiny)

    shinyApp(
      ui = basicPage(textInput("text1","","",placeholder = "Hello World"),
                     actionButton("button1", "Read & copy text!"),
                     verbatimTextOutput("text2")),

      server = function(input, output, session) {

        text2 <- eventReactive(input$button1,{
          input$text1
        })

        output$text2 <- renderText({
          validate(
            need(input$button1,"Waiting for new text....")
          )
          text2()
        }
        )
      }
    )

But if you want exactly the same way as you did. So, here it is.

    library(shiny)

    shinyApp(
      ui = basicPage(verbatimTextOutput("text1"),
                     actionButton("button1", "Read & copy text!"),
                     verbatimTextOutput("text2")),

      server = function(input, output, session) {

        output$text1 <- renderText("Hello world")
        output$text2 <- renderText({
          validate(
            need(input$button1,"Waiting for new text...")
          )
          "Hello world"
          })
      }
    )

Upvotes: 0

Dinesh.hmn
Dinesh.hmn

Reputation: 711

You can store the output of the text1 object to a variable and pass that variable. I would suggest that you use the session$userData object because it makes a part of your shiny session and you dont have to declare the variable globally. Below is the code

library(shiny)

shinyApp(
  ui = basicPage(verbatimTextOutput("text1"),
                 actionButton("button1", "Read & copy text!"),
                 verbatimTextOutput("text2")),

  server = function(input, output, session) {

    output$text1 <- renderText({
      session$userData$text1 <- "Hello world"
      session$userData$text1})
    output$text2 <- renderText("Waiting for new text...")

    observeEvent(input$button1, {
      output$text2 <- renderText(session$userData$text1)
    })
  }
)

Upvotes: 1

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