CODEWITHSUNDEEP
rshiny
Clarinetist
Clarinetist

Reputation: 1187

Conditioning on input variables and creating new variables in Shiny

ui.R:

library(shiny)

shinyUI(fluidPage(
  checkboxGroupInput("Check1",label=h4 ("Coin Type:"), choices = c("Fair","Unfair (p = 60% for heads)"))
))

server.R:

library(shiny)

shinyServer(function(input, output) {
  if (input$Check1 == "Fair"){
    x <- 1
    output$Value <- renderTable(as.data.frame(x))
  } else { 
    x <- 5
    output$Value <- renderTable(as.data.frame(x))
  }
})

This should be very simple: there should be two check boxes. When "Fair" is checked, give x the value 1; otherwise, 5. Then display it on a data frame.

The problem, I think, is from assigning the variable x. Here is the error I get:

Warning: Error in .getReactiveEnvironment()$currentContext: Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)
Stack trace (innermost first):
    44: .getReactiveEnvironment()$currentContext
    43: .subset2(x, "impl")$get
    42: $.reactivevalues
    41: $ [-- this has a folder directory --]
    40: server [-- this has a folder directory --]
     1: runApp
Error in .getReactiveEnvironment()$currentContext() : 
  Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)

[note that I omitted 41 and 40 above].

How do I deal with this problem? Searching has led me to nothing, and it isn't clear to me how to use reactiveValues.

Upvotes: 0

Views: 718

Answers (1)

Carl
Carl

Reputation: 5779

You need to make x reactive to do what you want like so:

x <- reactive({
  if (input$Check1 == "Fair"){
  1
} else { 
  5  
}
# pass reactive x() to renderTable
output$Value <- renderTable(as.data.frame(x()))

Upvotes: 1

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