How to Compare TextInput in Shiny for Equality with Another Object?

Question

I have been writing a Shiny App which involves, in part, the comparison of a user's text input with a vector or string, written into the code. I have not been able to get this to work, however, and I am at a loss as to why, as it throws no errors. It will simply print/paste the condition specified for when the comparison is FALSE, i.e. not equal. When I run all the steps through base R (minus anything to do with Shiny), it does return TRUE, so I am not sure what is getting lost in the translation between input and comparing to an R object. I have tried both isTRUE(all.equal(...)) and identical(...) and isTRUE(identical(...)), and none of it seems to work or is returning a FALSE condition. I've included code below which includes a variation of it - I have been using "ding" as a comparison to the input, just as something short and easy to type in to test it.

Any help would be much appreciated, at my wit's end!

---

library(shiny)
library(stringr)

site <- c(rep("A",5), rep("B",5), rep("C",5), rep("D",5))

my.num <- 1:20

temp <- rnorm(20, 5, 1)

growth <- 5*temp + rnorm(20,0,2)


my.data <- data.frame(site=site, my.num=my.num, temp=temp, growth=growth)

my.data

ui <- pageWithSidebar(
  headerPanel('Data Wrangler')
  ,
  sidebarPanel(
    textInput("combination", "Combine the several variables into one data frame with R code:", NULL),
    actionButton("go5", "GO!")
  )
  ,
  mainPanel(

    tableOutput("display1"),
    textOutput("text.dsp")

  ))

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

  buttonValue <- reactiveValues(go5=FALSE)


  observeEvent( input$go5, {

str.input <- str_extract(input$combination, "data.frame(site=site, my.num=my.num, temp=temp, growth=growth)")
str2.input <- as.character(str_extract(input$combination, "ding")
comparestring <- "ding"

isolate({

  buttonValue$go5 = FALSE


})
output$display1 <- renderTable({


  if (isTRUE(identical(str.input, "data.frame(site=site, my.num=my.num, temp=temp, growth=growth)")) & buttonValue$go5) {
    my.data
  } else if(isTRUE(all.equal(str2.input,comparestring)) & buttonValue$go5){
    my.data
  } else {
    NULL
  }

})

  })


  session$onSessionEnded({
    print("stop")
    stopApp   
  }) 

}



  shinyApp(ui = ui, server = server)

---

Answer 1

Here is what I think you are after:

(try typing in "ding" and press "go")

library(shiny)

site <- c(rep("A", 5), rep("B", 5), rep("C", 5), rep("D", 5))
my.num <- 1:20
temp <- rnorm(20, 5, 1)
growth <- 5*temp + rnorm(20, 0, 2)

my.data <- data.frame(site = site, my.num = my.num, temp = temp, growth = growth)

ui <- pageWithSidebar(
  headerPanel('Data Wrangler'), 
  sidebarPanel(
    textInput("combination", "Combine the several variables into one data frame with R code:", NULL), 
    actionButton("go5", "GO!")
  ), 
  mainPanel(
    tableOutput("display1"), 
    textOutput("text.dsp")
  ))

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

  tableData <- eventReactive(input$go5, {
    if(input$combination == "ding"){
      return(my.data)
    } else if(input$combination == "data.frame(site = site, my.num = my.num, temp = temp, growth = growth)"){
      return(my.data)
    } else {
      return(NULL)
    }
  })

  output$display1 <- renderTable({
    tableData()
  })  

  session$onSessionEnded({
    stopApp
  }) 

}

shinyApp(ui = ui, server = server)