观察事件中的闪亮反应数据集

Question

I have a very simple app which fails. The reason it fails is that the reactive dataset is available solely within the observeEvent function but not outside. I use observeEvent to get datasets from two different sources wrangled. For this example I simply used cbind. My actual code is much more complicated.

This is a logical / syntax related problem but all my searching came up short. In essence I want merged_data() to be available for all parts of the app.

Minimum repr example - this fails because merged_data() is not available outside of the ObserveEvent.

library(shiny)
library(shinyjs)
library(DT)

# Define UI for application that draws a histogram
ui <- fluidPage(

   # Application title
   titlePanel("testing 1 2 3"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
      ),


      # Show a plot of the generated distribution
      mainPanel(
         fluidRow(
            column(width = 2,
                   offset = 0,
                   align = "center",
                   actionButton(inputId = "fetch_data_inputId",
                                label = "data")

            ) #column
            ,
            column(width = 10,
                   offset = 0,
                   align = "center",
                   DT::dataTableOutput("DT1")
            ) #column

         )#fluidrow
      )
   )
)

# Define server logic required to draw a histogram
server <- function(input, output,session) {

   observeEvent(input$fetch_data_inputId, {

      req(iris) 

      button_data <- colnames(iris)

      merged_data <- reactive({

         if( !is.null(cbind(iris[,1:4],iris3))) {
            cbind(iris[,1:4],iris3)
         } else {NULL}
      })


   }) #observeevent

   output$DT1 <- renderDataTable({#

      rendered_table <- merged_data()

      DT::datatable(rendered_table)
   })   


}

# Run the application 
shinyApp(ui = ui, server = server)

Minimum repr example - this works because the datatable is created within the ObserveEvent.

library(shiny)
library(shinyjs)
library(DT)

# Define UI for application that draws a histogram
ui <- fluidPage(

   # Application title
   titlePanel("testing 1 2 3"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
      ),


      # Show a plot of the generated distribution
      mainPanel(
         fluidRow(
            column(width = 2,
                   offset = 0,
                   align = "center",
                   actionButton(inputId = "fetch_data_inputId",
                                label = "data")

            ) #column
            ,
            column(width = 10,
                   offset = 0,
                   align = "center",
                   DT::dataTableOutput("DT1")
            ) #column

         )#fluidrow
      )
   )
)

# Define server logic required to draw a histogram
server <- function(input, output,session) {

   observeEvent(input$fetch_data_inputId, {

      req(iris) 

      button_data <- colnames(iris)

      merged_data <- reactive({

         if( !is.null(cbind(iris[,1:4],iris3))) {
            cbind(iris[,1:4],iris3)
         } else {NULL}
      })


      output$DT1 <- renderDataTable({#

         rendered_table <- merged_data()

         DT::datatable(rendered_table)
      })   

   }) #observeevent



}

# Run the application 
shinyApp(ui = ui, server = server)

What I really need is for the reactive dataset to continue being created within observeEvent but to be accessible outside of the ObserveEvent environment so that i use it in other parts of the app, but I suspect it's the wrong approach. So anything that works would be great.

Answer 1

library(shiny)
library(shinyjs)
library(DT)

# Define UI for application that draws a histogram
ui <- fluidPage(

   # Application title
   titlePanel("testing 1 2 3"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
      ),


      # Show a plot of the generated distribution
      mainPanel(
         fluidRow(
            column(width = 2,
                   offset = 0,
                   align = "center",
                   actionButton(inputId = "fetch_data_inputId",
                                label = "data")

            ) #column
            ,
            column(width = 10,
                   offset = 0,
                   align = "center",
                   DT::dataTableOutput("DT1")
            ) #column

         )#fluidrow
      )
   )
)

# Define server logic required to draw a histogram
server <- function(input, output,session) {

   merged_data <- eventReactive(input$fetch_data_inputId, {
      req(iris) 

      button_data <- colnames(iris)

      if( !is.null(cbind(iris[,1:4],iris3))) {
         cbind(iris[,1:4],iris3)
      } else {NULL}

   }) #eventReactive

   output$DT1 <- renderDataTable({#
      rendered_table <- merged_data()
      DT::datatable(rendered_table)
   })   
}

# Run the application 
shinyApp(ui = ui, server = server)