DT:: Datatable is displayed twice in a shiny application - r

Question

I have a shiny application in which a dataTable is displayed when the user selects Sector A from the radioButtons menu in the sidebar. The problem is that it is displayed twice. I checked it in browser mode too. Why does this happen I display the whole app here since it may be caused by the if logic of the app. renderTable() works fine so I guess there is an issue with DT
#ui.r
library(shiny)
library(shinythemes)
library(DT)
ui <- fluidPage(
theme=shinytheme("slate") ,
# App title ----
titlePanel("Tabsets"),
# Sidebar layout with input and output definitions ----
sidebarLayout(
# Sidebar panel for inputs ----
sidebarPanel(
uiOutput("rad")
),
# Main panel for displaying outputs ----
mainPanel(
uiOutput("tabers"),
DT::dataTableOutput("table")
)
)
)
#server.r
library(shiny)
library(DT)
server = function(input, output) {
output$rad<-renderUI({
radioButtons("radio", label = "",
choices = list("Home"=1,"About" = 2, "Sector A" = 3, "Sector B" = 4,"Sector C" = 5),
selected = 1)
#selected = character(0))
})
output$tabers<-renderUI({
if(is.null(input$radio)) {
tabsetPanel(
id="tabF",
type = "tabs",
tabPanel("Global"),
tabPanel("Performance")
)
}
else if(input$radio==3){
tabsetPanel(
id="tabC",
type = "tabs",
tabPanel("Constituents",
output$table <- renderDataTable({
mtcars
})
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}
else if(input$radio==4){
tabsetPanel(
id="tabD",
type = "tabs",
tabPanel("Constituents"
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}
else if(input$radio==5){
tabsetPanel(
id="tabE",
type = "tabs",
tabPanel("Constituents"
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}
else if(input$radio==2){
}
# Left last else in here but should not get called as is
else if(input$radio==1){
tabsetPanel(
id="tabA",
type = "tabs",
tabPanel("Global"),
tabPanel("Performance" )
)
}
})
}

Answer 1

It looks like renderTable does the same thing. For some reason, the output of renderDataTable({mtcars}) gets displayed twice, first through uiOutput, second through dataTableOutput() (both are in mainPanel). Commenting the line dataTableOutput("table") fixes the behavior in that it shows the table only once. Interestingly, removing the assignment like so:
else if(input$radio==3){
tabsetPanel(
id="tabC",
type = "tabs",
tabPanel("Constituents",
renderDataTable({
mtcars
})
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}
also renders the table once. So it looks like when inside renderUI, renderDataTable just creates the output without requiring a dataTableOutput in the UI.
This seems to allow (for better or worse) to easily render different tables in different tabs without corresponding output entries in the UI.
else if(input$radio==3){
tabsetPanel(
id="tabC",
type = "tabs",
tabPanel("Constituents",
renderDataTable({
mtcars
})
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}
else if(input$radio==4){
tabsetPanel(
id="tabD",
type = "tabs",
tabPanel("Constituents",
renderDataTable({
iris
})
),
tabPanel("Clusters" ),
tabPanel("Index")
)
}