Shiny: Dynamic number of datatables

Question

I'm using the attached code to generate sub-tables based on groups. For some reason only the last portion of the data is rendered for every table. It would be great if someone can tell me what is going wrong.

BR

library(shiny)
library(shinydashboard)
library(DT)
library(data.table)

tabnames <- LETTERS[1:6]

DT <- data.table(mtcars[1:30,], keep.rownames=TRUE)
DT[, grp:=rep(tabnames, each=trunc(nrow(mtcars)/length(tabnames)))]


ui = dashboardPage(
  dashboardHeader(title = "Dynamic DTs"),
  dashboardSidebar(),
  dashboardBody(
    uiOutput("tables"),
    p(),
    verbatimTextOutput("selectedCells")
  )
  )


server <- function(input, output, session) {
  output$tables <- renderUI({
    output_list <- list()
    for(i in seq(tabnames)){
      output_list[[i]] <- column(4, DT::dataTableOutput(outputId=tabnames[i]))
    }
    print(fluidRow(output_list))
    return(fluidRow(output_list))
  })


  for(i in seq(tabnames)){
    tabname <- tabnames[i]
    local({
      print(DT[grp %in% tabname, 1:3])
      output[[tabname]] <- DT::renderDataTable({
        DT[grp %in% tabname, 1:3]
      }, selection=list(mode="multiple", target="cell"))
    })
  }
  output$selectedCells <- renderPrint(input$A_cells_selected)
}

shinyApp(ui = ui, server = server)

Answer 1

Ok, found a solution: needed to pass it in a separate variable:

library(shiny)
library(shinydashboard)
library(DT)
library(data.table)

tabnames <- LETTERS[1:6]

DT <- data.table(mtcars[1:30,], keep.rownames=TRUE)
DT[, grp:=rep(tabnames, each=trunc(nrow(mtcars)/length(tabnames)))]


ui = dashboardPage(
  dashboardHeader(title = "Dynamic DTs"),
  dashboardSidebar(),
  dashboardBody(
    uiOutput("tables"),
    p(),
    verbatimTextOutput("selectedCells")
  )
  )


server <- function(input, output, session) {
  output$tables <- renderUI({
    output_list <- list()
    for(i in seq(tabnames)){
      output_list[[i]] <- column(4, DT::dataTableOutput(outputId=tabnames[i]))
    }
    print(fluidRow(output_list))
    return(fluidRow(output_list))
  })


  for(i in seq(tabnames)){
    tabname <- tabnames[i]
    local({
      subDT <- DT[grp %in% tabname, 1:3]
      output[[tabname]] <- DT::renderDataTable({
        subDT
      }, selection=list(mode="multiple", target="cell"))
    })
  }
  output$selectedCells <- renderPrint(input$A_cells_selected)
}

shinyApp(ui = ui, server = server)