R, Shiny Setting DataTable ID - r

Question

I have created a large number of data tables using mapply, however, I need to access the data tables in a following step. R assigns random IDs to these tables if the user does not specify the IDs. Here is an example of what I would like to do:
library(shiny)
ui <- fluidPage(
h2("Last clicked:"),
verbatimTextOutput("last_clicked"),
actionButton("reset", "Reset clicked value"),
h2("Datatable:"),
DT::dataTableOutput("dt")
)
server <- function(input, output) {
# the last clicke value
output$last_clicked <- renderPrint({
str(last())
})
output$dt <- DT::renderDataTable({
DT::datatable(head(mtcars, 2), elementId = "DT_Test")
})
observeEvent(input$dt_cell_clicked, {
validate(need(length(input$dt_cell_clicked) > 0, ''))
print("You clicked something!")
})
myProxy = DT::dataTableProxy('dt')
last = reactiveVal(NULL)
observe({
last(input$dt_cell_clicked)
})
observeEvent(input$reset, {
DT::selectRows(myProxy, NULL)
last(NULL)
output$dt <- DT::renderDataTable({
DT::datatable(head(mtcars, 2))
})
})
}
shinyApp(ui, server)
If I look at the html, the elementID did not change to what I wanted, in fact, R gives the warning:
Warning in origRenderFunc() :
Ignoring explicitly provided widget ID "DT_Test"; Shiny doesn't use them

Answer 1

Even after the call, still not sure what you are trying to do.
But if you have a list of datatables and you want to access them, it works rather well like this:
library(shiny)
library(purrr)
ui <- fluidPage(
h2("Last clicked:"),
verbatimTextOutput("last_clicked"),
h2("elementId values"),
verbatimTextOutput("elementId_values"),
actionButton("reset", "Reset clicked value"),
h2("Datatable:"),
DT::dataTableOutput("dt")
)
server <- function(input, output) {
# the last clicke value
output$last_clicked <- renderPrint({
str(last())
})
table <- DT::datatable(head(mtcars, 2), elementId = "DT_Test")
table2 <- DT::datatable(tail(mtcars, 1), elementId = "DT_Test2")
list_of_data_tables <- list(table, table2)
element_ids <- purrr::map(list_of_data_tables, "elementId")
output$elementId_values <- renderPrint({
element_ids
})
output$dt <- DT::renderDataTable({
list_of_data_tables[[which(element_ids == "DT_Test2")]]
})
observeEvent(input$dt_cell_clicked, {
validate(need(length(input$dt_cell_clicked) > 0, ''))
print("You clicked something!")
})
myProxy = DT::dataTableProxy('dt')
last = reactiveVal(NULL)
observe({
last(input$dt_cell_clicked)
})
observeEvent(input$reset, {
DT::selectRows(myProxy, NULL)
last(NULL)
output$dt <- DT::renderDataTable({
DT::datatable(head(mtcars, 2))
})
})
}
shinyApp(ui, server)