Shiny - DT - Single row selection, across several DT::tables - r

Question

In the example below, I have 3 DT::datatables. I want the user to be able to select no more than one row from all these tables. I thence use dataTableProxy and selectRow, as per the section "Manipulate An Existing DataTables Instance" in the documentation. It works fine.
However, in my application, I have 24 (call that value N) tables. If I try to adapt the code below to my 24 tables page, I get an horrendous number of lines of code.
What is a smarter way of doing this?
In particular, how can I:
declare the observers dynamically? (answered by user5029763)
know which table (not row) has been clicked upon last? (ie. how to re write reactiveText()?)
EDIT : I copied in user5029763's answer (see below) in the code below.
DTWrapper <- function(data, pl = 5, preselec = c()){
datatable(data,
options = list(pageLength = pl, dom='t',ordering=F),
selection = list(mode = 'single', selected= preselec),
rownames = FALSE)
}
resetRows <- function(proxies, self){
for (i in 1:length(proxies)){
if (self != i){
proxies[[i]] %>% selectRows(NULL)
}
}
}
lapply(1:3, function(id) {
observe({
rownum <- input[[paste0("tab",id,"_rows_selected")]]
if (length(rownum) > 0) { resetRows(proxyList(), id) }
})
})
server = function(input, output) {
output$tab1 <- DT::renderDataTable(DTWrapper(head(mtcars[,1:3]), input$selectTop))
output$tab2 <- DT::renderDataTable(DTWrapper(head(mtcars[,1:3]), input$selectTop))
output$tab3 <- DT::renderDataTable(DTWrapper(head(mtcars[,1:3]), input$selectTop))
proxyList <- reactive({
proxies = list()
for (i in 1:3){
tableID <- paste("tab", i, sep="")
proxies[[i]] = dataTableProxy(tableID)
}
return(proxies)
})
reactiveText <- reactive({
rownum1 <- input$tab1_rows_selected
rownum2 <- input$tab2_rows_selected
rownum3 <- input$tab3_rows_selected
if (length(rownum1) > 0){return(c(rownum1, 1))}
if (length(rownum2) > 0){return(c(rownum2, 2))}
if (length(rownum3) > 0){return(c(rownum3, 3))}
})
output$txt1 <- renderText({
paste("You selected row ", reactiveText()[1]
, " from table ", reactiveText()[2], ".", sep="")
})
}
shinyApp(
ui = fluidPage(
fluidRow(column(4,DT::dataTableOutput("tab1"))
, column(4,DT::dataTableOutput("tab2"))
, column(4, DT::dataTableOutput("tab3")))
,fluidRow(column(4,textOutput("txt1")))
),
server = server
)
The textOutput is: "You selected the Xth row from the Yth table".

Answer 1

After edit:
You could try modules. Another way would be a lapply.
lapply(1:3, function(id) {
observe({
rownum <- input[[paste0("tab",id,"_rows_selected")]]
if (length(rownum) > 0) {
resetRows(proxyList(), id)
msg <- paste0("You selected row ", rownum, ", from table ", id, ".")
output$txt1 <- renderText(msg)
}
})
})