Isolate selectInput() reactivity in selected row of a data table


#1

I have a simple shiny app:

 #ui.r
        navbarPage(
          "Application",
          tabPanel("General",
                   sidebarLayout(
                     
                     sidebarPanel(
                       uiOutput("book3"),
                       uiOutput("book2")),
                     mainPanel(
                       
                       DT::dataTableOutput("hot3")
                       
                     )
                   )))
    #server.r
    library(shiny)
    library(DT)
    library(tidyverse)
    server <- function(input, output,session) {
      
      output$book2 <- renderUI({
        selectInput("bk2", "Marginal", choices=c("Marg1","Marg2","Marg3"),selectize = FALSE)
      })
      output$book3<-renderUI({
        
        selectInput("bk3", 
                    "Label", 
                    choices=(rt5()[,1]))
      })
      rt5<-reactive({
        DF=data.frame(
          Label=paste("Test",1:3),
          Marg=input$bk2,
          stringsAsFactors = FALSE
        )
      })
      output$hot3 <-DT::renderDataTable(
        rt5()
        
      )
    }

I want to be able to select a Test from the selectInput() "Label" and then only the relative Marg of this row to change accordinlly to the name that is set in the selectInput() "Marginal". For example if I choose Label->Test 2 and Marginal -> Marg 2 only the Marg in the second row of the table should be named like this and the rest should remain the same. In the current condition everything changes.