How to update data table with newly calculated calculated values?

update DataTable with newly calculated values

library(shiny)
library(DT)
library(dplyr)
library(purrr)


shinyApp(
  ui = fluidPage(
    tagList(
      fluidRow(
        column(4, h2("input sample size"), 
               tags$p("How can I update the mean and sd after changing sample size?"),
               DT::DTOutput('x1')),
        column(4, h2("Interactive plotting"), 
               tags$p("This needs to be updated after changing sample size"),
               plotOutput("histo")),
        column(4, h2("Updated sample size from input"), DT::DTOutput("updatesize"))
      )
    )
  ),
  
  server = function(input, output) {
    shinyInput = function(FUN, len, id, ...) {
      inputs = character(len)
      for (i in seq_len(len)) {
        inputs[i] = as.character(FUN(paste0(id, i), label = NULL, ...))
      }
      inputs
    }
    
    # obtain the values of inputs
    shinyValue = function(id, len) {
      unlist(lapply(seq_len(len), function(i) {
        value = input[[paste0(id, i)]]
        if (is.null(value)) NA else value
      }))
    }
    
    dt <- reactiveValues(n = 50)
    
    observe({
      set.seed(123)
      # subset from each column in the data set. default values is 50
      dt$subset <- map2(iris[,1:4], dt$n, sample)
      
      # calcualte the mean and sd from subset
      dt$table <- dt$subset %>%
        map_df(~invoke_map(list(sd=sd, mean=mean), ,.), .id="trait") %>%
        mutate(samplesize = shinyInput(
          numericInput, nrow(.), "samplesize_",
          value = 50, width = "75px"
        ))
    })
    
    # rendertable  
    output$x1 <- DT::renderDT(
      {dt$table},
      server = FALSE,
      selection = "single",
      escape = FALSE,
      extensions = "Scroller",
      options = list(
        preDrawCallback = JS("function() {\nShiny.unbindAll(this.api().table().node()); }"),
        drawCallback = JS("function() {\nShiny.bindAll(this.api().table().node()); } "),
        stateSave = TRUE,
        scrollX = TRUE,
        scrollY = 350,
        scroller = TRUE
        
      ))
    
    # plot selected row
    output$histo <- renderPlot({
      req(input$x1_rows_selected)
      
      current.trait <- dt$table$trait[input$x1_rows_selected] %>% 
        as.character()
      
      hist(dt$subset[[current.trait]], main = current.trait)
    })
    
    
    # output from changing sample size
    editedsize <- reactive({
      set.seed(123)
      samplesize <- shinyValue("samplesize_", nrow(dt$table)) 
      subset <- map2(iris[,1:4], samplesize, sample)
      # calcualte the mean and sd from subset
      subset %>%
        map_df(~invoke_map(list(sd=sd, mean=mean), ,.), .id="trait") %>%
        mutate(samplesize = samplesize)
      
    })
    
    
    output$updatesize <- DT::renderDT(
      editedsize()
    )
    
  }
)