rhandsontable Shiny App: Button that fills a given column with vector values

Question

I would like to prepare a Shiny App in which the user can fill one column (e.g. Col1) with numbers and then press a button to generate entries for Col2 (a transformation of values introduced to Col1, e.g. multiply each row of Col1 by a random number). How should I add the button to the following sample code:

library(rhandsontable)
library(shiny)
# add a sparkline chart
DF$chart = sapply(1:10, function(x) jsonlite::toJSON(list(values=rnorm(10))))
rhandsontable(DF, rowHeaders = NULL) %>%
  hot_col("chart", renderer = htmlwidgets::JS("renderSparkline"))

editTable <- function(DF, outdir=getwd(), outfilename="table"){
  ui <- shinyUI(fluidPage(
  titlePanel("Edit and save a table"),
    sidebarLayout(
      sidebarPanel(
        helpText("Shiny app based on an example given in the rhandsontable package.", 
                 "Right-click on the table to delete/insert rows.", 
                 "Double-click on a cell to edit"),

 wellPanel(
          h3("Table options"),
          radioButtons("useType", "Use Data Types", c("TRUE", "FALSE"))
        ),
        br(), 

 wellPanel(
          h3("Save"), 
          actionButton("save", "Save table")
        ),    

        wellPanel(
          textOutput('result')
        ) 
      ),

      mainPanel(
         rHandsontableOutput("hot")
      )
    )
    ))
   server <- shinyServer(function(input, output) {

    values <- reactiveValues()

    ## Handsontable
    observe({
      if (!is.null(input$hot)) {
        DF = hot_to_r(input$hot)
      } else {
        if (is.null(values[["DF"]]))
          DF <- DF
        else
          DF <- values[["DF"]]
      }
      values[["DF"]] <- DF
    })

    output$hot <- renderRHandsontable({
      DF <- values[["DF"]]
      if (!is.null(DF))
        rhandsontable(DF, useTypes = as.logical(input$useType), stretchH = "all")
    })

    ## Save 
    observeEvent(input$save, {
      finalDF <- isolate(values[["DF"]])
      saveRDS(finalDF, file=file.path(outdir, sprintf("%s.rds", outfilename)))
    })

  })

  ## run app 
  runApp(list(ui=ui, server=server))
  function(input, output)
    return(invisible())
}

( DF <- data.frame(Col1=1:10, Col2=runif(10), stringsAsFactors = FALSE))

editTable(DF)

Answer 1

Are you looking for something like that:

  ui <- shinyUI(fluidPage(
    titlePanel("Edit and save a table"),
    sidebarLayout(
      sidebarPanel(
        helpText("Shiny app based on an example given in the rhandsontable package.", 
                 "Right-click on the table to delete/insert rows.", 
                 "Double-click on a cell to edit"),          
        wellPanel(
          h3("Table options"),
          radioButtons("useType", "Use Data Types", c("TRUE", "FALSE")),
          actionButton("Calculate", "Calculate column 2")
        ),
        br(),           
        wellPanel(
          h3("Save"), 
          actionButton("save", "Save table")
        ),              
        wellPanel(
          textOutput('result')
        ) 
      ),

      mainPanel(
        rHandsontableOutput("hot")
      )
    )
  ))

  server <- shinyServer(function(input, output) {       
    #extract data from the table to be used
    portfoliovals2 <- reactive({
      live_data = hot_to_r(input$hot)[,1]
      return(live_data)
    })      
    #extract data to be used
    portfoliovalsB2 <- reactive({
      live_data = hot_to_r(input$hot)[,2]
      return(live_data)
    })


    ## create a new df every time the table is modified 
    new_df_g <- reactive({
      initial_dataEdit = portfoliovals2()
      initial_dataEditB = portfoliovalsB2()
      initial_dataEditW <- data.frame(initial_dataEdit, initial_dataEditB)    
      return(initial_dataEditW)
    })

    output$hot <- renderRHandsontable({

      if (input$Calculate ==0){
        initial_data = data.frame(Col1=1:10, Col2=runif(10), stringsAsFactors = FALSE)

      } else {
        initial_data = new_df_g()
        initial_data <- plyr::rename(initial_data, c("initial_dataEdit"="Col1", "initial_dataEditB"="Col2"))

        initial_data$Col2 <- initial_data$Col1 * 1.3
      }

      rhandsontable(initial_data, readOnly = FALSE,  rowHeaders = NULL, height = 600) %>%
        hot_cols(columnSorting = TRUE)
    })
  })

    ## Save 
    observeEvent(input$save, {
      finalDF <- new_df_g() 
      saveRDS(finalDF, file=file.path(outdir, sprintf("%s.rds", outfilename)))
    })

  })

  ## run app 
  runApp(list(ui=ui, server=server))