Change cells based on modifications of other cells in rhandsontable of a shiny app

Question

I am trying to build a shiny app with rhandsontable in it. This rhandsontable is based on the datframe I create inside the app.

In the app I initially display the first

Answer 1

In the code that you have added for retrieving the value selected in second column, we would need to update something.

if(col==0){
         values$postcode <- input$test$changes$changes[[1]][[4]]
         #values$car_group<-input$test$changes$changes[[1]][[4]]
      }

Index of handsontable starts with 0. So, its 0 for first column and 1 for second column, meaning you cannot update the values to car_group reactive variable within the if condition for the first column

A solution to your current question based on the answer that I provided here. Update rhandsontable by changing one cell value

library(shiny)
library(rhandsontable)


ui <- fluidPage(

   titlePanel("RHandsontable"),
   sidebarLayout(
      sidebarPanel(),
      mainPanel(
         rHandsontableOutput("test")
      )
   )
)


server <- function(input, output) {

  # Assigning blank values to reactive variable as all the values need to be listed first
  values <- reactiveValues(postcode = "",cargroup = "",tabledata = data.frame())

  observeEvent(values$postcode,{
    DF2 = data.frame(agency_postcode = factor(rep(c(12345,45678,24124,32525,32325),2)),
                     car_group=factor(rep(c("Microcar","City car","Supermini","Compact","SUV"),2)),
                     transmission=factor(rep(c("automatic","manual"),5)))
    # When the user selects any value from the dropdown, filter the table and update the value of reactive df
    if(values$postcode!=""){
      values$tabledata <- DF2[ which(DF2$agency_postcode ==values$postcode), ]
    }else{
      # When the postcode value is blank, meaning the user hasn't selected any, the table 
      # will render without the third column
      values$tabledata <- DF2[,-3]
    }

  })

  observeEvent(values$cargroup,{
    DF2 = data.frame(agency_postcode = factor(rep(c(12345,45678,24124,32525,32325),2)),
                     car_group=factor(rep(c("Microcar","City car","Supermini","Compact","SUV"),2)),
                     transmission=factor(rep(c("automatic","manual"),5)))
    values$tabledata <- DF2
    # When the user selects any value from the dropdown, filter the table and update the value of reactive df
    if(values$cargroup!=""){
      values$tabledata <- DF2[ which(DF2$car_group ==values$cargroup), ]
    }else{
      # When the cargroup value is blank, meaning the user hasn't selected any, the table 
      # will render without the third column
      values$tabledata <- DF2[,-3]
    }

  })

  # Observer for changes made to the hot
  observeEvent(input$test$changes$changes,{
    col <- input$test$changes$changes[[1]][[2]]
    # Changes made in first column
    if(col==0){
      values$postcode <- input$test$changes$changes[[1]][[4]]
    }
    # Changes made in second column
    if(col==1){
      values$cargroup <- input$test$changes$changes[[1]][[4]]
    }
  })

  # Render the hot object
  output$test <- renderRHandsontable({
    rhandsontable(values$tabledata[1,], rowHeaders = NULL, width = 550, height = 300)%>%
      hot_col(colnames(values$tabledata)) 
  })


}

shinyApp(ui = ui, server = server)

Check if this suits your needs. You can then update the observer part based on search button instead of being reactive to the changes made by user.