How to access dynamic created rhandsontable values and do calculations in R Shiny?

Question

I am trying to make an app which can dynamically create multiple tabs with tables in the 1st tab (Input tab), and use the dynamically created tables to do calculations in the 2nd tab (Results tab). However, I am not sure how to use the hot_to_r function to access the values from the tables created in the Input tab to do calculations in the Results tab. As an example, I want to take column i+1 divide by column i in the tables in the Input tab and display the results in the Results tab.

Below are the sample codes:

library(shiny)
library(rhandsontable)

ui <- navbarPage("App",
                   
                 tabPanel("Input",
                          numericInput('num_of_table', "Number of sub tabs: ", value = 1, min = 1, max = 10),
                          uiOutput("input")),
                 
                 tabPanel("Results",
                          uiOutput("results"))
                   
)

server <- function(input, output,session) {
  
 ### Input ### 
  
  input_table<- reactive({
    list_of_input_table = list()
    
    for (i in c(1:input$num_of_table)){
      mat <- matrix(c(1:25) * i, ncol = 5, nrow = 5)
      list_of_input_table[[i]] = mat
    }
    
    index = c(1:i)
    list_of_input_table[index]
  })
  
  observeEvent(input$num_of_table, {
    lapply(seq_len(input$num_of_table), function(i) {
      output[[paste0('input_table_', i)]] <- renderRHandsontable({
        
        rhandsontable(input_table()[[i]])
      })
    })
  })
  
  output$input <- renderUI({
    
    nTabs = input$num_of_table
    
    myTabs1 = lapply(seq_len(nTabs), function(x){
      tabPanel(paste("Tab", x),
               column(12,
                      rHandsontableOutput(paste0("input_table_", x))))
    })
    do.call(tabsetPanel, myTabs1)
    
  })
  
  ### Results ###
  
  results_table<- reactive({
    list_of_results_table = list()
    list_of_input_table = list()
    
    for (i in c(1:input$num_of_table)){
      for (j in c(1:5)) {
          
        list_of_input_table[[i]] <- as.matrix(hot_to_r(input[[paste0("input_table_",i)]]))
        list_of_results_table[[i]] <- matrix(as.numeric(NA), ncol = 4, nrow = 5)
        list_of_results_table[[i]][,j] <- list_of_input_table[[i]][,j+1][!is.null(list_of_input_table[[i]][,j+1])] / list_of_input_table[[i]][,j]
      
    }}
    
    index = c(1:i)
    list_of_results_table[index]
  })
  
  
  observeEvent(input$num_of_table, {
    lapply(seq_len(input$num_of_table), function(i) {
      output[[paste0('results_table_', i)]] <- renderRHandsontable({
        
        rhandsontable(results_table()[[i]])
      })
    })
  })
  
  output$results <- renderUI({
    
    nTabs = input$num_of_table
    
    myTabs2 = lapply(seq_len(nTabs), function(x){
      tabPanel(paste("Tab", x),
               column(12,
                      rHandsontableOutput(paste0("results_table_", x))))
    })
    do.call(tabsetPanel, myTabs2)
    
  })
}


shinyApp(ui,server)

Please help!!

ismirsehregal · Accepted Answer · 2020-07-07T11:48:39.913

It seems hot_to_r isn't handling matrix objects correctly in this case.

Please check the following using a data.frame instead:

library(shiny)
library(rhandsontable)

ui <- navbarPage("App",
                 
                 tabPanel("Input",
                          numericInput('num_of_table', "Number of sub tabs: ", value = 1, min = 1, max = 10),
                          uiOutput("input")),
                 
                 tabPanel("Results",
                          uiOutput("results"))
                 
)

server <- function(input, output,session) {
  
  ### Input ### 
  input_table <- reactive({
    list_of_input_table = list()
    
    for (i in c(1:input$num_of_table)){
      mat <- matrix(c(1:25) * i, ncol = 5, nrow = 5)
      list_of_input_table[[i]] = as.data.frame(mat)
    }
    
    index = c(1:i)
    list_of_input_table[index]
  })
  
  observeEvent(input$num_of_table, {
    lapply(seq_len(input$num_of_table), function(i) {
      output[[paste0('input_table_', i)]] <- renderRHandsontable({
        rhandsontable(input_table()[[i]])
      })
    })
  })
  
  output$input <- renderUI({
    
    nTabs = input$num_of_table
    
    myTabs1 = lapply(seq_len(nTabs), function(x){
      tabPanel(paste("Tab", x),
               column(12,
                      rHandsontableOutput(paste0("input_table_", x))))
    })
    do.call(tabsetPanel, myTabs1)
    
  })
  
  ### Results ###
  results_table <- reactive({
    
    list_of_results_table = list()
    for (i in c(1:input$num_of_table)){
      req(input[[paste0("input_table_", i)]])
      list_of_results_table[[i]] <- hot_to_r(input[[paste0("input_table_", i)]])[2:5]/hot_to_r(input[[paste0("input_table_", i)]])[1:4]
      }
    return(list_of_results_table)
  })
  
  
  observeEvent(input$num_of_table, {
    lapply(seq_len(input$num_of_table), function(i) {
      output[[paste0('results_table_', i)]] <- renderRHandsontable({
        
        rhandsontable(results_table()[[i]])
      })
    })
  })
  
  output$results <- renderUI({
    
    nTabs = input$num_of_table
    
    myTabs2 = lapply(seq_len(nTabs), function(x){
      tabPanel(paste("Tab", x),
               column(12,
                      rHandsontableOutput(paste0("results_table_", x))))
    })
    do.call(tabsetPanel, myTabs2)
    
  })
}


shinyApp(ui,server)

I filed an issue here.

Thanks for your help @ismirsehregal ! – debster Jul 07 '20 at 13:42 — debster, Jul 07 '20 at 13:42

How to access dynamic created rhandsontable values and do calculations in R Shiny?

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