Shiny rhandsontable automatic values depending on User - r

Question

I have a table, in which the user will give as input some groups. As a result, I want another column to automatically update and show the frequency (or replicate) of each group:
This code creates this app:
library(shiny)
library(rhandsontable)
library(tidyverse)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("Automatic data rhandsontable"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
),
# Show a plot of the generated distribution
mainPanel(
rhandsontable::rHandsontableOutput('ed_out'),
shiny::actionButton('start_input', 'save final table')
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output) {
# This has to be reactive
data <- reactive({
df <- data.frame(Animal = c('Dog', 'Cat', 'Mouse', 'Elephant', 'Tiger'),
Group = ' ',
replicate = as.numeric(' '))
})
output$ed_out <- rhandsontable::renderRHandsontable({
df <- data()
rhandsontable(
df,
height = 500,
width = 600) %>%
hot_col('replicate', format = '0a', readOnly = TRUE) %>%
hot_col('Animal', readOnly = TRUE)
})
# This is just to save the table when the user has finished, can be ignored
group_finals <- reactiveValues()
observeEvent(input$start_input, {
group_finals$data <- rhandsontable::hot_to_r(input$ed_out)
print(group_finals$data)
}
)
}
# Run the application
shinyApp(ui = ui, server = server)
So the idea is that the user, inputs the groups and the replicate is automatically updated: (here the user gives as input B, B, A, A, B.
I am able to count the replicates of each group, but I'm not sure how where to implement this part to calculate them and display them at the same time after the user inputs each group.
df <- df %>%
group_by(Group) %>%
mutate(replicate = 1:n())
Not sure if this is the best approach, I tried a bit with the hot_to_col renderer to use javascript but I'm unfamiliar with that language.

Answer 1

Sorry but I'm not familiar with the tidyverse - so I switched to data.table.
hot_to_r is the right way to go:
library(shiny)
library(rhandsontable)
library(data.table)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("Automatic data rhandsontable"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
),
# Show a plot of the generated distribution
mainPanel(
rhandsontable::rHandsontableOutput('ed_out'),
shiny::actionButton('start_input', 'save final table')
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output) {
# This has to be reactive
data <- reactive({
data.frame(Animal = c('Dog', 'Cat', 'Mouse', 'Elephant', 'Tiger'),
Group = '',
replicate = NA_integer_)
})
myData <- reactiveVal()
observeEvent(data(),{
myData(data())
})
output$ed_out <- rhandsontable::renderRHandsontable({
rhandsontable(
myData(),
height = 500,
width = 600) %>%
hot_col('replicate', format = '0a', readOnly = TRUE) %>%
hot_col('Animal', readOnly = TRUE)
})
observeEvent(input$ed_out, {
userDT <- rhandsontable::hot_to_r(input$ed_out)
setDT(userDT)
userDT[, replicate := seq_len(.N), by = Group][is.na(Group) | Group == "", replicate := NA_integer_]
myData(userDT)
})
# This is just to save the table when the user has finished, can be ignored
group_finals <- reactiveValues()
observeEvent(input$start_input, {
group_finals$myData <- rhandsontable::hot_to_r(input$ed_out)
print(group_finals$myData)
})
}
# Run the application
shinyApp(ui = ui, server = server)