How to add rows to R Shiny table - r

Question

I am trying to build a form with R Shiny which will be used to populate a table once the action button at the end of the form is clicked. What I have not been able to figure out is how to pick up the data in the form and add it to a new row in the table. Right now, it just keeps updating the first row with whatever is in the form. I have reproduced a simple version of the code here:
#ui.r
library(shiny)
shinyUI(fluidPage(
# Application title
titlePanel("Test App"),
sidebarPanel(
numericInput("x", "Enter Value of X", 1),
numericInput("y", "Enter Value of Y", 1),
actionButton("add_data", "Add Data", width="100%")
),
mainPanel(
tableOutput("xy_Table")
)
)
)
#server.R
library(shiny)
library(tidyverse)
shinyServer(function(input, output) {
x <- vector("numeric")
y <- vector("numeric")
xyTable <- tibble(x, y)
e <- reactive(input$x)
f <- reactive(input$y)
eventReactive(input$add_data, {
xyTable %>% add_row(x=e(), y=f())
})
output$xy_Table <- renderTable({
xyTable
})
})
Thanks a lot for any help.

Answer 1

You need to use a reactive xyTable in order for the output to update. Also,
append the rows inside an observer rather than a reactive expression, and make sure to save the updated reactive value:
library(shiny)
library(tidyverse)
ui <- fluidPage(
sidebarPanel(
numericInput("x", "Enter Value of X", 1),
numericInput("y", "Enter Value of Y", 1),
actionButton("add_data", "Add Data", width = "100%")
),
mainPanel(
tableOutput("xy_Table")
)
)
server <- function(input, output, session) {
xyTable <- reactiveVal(
tibble(x = numeric(), y = numeric())
)
observeEvent(input$add_data, {
xyTable() %>%
add_row(
x = input$x,
y = input$y,
) %>%
xyTable()
})
output$xy_Table <- renderTable(xyTable())
}
shinyApp(ui, server)

Answer 2

Try this:
library(shiny)
library(tidyverse)
#ui.r
ui <- fluidPage(
# Application title
titlePanel("Test App"),
sidebarPanel(
numericInput("x", "Enter Value of X", 1),
numericInput("y", "Enter Value of Y", 1),
actionButton("add_data", "Add Data", width = "100%")
),
mainPanel(
tableOutput("xy_Table")
)
)
#server.R
server <- function(input, output) {
xyTable <- reactiveValues(
table1 = tibble(x = numeric(), y = numeric())
)
# what happens when `add_data` is clicked?
observeEvent(input$add_data, {
xyTable$table1 <- xyTable$table1 |>
add_row(x = input$x, y = input$y)
})
output$xy_Table <- renderTable({
xyTable$table1
})
}
shinyApp(ui, server)

Answer 3

#ui.r
library(shiny)
ui <- shinyUI(fluidPage(
# Application title
titlePanel("Test App"),
sidebarPanel(
numericInput("x", "Enter Value of X", 1),
numericInput("y", "Enter Value of Y", 1),
actionButton("add_data", "Add Data", width="100%")
),
mainPanel(
tableOutput("xy_Table")
)
)
)
#server.R
library(shiny)
library(tidyverse)
server <- shinyServer(function(input, output) {
x <- vector("numeric")
y <- vector("numeric")
xyTable <- reactiveValues()
xyTable$df <- tibble(x, y)
e <- reactive(input$x)
f <- reactive(input$y)
observeEvent(input$add_data, {
xyTable$df <- xyTable$df %>% add_row(x=e(), y=f())
})
output$xy_Table <- renderTable({
xyTable$df
})
})
shinyApp(ui,server)