Return a table from R shiny observe() - r

Question

I want to create a vector by using observe() in R shiny. In the code blow, how can I create a vactor where all the input$n are concatenated. At the present time, I can only display a single value but could not concatenate and display all the inputs from the sliderInput.
ui.R
library(shiny)
fluidPage(
titlePanel("Observer demo"),
fluidRow(
column(4, wellPanel(
sliderInput("n", "N:",
min = 10, max = 1000, value = 200, step = 10)
)),
column(8,
tableOutput("text")
)
)
)
server.R
library(shiny)
function(input, output, session) {
observed=reactiveValues(
input=NULL
)
observe({
observed$input=input$n
# observed$input=c(observed$input,input$n) # tried this but not working
})
output$text <- renderTable({
observed$input
})
}

Answer 1

If you add print(observed$input) in your observer, you will see that when you use observed$input=c(observed$input,input$n) you run into an infinite loop as the observe is reactive to observe$input and will run again as soon as you modify it.
To prevent this, you can use isolate:
observed$input=c(isolate(observed$input),input$n)
As in #Pork Chop 's answer, you can also use observeEvent to only observe input$n.

Answer 2

Try this, you can use cbind or rbind depending on your needs
rm(list = ls())
library(shiny)
ui <- fluidPage(
titlePanel("Observer demo"),
fluidRow(
column(4, wellPanel(
sliderInput("n", "N:",
min = 10, max = 1000, value = 200, step = 10)
)),
column(8,
tableOutput("text")
)
)
)
server <- function(input, output, session) {
observed=reactiveValues(
input=NULL
)
observeEvent(input$n,{
observed$input <- cbind(observed$input,input$n)
})
output$text <- renderTable({
print(observed$input)
observed$input
})
}
shinyApp(ui <- ui, server <- server)