R Shiny Radio Buttons not Updating with updateRadioButtons - r

Question

I'm working on a quiz type program in Shiny, which needs to have radio buttons that update with answers from a table. I have the code below, but the radio buttons don't update, and the answers remain 2, 3, 4, 5, and 6 despite changing questions. Any ideas on why this might be happening, and what would fix this?
library(shiny)
ui <- fluidPage(
selectInput("numberchoice",label = "Choose an image", choices = c(1:6), selected = 1)
,
imageOutput("image")
,
radioButtons("answerchoice", "Answers", choices = c(2:6))
)
server <- function(input,output,session) {
answers <- read.csv("~/Answers.csv")
questions <- read.csv("~/Answers.csv")
output$image <- renderImage(list(src = paste("~",".png", sep = "")
,contentType = "image/png", alt = "Face"),deleteFile = FALSE)
eventReactive(input$numberchoice,{updateRadioButtons(session,"answerchoice",choices = questions[input$numberchoice,2:6])})
}
shinyApp(ui = ui, server = server)

Answer 1

Try replacing eventReactive with observeEvent. The following code works for me.
library(shiny)
ui <- fluidPage(
selectInput("numberchoice", label = "Choose an image", choices = 1:6, selected = 1),
radioButtons("answerchoice", "Answers", choices = 1:6 )
)
server <- function(input, output, session) {
observeEvent(input$numberchoice,{
updateRadioButtons(session, "answerchoice",
choices = letters[1:input$numberchoice])})
}
shinyApp(ui = ui, server = server)
It seems like eventReactive didn't trigger so updateRadioButtons was not the problem.