An example for you
library(shiny)
ui <- fluidPage(
uiOutput("u_selector"),
p("first 10 values are : "),
verbatimTextOutput("result")
)
server <- function(input, output, session) {
df <- reactive(iris)
output$u_selector <- renderUI({
df_local <- req(df())
selectInput("user_selected","make a selection",
choices=names(df_local),
selected = names(df_local)[[1]])
})
output$result <- renderText({
df_local <- req(df())
u_sel <- req(input$user_selected)
dfh <- head(df_local,n=10)
dfh[[u_sel]]
})
}
shinyApp(ui, server)