CODEWITHSUNDEEP
rshiny
PeterJ
PeterJ

Reputation: 79

How to sequentially add new choices to selectizeInput?

I'm new to R and Shiny and I'm trying to work out how to allow the user to add new 'choices' to a selection list one at a time. e.g. if the user uploads datasets one at a time, the names of all the datasets would then be available for selection in the selection list.

I have done the simple version (see below), where a user can add a single new 'choice' to the list. But it obviously does not save each new choice when you keep adding new choices.

My attempt at adding more than 1 new choice is also below.

#### Simple working version of adding 1 new choice ####
choices <- c("x", "y", "z")

ui <- fluidPage(
    selectizeInput("choices","Choices", choices = choices, multiple = TRUE),
    textInput("new_choices", "New choices to add"),
    actionButton("add_choices", "Add new choices")
)

server <- function(input, output,session) {

    observeEvent(input$add_choices, {
        req(input$new_choices)
        choices <- c(choices, input$new_choices)
        updateSelectizeInput(session, "choices", choices = choices)
    })

}

shinyApp(ui = ui, server = server)



#### Not working version of sequentially adding new choices ####
choices <- c("x", "y", "z")

ui <- fluidPage(
    selectizeInput("choices","Choices", choices = choices, multiple = TRUE),
    textInput("new_choices", "New choices to add"),
    actionButton("add_choices", "Add new choices")
)

server <- function(input, output,session) {

    temp <- reactive({
        choices
    })

    update_choices <- function() {
        temp <- reactive({
            c(temp, input$new_choices)
        })
        return(temp)
    }

    observeEvent(input$add_choices, {
        req(input$new_choices)
        temp <- update_choices()
        updateSelectizeInput(session, "choices", choices = temp)
    })

}

shinyApp(ui = ui, server = server)

The non-working code results in this: Warning: Error in as.vector: cannot coerce type 'closure' to vector of type 'list' [No stack trace available]

Upvotes: 2

Views: 76

Answers (1)

Daniel Fischer
Daniel Fischer

Reputation: 973

Just add a reactive value with the choices

library(shiny)

ui <- fluidPage(
  selectizeInput("choices","Choices", choices = c(), multiple = TRUE),
  textInput("new_choices", "New choices to add"),
  actionButton("add_choices", "Add new choices")
)

server <- function(input, output,session) {

  values = reactiveValues()
  values$current_choices = c("x", "y", "z")

  observeEvent(input$add_choices, {
    req(input$new_choices)
    values$current_choices <- c(values$current_choices, input$new_choices)
  })

  observe({
    updateSelectizeInput(session, "choices", choices = values$current_choices, selected = input$choices)
  })

}

shinyApp(ui = ui, server = server)

Upvotes: 1

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