闪亮 - 更改 selectInput() 中的选项数量

Question

我想更改 selectInput() 中的选项数。如果新选择的数量与原始选择的数量相等，则以下 reprex 有效，但如果提供了更多（或更少）选择，则代码不起作用。我怎样才能变得闪亮，不仅接受 selectInput() 的新选择，而且接受新的选择数量？在此先感谢您的帮助。

菲利普


    library(shiny)
    ui <- fluidPage(
      tabPanel("tbls",
        selectInput("tab1",label="Pick a table:",choices=c("a","b","c")),
        selectInput("cht1",label="Pick a time series:",choices=c("d","e","f"))
      )
    )
    server <- function(input,output,session) {
      Nchoices <- reactive({case_when(
        input$tab1=="a" ~c("d","e","f"),
        input$tab1=="b" ~c("g","h","i"),
        input$tab1=="c" ~c("j","k","l","m") # adding one more choice breaks the code
      )}) 
      observe({updateSelectInput(session,"cht1",
        label="Pick a time series:",choices=Nchoices(),selected=NULL)})
      observe(print(Nchoices()))
    
    }
    shinyApp(ui, server)

Answer 1

尝试使用 switch 而不是 case_when。此外，renderUI 可能会有用。试试这个

library(shiny)
ui <- fluidPage(
  tabPanel("tbls",
           selectInput("tab1",label="Pick a table:",choices=c("a","b","c")),
           uiOutput("myselect")
           #selectInput("cht1",label="Pick a time series:",choices=c("d","e","f"))
  )
)
server <- function(input,output,session) {
  
  Nchoices <- reactive({
    switch(input$tab1, 
           "a" = c("d","e","f"),
           "b" = c("g","h"),
           "c" = c("j","k","l","m") # adding one more choice breaks the code
    )
  })
  
  output$myselect <- renderUI({
    req(input$tab1)
    selectInput("cht1",label="Pick a time series:",choices=Nchoices())
  })
 
  observe(print(Nchoices()))
  
}
shinyApp(ui, server)

请注意，在 case_when 中，所有 RHS 值都必须是同一类型。不一致的类型将引发错误。

闪亮 - 更改 selectInput() 中的选项数量

Shiny - Changing the number of choices in selectInput()

r

shiny

selectinput