Question

应该很容易防止“伦敦”出现在页面顶部，但我找不到方法。

library(shiny)
ui <- fluidPage(
    mainPanel(
        mylist <- c("London","Paris"), 
        selectInput("s", "Select", mylist)
        )
    )
server <- function(input, output) {}
shinyApp(ui = ui, server = server)

Answer 1

将我的清单从FluidPage中移除：

library(shiny)
mylist <- c("London","Paris")
ui <- fluidPage(
  mainPanel( 
    selectInput("s", "Select", mylist)
  )
)
server <- function(input, output) {}
shinyApp(ui = ui, server = server)

否则，mylist作为另一个输出（如标头）包含在mainPanel函数中。

当然，作为替代方案，您可以直接在selectInput中包含选项列表，并完全省略mylist向量：

selectInput("s", "Select", choices = c("London","Paris"))

Answer 2

您可以将向量直接用于selectInput内部，例如：

library(shiny)
ui <- fluidPage(
  mainPanel( 
    selectInput("s", "Select", choices = c("London","Paris"))
  )
)
server <- function(input, output) {}
shinyApp(ui = ui, server = server)

如果您必须根据选择在选项中使用一些静态验证，则可以使用以下方式：

library(shiny)
library(shinyalert)
ui <- fluidPage(
  mainPanel( 
    useShinyalert(),
    selectInput("option_select", "Select", choices = c("London"="lon","Paris"="par")),
    actionButton("check_city","City Selected")
  )
)
server <- function(input, output) {

  observeEvent(input$check_city,{
      if(input$option_select=="lon")
      {
       shinyalert("City Selected:  London")
      }
      else
      {
        shinyalert("City Selected:  Paris")
      }
  })
}
shinyApp(ui = ui, server = server)

如何阻止代码显示在Shiny UI中？

2 个答案: