R Shiny 将 SelectizeInput 默认值设置为 NULL

Question

我尝试让下面的代码工作。但 selectizeInput 小部件的默认值并不像我预期的那样为 NULL。之前，当我允许多个输入时，默认设置有效（NULL）。但这次我需要一个选择输入。有人有建议吗？

       selectizeInput("request","Select Existing Request",
               choice = unique(fileNames),multiple = FALSE,
               selected = NULL)

Answer 1

试试这个：

library(shiny)

fileNames = c('a', 'b', 'c', 'd', 'e')

ui <- fluidPage(
  selectInput("request","Select Existing Request",
                 choice = c('Choose a File Name' = '', unique(fileNames)), multiple = FALSE,
                 selected = NULL)
)

server <- function(input, output) {

}

shinyApp(ui = ui, server = server)