我有一个 Shiny 应用程序，我希望用户能够选择多个选项 - 但只能达到一定的限制。我找不到限制数量的方法。
下面是一个简单的、可重现的示例。在其中，我的用户只能为第一个问题选择最多 2/4 个选项，为第二个问题选择最多 3/4 个选项，为第三个问题选择任意数量的选项(问题无需编辑) 3).
library(shiny)
ui <- fluidPage(
sidebarLayout(
sidebarPanel( selectInput("q1", label = "Choose up to 2.", choices = c(" ", "option 1", "option 2", "option 3", "option 4"), multiple = TRUE),
selectInput("q2", label = "Choose up to 3.", choices = c(" ", "option 1", "option 2", "option 3", "option 4"), multiple = TRUE),
selectInput("q3", label = "Choose as many as you want.", choices = c(" ", "option 1", "option 2", "option 3", "option 4"), multiple = TRUE)),
mainPanel(
)
)
)
server <- function(input, output) {
}
# Run the application
shinyApp(ui = ui, server = server)
最佳答案
您可以使用 selectizeInput 代替 selectInput，并使用 options 参数使用 maxItems 设置允许的最大项目数。
library(shiny)
ui <- fluidPage(sidebarLayout(
sidebarPanel(
selectizeInput(
"q1",
label = "Choose up to 2.",
choices = c(" ", "option 1", "option 2", "option 3", "option 4"),
multiple = TRUE,
options = list(maxItems = 2)
),
selectizeInput(
"q2",
label = "Choose up to 3.",
choices = c(" ", "option 1", "option 2", "option 3", "option 4"),
multiple = TRUE,
options = list(maxItems = 3)
),
selectInput(
"q3",
label = "Choose as many as you want.",
choices = c(" ", "option 1", "option 2", "option 3", "option 4"),
multiple = TRUE
)
),
mainPanel()
))
server <- function(input, output) {
}
# Run the application
shinyApp(ui = ui, server = server)
关于r - 当 multiple 为 true 时，如何限制用户可以使用 R Shiny 的 selectInput 选择的选项数量？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/69317783/