r - Shiny 的应用程序中的多个 group_by

Question

我有一个 Shiny 的应用程序，它接受一个数据帧，并应用 group_by 中的 dplyr 。我可以让它接受单个组，但我希望 selectInput 接受多个分组变量。

我可以通过添加另一个 selectInput ，然后将其传递给 group_by 语句来解决这个问题，但我希望将其扩展到任意数量的变量。因此，我需要单个 selectInput 来接受多个参数。

仅添加 multiple = TRUE 不会以 group_by 理解的方式传递变量，并且 this answer 由于 group_by_ 已弃用，我无法适应

笔记，

此应用程序的完整版本使用 fileInput ，而不是硬编码数据集，因此调用 renderUI 和 reactive

library(shiny)
library(DT)
library(dplyr)

ui <- fluidPage(

  titlePanel("app"),

  sidebarLayout(
    sidebarPanel(

      uiOutput("groups")

    ),


    mainPanel(

      DT::dataTableOutput("summary")
    )
  )
)


server <- function(input, output) {
  mydata <- reactive({structure(list(School = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 
                                                          2L, 1L, 1L, 2L, 2L), .Label = c("School1", "School2"), class = "factor"), 
                                     Town = structure(c(1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 2L, 1L, 
                                                        2L, 1L), .Label = c("Levin", "Wellington"), class = "factor"), 
                                     Income = c(6314L, 3546L, 3541L, 846684L, 231123L, 564564L, 
                                                545L, 1325L, 484L, 51353L, 465546L, 564546L)), .Names = c("School", 
                                                                                                          "Town", "Income"), class = "data.frame", row.names = c(NA, -12L
                                                                                                          ))})



  output$groups <- renderUI({
    df <- mydata()
    selectInput(inputId = "grouper", label = "Group variable", choices = names(df), multiple = TRUE)
  })




  summary_data <- reactive({
    req(input$grouper)
    mydata() %>%
      dplyr::group_by(!!rlang::sym(input$grouper)) %>%
      dplyr::summarise(mean_income = mean(Income), na.rm = TRUE)
  })

  output$summary <- DT::renderDataTable({
    DT::datatable(summary_data())
  })



}

shinyApp(ui, server)

Answer 1

正如 Renu 在评论中指出的，答案是用 !! 替换 !!! ，用 sym 替换 syms (这允许 group_by 接受变量列表，而不是单个变量。

library(shiny)
library(DT)
library(dplyr)

ui <- fluidPage(

  titlePanel("app"),

  sidebarLayout(
    sidebarPanel(

      uiOutput("groups")

    ),


    mainPanel(

      DT::dataTableOutput("summary")
    )
  )
)


server <- function(input, output) {
  mydata <- reactive({structure(list(School = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 
                                                          2L, 1L, 1L, 2L, 2L), .Label = c("School1", "School2"), class = "factor"), 
                                     Town = structure(c(1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 2L, 1L, 
                                                        2L, 1L), .Label = c("Levin", "Wellington"), class = "factor"), 
                                     Income = c(6314L, 3546L, 3541L, 846684L, 231123L, 564564L, 
                                                545L, 1325L, 484L, 51353L, 465546L, 564546L)), .Names = c("School", 
                                                                                                          "Town", "Income"), class = "data.frame", row.names = c(NA, -12L
                                                                                                          ))})



  output$groups <- renderUI({
    df <- mydata()
    selectInput(inputId = "grouper", label = "Group variable", choices = names(df), multiple = TRUE)
  })




  summary_data <- reactive({
    req(input$grouper)
    mydata() %>%
      dplyr::group_by(!!!rlang::syms(input$grouper)) %>%
      dplyr::summarise(mean_income = mean(Income), na.rm = TRUE)
  })

  output$summary <- DT::renderDataTable({
    DT::datatable(summary_data())
  })



}

shinyApp(ui, server)