javascript - 如何从 R Shiny 应用程序中数据表中的选定行获取行值

Question

我需要从 DT 数据表中获取所选行第一列的值。使用 DataTable_rows_selected ，我可以获得选定的行数，现在我正在寻找从数据表中提取行值的方法。在下面的示例中，有两个基于操作按钮的observeEvent，第一个观察事件是导入并显示数据，第二个需要显示所选行的第一个列值，以便我可以使用相同的实现其他特性。请注意，在实际应用中，导入的数据是一个Web服务API，我正在R中解析它并转换为数据帧。

示例:

library(shiny)
library(shinydashboard)
library(DT)

ui <- dashboardPage(
dashboardHeader(title = "Data Table Example"),
dashboardSidebar(
sidebarMenu(
  menuItem('Tabs', tabName='tabs',
           menuSubItem('Tab 1', tabName='tab1'),
           menuSubItem('Tab 2', tabName='tab2')
  )
)
),

dashboardBody(

tabItems(
  tabItem(tabName='tab1',
          actionButton("import","Import"),
          br(),
          tags$div(tags$h3(tags$b(" Get Selected Row Values",align="middle",style="color: rgb(57,156,8)"))),
          br(),
          DT::dataTableOutput('ProductDataTable')
  ),
  tabItem(tabName='tab2',
          actionButton("display","Display"),
          uiOutput('info')
   )
 )
 )
 )

server <- function(input, output) {

observeEvent(input$import,{

Product <- read.csv2("RulesData.csv", header=TRUE, sep=";")

output$ProductDataTable <- DT::renderDataTable({

DT::datatable(Product,selection = "single",

                extensions = c('Buttons', 'ColReorder', 'FixedHeader', 'Scroller'),
                rownames=FALSE,
                options=list(dom = 'Bfrtip',
                             searching = T,
                             pageLength = 25,
                             searchHighlight = TRUE,
                             colReorder = TRUE,
                             fixedHeader = TRUE,
                             filter = 'bottom',
                             buttons = c('copy', 'csv','excel', 'print'),
                             paging    = TRUE,
                             deferRender = TRUE,
                             scroller = TRUE,
                             scrollX = TRUE,
                             scrollY = 700

                ))
})

})

observeEvent(input$display,{

row_count <- input$ProductDataTable_rows_selected

output$info <- renderPrint({

  cat('Row Selected: ')
  cat(row_count, sep = ', ')
  cat(Product[1,2], sep = ', ')


 })

})
}

shinyApp(ui, server)

Answer 1

如果这是您正在寻找的内容，请检查下面的代码:

library(shiny)
library(shinydashboard)
library(DT)

ui <- dashboardPage(
  dashboardHeader(title = "Data Table Example"),
  dashboardSidebar(
    sidebarMenu(
      menuItem('Tabs', tabName='tabs',
               menuSubItem('Tab 1', tabName='tab1'),
               menuSubItem('Tab 2', tabName='tab2')
      )
    )
  ),

  dashboardBody(

    tabItems(
      tabItem(tabName='tab1',
              actionButton("import","Import"),
              br(),
              tags$div(tags$h3(tags$b(" Get Selected Row Values",align="middle",style="color: rgb(57,156,8)"))),
              br(),
              DT::dataTableOutput('ProductDataTable')
      ),
      tabItem(tabName='tab2',
              actionButton("display","Display"),
              uiOutput('info')
      )
    )
  )
)

server <- function(input, output) {

  Product <- reactive({mtcars})

  observeEvent(input$import,{


    output$ProductDataTable <- DT::renderDataTable({

      DT::datatable(Product(),selection = "single",

                    extensions = c('Buttons', 'ColReorder', 'FixedHeader', 'Scroller'),
                    rownames=FALSE,
                    options=list(dom = 'Bfrtip',
                                 searching = T,
                                 pageLength = 25,
                                 searchHighlight = TRUE,
                                 colReorder = TRUE,
                                 fixedHeader = TRUE,
                                 filter = 'bottom',
                                 buttons = c('copy', 'csv','excel', 'print'),
                                 paging    = TRUE,
                                 deferRender = TRUE,
                                 scroller = TRUE,
                                 scrollX = TRUE,
                                 scrollY = 700

                    ))
    })

  })

  observeEvent(input$display,{


    output$info <- renderPrint({
      row_count <- input$ProductDataTable_rows_selected
      data <- Product()[row_count, ] 
      cat('Row Selected: ')
      cat(data[,1]) #display the selected row 1st col value  


    })

  })
}

shinyApp(ui, server)

我使用了mtcars数据集作为示例，问题是您的数据位于观察者内部(一个带有input$import )并且由于您需要将其用于其他分析，例如显示第一列的行值(我不太明白您的意思，因为您的代码正在讲述不同的事情)，因此数据必须移至observer 并放入 reactive 中。

[更新]

我使用了 if 语句而不是 observeEvent 来导入数据

library(shiny)
library(shinydashboard)
library(DT)

ui <- dashboardPage(
  dashboardHeader(title = "Data Table Example"),
  dashboardSidebar(
    sidebarMenu(
      menuItem('Tabs', tabName='tabs',
               menuSubItem('Tab 1', tabName='tab1'),
               menuSubItem('Tab 2', tabName='tab2')
      )
    )
  ),

  dashboardBody(

    tabItems(
      tabItem(tabName='tab1',
              actionButton("import","Import"),
              br(),
              tags$div(tags$h3(tags$b(" Get Selected Row Values",align="middle",style="color: rgb(57,156,8)"))),
              br(),
              DT::dataTableOutput('ProductDataTable')
      ),
      tabItem(tabName='tab2',
              actionButton("display","Display"),
              uiOutput('info')
      )
    )
  )
)

server <- function(input, output) {

  Product <- reactive({
    if(input$import == 0)
  {
    return()
  }
    isolate({
      input$import
      data <- mtcars # Here read Your data: read.csv2("RulesData.csv", header=TRUE, sep=";")
      })
  })


    output$ProductDataTable <- DT::renderDataTable({

      DT::datatable(Product(),selection = "single",

                    extensions = c('Buttons', 'ColReorder', 'FixedHeader', 'Scroller'),
                    rownames=FALSE,
                    options=list(dom = 'Bfrtip',
                                 searching = T,
                                 pageLength = 25,
                                 searchHighlight = TRUE,
                                 colReorder = TRUE,
                                 fixedHeader = TRUE,
                                 filter = 'bottom',
                                 buttons = c('copy', 'csv','excel', 'print'),
                                 paging    = TRUE,
                                 deferRender = TRUE,
                                 scroller = TRUE,
                                 scrollX = TRUE,
                                 scrollY = 700

                    ))
    })


  observeEvent(input$display,{


    output$info <- renderPrint({
      row_count <- input$ProductDataTable_rows_selected
      data <- Product()[row_count, ] 
      cat('Row Selected: ')
      cat(data[,1]) #display the selected row 1st col value  


    })

  })
}

shinyApp(ui, server)