如何从已过滤数据表（DT）的选定行中获取数据？ [英] How do I get the data from the selected rows of a filtered datatable (DT)?

问题描述

DT包允许您使用 input $ tableID_rows_selected 获取选定行的索引。这对于没有过滤数据的表非常有用。但是，如果我们有一个经过过滤的数据集，由于行索引已关闭，我们不能使用相同的方法。

The DT package allows you to get the indices of selected rows using input$tableID_rows_selected. This works great for tables that do not have filtered data. However, if we have a filtered dataset, we can't use this same approach, as the row indices are off.

对于经过过滤的数据集，我们将如何处理？

For a filtered dataset, then, how would we get the data in the selected rows of a datatable?

下面，我发布了一个基本的闪亮应用程序，其中显示了四个表：第一个是原始mtcars数据集，第二个获取第一个中的选定行。第三和第四做相同的事情，但是在过滤器 sliderInput上过滤了数据集之后。

Below, I've posted a basic shiny app that shows four tables: the first one is the original mtcars dataset and the second gets the selected rows in the first. The third and the fourth do the same thing, but after filtering the dataset on the "filter" sliderInput.

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

ui <- fluidPage(
  DT::dataTableOutput("origTable"),
  DT::dataTableOutput("origTableSelected"),
  sliderInput("filter", label = "Filter by cyl", min = 4, max = 8, step = 2, value = 6),
  DT::dataTableOutput("filteredTable"),
  DT::dataTableOutput("filteredTableSelected")
)


server <- function(input, output, session) {

  output$origTable <- DT::renderDataTable({
    datatable(
      mtcars,
      selection = list(mode = "multiple"),
      caption = "Original Data"
    )
  })

  origTable_selected <- reactive({
    ids <- input$origTable_rows_selected
    mtcars[ids,]
  })

  output$origTableSelected <- DT::renderDataTable({
    datatable(
      origTable_selected(),
      selection = list(mode = "multiple"),
      caption = "Selected Rows from Original Data Table"
    )
  })

  output$filteredTable <- DT::renderDataTable({
    datatable(
      filter(mtcars, cyl == input$filter),
      selection = list(mode = "multiple"),
      caption = "Filtered Table (based on cyl)"
    )
  })

  filteredTable_selected <- reactive({
    ids <- input$filteredTable_rows_selected
    mtcars[ids,]
  })

  output$filteredTableSelected <- DT::renderDataTable({
    datatable(
      filteredTable_selected(),
      selection = list(mode = "none"),
      caption = "Table that gets data from unfiltered original data"
    )
  })
}

shinyApp(ui = ui, server = server)

推荐答案

一种方法：在filteredTable_selected（）函数中，在其中创建数据ta，您将放入第四个DT，像在第三张表中那样使用 filter（mtcars，cyl == input $ filter），而不是 mtcars 。这样，行索引将匹配。

One way: in your filteredTable_selected() function, where you're creating the data you'll put in your fourth DT, use filter(mtcars, cyl == input$filter) like you did for your third table instead of mtcars. This way, the row indices will match.

如果您担心较大的数据集上的性能问题，只需过滤反应表达式中的数据即可缓存其输出。这样，您过滤的内容不会超过输入$的过滤值更改。

If you're worried about performance issues on larger datsets, just filter the data in a reactive expression, which caches its output. This way, you won't filter more than your input$filter value changes.

server <- function(input, output, session) {
  filteredTable_data <- reactive({
    filter(mtcars, cyl == input$filter)
  })

  output$filteredTable <- DT::renderDataTable({
    datatable(
      filteredTable_data(),
      selection = list(mode = "multiple"),
      caption = "Filtered Table (based on cyl)"
    )
  })

  filteredTable_selected <- reactive({
    ids <- input$filteredTable_rows_selected
    filteredTable_data()[ids,]
  })

  output$filteredTableSelected <- DT::renderDataTable({
    datatable(
      filteredTable_selected(),
      selection = list(mode = "none"),
      caption = "Table that gets data from unfiltered original data"
    )
  })
}

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