在R Shiny

Question

我正在尝试显示一个列数为'n'的数据表，如下所示

Begin Date | EndDate | Month | Year | Count of Students
2/1/2014 | 1/31/2015 | Jan | 2014 | 10
3/1/2014 | 2/28/2015 | Feb | 2014 | 20
4/1/2014 | 3/31/2015 | Mar | 2014 | 30
5/1/2014 | 4/30/2015 | Apr | 2014 | 40

我希望通过启用向下钻取/钻取功能使此数据表具有交互性，用户可以单击“学生计数”字段中的每个值来查看这些数字背后的基础原始数据10， 20,30和40。 例如，如果用户点击“10”，他/她应该能够看到该计数背后的学生原始数据。这类似于excel中的Pivot表概念，用户可以在其中查看Pivot表背后的基础数据。有没有办法用R Shiny做同样的事情？

Answer 1

是的，使用DT包捕获选定的行并对主集进行子集化。以下是使用iris集合的示例：

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

# create a summary table
summary_iris <- group_by(iris, Species) %>%
  summarise(Count = n())

ui <- fluidPage(
  dataTableOutput("summary")
  , dataTableOutput("drilldown")
)


server <- function(input, output){

  # display the data that is available to be drilled down
  output$summary <- DT::renderDataTable(summary_iris)

  # subset the records to the row that was clicked
  drilldata <- reactive({
    shiny::validate(
      need(length(input$summary_rows_selected) > 0, "Select rows to drill down!")
    )    

    # subset the summary table and extract the column to subset on
    # if you have more than one column, consider a merge instead
    # NOTE: the selected row indices will be character type so they
    #   must be converted to numeric or integer before subsetting
    selected_species <- summary_iris[as.integer(input$summary_rows_selected), ]$Species
    iris[iris$Species %in% selected_species, ]
  })

  # display the subsetted data
  output$drilldown <- DT::renderDataTable(drilldata())
}

shinyApp(ui, server)