DT 数据表中的动态列对齐

Question

我有一个更大的数据表输出，其中包含不同数量的列，这是我在小部件中选择的。我想动态右对齐我的列，但只有在列数固定时才找到解决方案。我希望我可以调整 target= 命令中的引用以使其动态化。不知何故，这不起作用，当列数小于默认引用时，我没有得到输出。我在某处读到反应式语句不适用于数据表选项。我附上了 MWE。

rm(list=ls()) 
library(shiny)
library(datasets)
library(datatable)
DT<-data.table(matrix(abs(rnorm(100,sd=100000)),nrow=10))


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

  # Return the requested dataset
  columns <- reactive({
    switch(input$columns,
        all= c("V1","V2","V3","V4","V5","V6","V7","V8","V9","V10"),
        left= c("V1","V2","V3","V4","V5"),
        right= c("V6","V7","V8","V9","V10"))
           })


  # Show table
  output$view <- DT::renderDataTable(
    format(DT[,.SD,.SDcols=columns()],digits = 0,scientific=F),
      option=list(columnDefs=list(list(targets=0:(length(columns())-1), class="dt-right")))
  )
}) 
  library(shiny)

# Define UI for dataset viewer application
ui<-shinyUI(fluidPage(

  # Application title
  titlePanel("Shiny Text"),

  # Sidebar with controls to select a dataset and specify the
  # number of observations to view
  sidebarLayout(
    sidebarPanel(
     selectInput("columns", label = h3("Select Columns"),
                    choices = list("All columns" = "all", "Left side" = "left",
                                    "Right side" = "right"), selected = "all")
    ),

    # Show a summary of the dataset and an HTML table with the 
     # requested number of observations
    mainPanel(
      DT::dataTableOutput("view")
    )
  )
))



runApp(list(ui=ui,server=server))

Answer 1

从某种意义上说，数据表选项不是反应式的，您无法在不重绘整个表格的情况下更改选项，但如果您愿意重绘表格，那么这不是问题，请参见下文：

如果您将服务器功能更改为此它应该可以工作：

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

  # Return the requested dataset
  columns <- reactive({
    switch(input$columns,
           all= c("V1","V2","V3","V4","V5","V6","V7","V8","V9","V10"),
           left= c("V1","V2","V3","V4","V5"),
           right= c("V6","V7","V8","V9","V10"))
  })

  # reactive datatable

  rdt <- reactive({
    DT::datatable(format(DT[,.SD,.SDcols=columns()],digits=0,scientific=FALSE),
                  option=list(columnDefs=list(
                    list(targets=seq_len(length(columns()))-1, 
                         class="dt-right"))))
  })


  # Show table
  output$view <- DT::renderDataTable(
    rdt()
    )

}) 

我正在创建一个响应式datatable，它响应columns() 并使用正确的columnDef 重新绘制表格。如果你有很多数据，这会很慢。