在第n个变量上指定列宽，其中n是取决于输入选择器的变量

Question

我有一个带有DT数据表的应用。该表按用户输入的某些指定尺寸分组。用户指定1,2,3或4个分组变量时，我希望这些变量的宽度为100px。

要复制的完整代码如下。有问题的特定代码块是：

   output$eg_table <- DT::renderDT({my_flights_react() }, 
                                   filter = 'top', options = list(dom = 'tip',
                                                                  autoWidth = T,
                                                                  scrollX=T,
                                                                  columnDefs = list(list(width = '100px',
                                                                                         targets = 1:length(input$group_dims)))
                                                                  )
                                   )

如果我将1:length(input$group_dims)改为1:3，那么前三列确实会调整为指定的长度。似乎DT或Shiny无法正确读取输入input $ group_dims的长度。

如何调整前n个列宽，其中列数是取决于用户输入的变量？

要复制的完整代码，请注意，即使我在选择器中选择了所有字段，也只有第一列显示为100px：

library(tidyverse)
library(shiny)
library(nycflights13)
library(lubridate)

# Define UI for application that draws a histogram
ui <- fluidPage(

   # Application title
   titlePanel("Example Shiny App"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
        selectInput(inputId = "group_dims", 
                    label =  "group_dims", 
                    choices = c("carrier", "origin", "dest", "tailnum"),
                    selected = c("carrier"),
                    multiple = T) # There can be only one
      ),

      # DT table
      mainPanel(
         DT::dataTableOutput("eg_table")
      )
   )
)

# Define server logic required to draw a histogram
server <- function(input, output) {

  # initial preprocessing
  my_flights <- flights %>% 
    filter(month == 11 & day >= 14) %>% # just data for 2 weeks
    mutate(date = ymd(paste(year, month, day, sep = "-"))) %>% 
    select(date, carrier, origin, dest, tailnum, distance) %>% 
    mutate(date = ordered(format(date, "%d-%b"), levels = format(sort(unique(date)), "%d-%b")))


  # recative preprocessing
  my_flights_react <- reactive({
    dims <- input$group_dims
    my_flights %>%
      group_by_at(vars(date, dims)) %>%
      summarise(distance = sum(distance)) %>%
      pivot_wider(names_from = date, values_from = distance) %>%
      replace(is.na(.), 0) %>% 
      ungroup() %>% 
      add_column(Total = rowSums(select(., -dims), na.rm = T), .after = length(dims)) %>% 
      arrange(desc(Total))
  })


   output$eg_table <- DT::renderDT({my_flights_react() }, 
                                   filter = 'top', options = list(dom = 'tip',
                                                                  autoWidth = T,
                                                                  scrollX=T,
                                                                  columnDefs = list(list(width = '100px',
                                                                                         targets = 1:length(input$group_dims)))
                                                                  )
                                   )
}

# Run the application 
shinyApp(ui = ui, server = server)

Answer 1

您的最小示例工作正常。列宽比没有columnsDef位的宽。 （选择后挡板会引发错误，但这并不重要。）