Sorting Column DataTable for Shiny App by abs-CodePudding

Was hoping someone can help sort a column by absolute value in a Shiny app in the datatable() function? Tried multiple methods (dplyr, arrange, etc) but for some reason it's not clicking with me. It's a three column datatable, trying to sort column 2/val2 by the absolute value.

  table_stage <- reactive ({
    tbl <- datatable(tabledat(),
                     rownames = FALSE,
                     options = list(
                       columnDefs = list(list(className = "dt-center", targets = 2)),
                       order = list(list(2, "asc"))
                     )) %>%
      formatRound("val", 2) %>%
      formatRound("val2", 2)
    
    return(tbl)
  })

This is definitely wrong, did not work at all.

  table_stage <- reactive ({
    tbl <- datatable(tabledat(),
                     rownames = FALSE,
                     options = list(
                       columnDefs = list(list(className = "dt-center", targets = 2)),
                       order = list(list((arrange(abs(2)), "desc"))
                     )) %>%
      formatRound("val", 2) %>%
      formatRound("val2", 2)
    
    return(tbl)
  })

CodePudding user response：

The code runs without problems when using dataTableOutput in a UI context and renderDataTable in the Server function.

This script works with order by mpg (the first column in the example table) and if mtcars is a data frame, it works too.

library(data.table)
library(shiny)
library(dplyr)
library(DT)

if (interactive()) {
  
  ui <- fluidPage(
    dataTableOutput("table")
  )
  
  #optional test data
  tabledat <- data.table::as.data.table(mtcars)
    
  server <- function(input, output) {
    output$table <- 
      renderDataTable({
        tabledat %>% 
          datatable(
            rownames = FALSE,
            options = list(
              columnDefs = list(list(className = "dt-center", targets = 2)),
              order = list(list(1, "asc"))
            )
          )
      },
      )
    
  }
  shinyApp(ui, server)
}

CodePudding user response：

You need to use the render option:

library(DT)

js <- "
function(data, type, row, meta) {
  if(type === 'sort') {
    data = Math.abs(data);
  }
  return data;
}
"

mydata <- as.data.frame(
  matrix(runif(40, -10000, 10000), nrow = 10, ncol = 4)
)

datatable(
  mydata,
  options = list(
    "columnDefs" = list(
      list(
        "targets" = 1,
        "render"  = JS(js)
      )
    )
  )
)