R DT 数据表 - 格式化文本字段并垂直对齐另一个字段

Question

I have a dataset with a text field which I would like to display using the function datatable from the package DT . I would also like to (1) format that text field so that the line breaks are displayed and emphasis is placed on certain chunks of text; and (2) vertically align the remaining fields so that their values are pushed to the top.

Consider the below example:

library(DT)
L <- 10
datatable(
  data.frame(
    var1 = sapply(1:L, function(x) 
      paste("<X>",paste0(x,
                         letters, 
                         LETTERS, 
                         "\n", 
                         collapse=" "))),
    var2 = round(rnorm(L),2)
  ) 
)

As you can see, the output ignores \\n . I would also like to make <X> bold. I've tried using HTML tags such as <br> but nothing seems to work as the text inside var1 is escaped. Unescaping it (which can be achieved via datatable options) is not a good idea as the (actual) text contains special characters. I would also like the values of var2 to be pushed to the top.

Just in case it make a difference, I would like to use the outputs in a Shiny web-app.

Does anyone have any suggestions on how to achieve what I'm looking for?

Many thanks in advance.

Answer 1

To implement the line break in the DT cells you need to use <br/> instead of \\n and escape(it will be read as HTML) the column with the escape argument.

To change the alignment of a value in a cell you can use the columnDefs argument within the options of datatable function. The problem is that you only can align horizontal.( left, right and center) With the rowCallback function I can manually set every value in the second column to top alignment. But this is not an ideal solution.

library(DT)
L <- 10

dataset <- data.frame(
  var1 = sapply(1:L, function(x) 
    paste("<X>",paste0(x,
                       letters, 
                       LETTERS, 
                       "<br/>", 
                       collapse=" "))),
  var2 = round(rnorm(L),2)
)

datatable(dataset, escape = 1,  
  options = list(
    columnDefs = list(list(className = 'dt-center', targets = 2)),
    rowCallback=JS(paste0("function(row, dataset) {var value=dataset[2]; if (value!==null) $(this.api().cell(row,2).node()).css({'vertical-align': 'text-top'});}"))
  )
)

Answer 2

To vertically align your column content you can do this:

T1 <- datatable(dataset)

 T1 %>%
  formatStyle(c('column_1','column_2'), 'vertical-align'='top') %>% 
  formatStyle(c('column_1','column_2'), 'text-align' = 'left')