Change number format in renderDataTable - r

Question

How do I define number format for datatable in Shiny? I would like to display 2 decimal digits only for some columns, but do not understand where it should be defined in my application. In server.R or ui.R? In server.R, this what I have in renderDataTable:
output$woeTable <- renderDataTable({
input$tryTree
input$threshold
# The following returns data frame with numeric columns
get(input$dfDescr)[['variables']][[input$columns]][['woe']]
},
options=list(
paging = FALSE,
searching = FALSE)
)
How do I format 2nd and 3rd column to display only two decimal digits?

Answer 1

just use round command:
output$woeTable <- renderDataTable({
input$tryTree
input$threshold
# The following returns data frame with numeric columns
A = get(input$dfDescr)[['variables']][[input$columns]][['woe']]
A[,2] = round(x = A[,2],digits = 2)
A[,3] = round(x = A[,3],digits = 2)
A
},
options=list(
paging = FALSE,
searching = FALSE)
)
you can also use fnRowCallback option in renderDataTable function if you insist to keep data with more digit and just change representation in output:
output$woeTable <- renderDataTable({
input$tryTree
input$threshold
# The following returns data frame with numeric columns
get(input$dfDescr)[['variables']][[input$columns]][['woe']]
},
options=list(
paging = FALSE,
searching = FALSE,
fnRowCallback = I("function( nRow, aData, iDisplayIndex, iDisplayIndexFull ) {ind = 2; $('td:eq('+ind+')', nRow).html( (aData[ind]).toFixed(2) );}"))
)
update for DT 1.1:
you should change
fnRowCallback = I("function( nRow, aData, iDisplayIndex, iDisplayIndexFull ) {ind = 2; $('td:eq('+ind+')', nRow).html( (aData[ind]).toFixed(2) );}"))
to
rowCallback = I("function( nRow, aData) {ind = 2; $('td:eq('+ind+')', nRow).html( parseFloat(aData[ind]).toFixed(2) );}"))