Adding Vectors as paramters in R

[vinayprakash808]

Hi all,

Is there a way to declare vectors as parameters in R. Example, I have a function(finat_DT(data)) that returns DTtable. So here data parameter is datasets. But can we pass another arguement like finat_DT(data, column_hidden = a) so that we can declare ````a````` as below

columnDefs = list(list(visible=FALSE, targets=a)) 

So when we call finat_DT(data, column_hidden = c(1,2)) #only first 2 columns gets hidden.
similarly finat_DT(data, column_hidden = c(1,2,6))# only 1, 2 and 6 columns gets hidden

Is this possible to achieve?

Below is the sample example

library(shiny)
library(DT)

ui <- fluidPage(
  dataTableOutput("tabout")
)

server <- function(input, output, session) {
  small_fun <- function(data,c = a){
    return(DT::datatable(data,options = list(columnDefs = list(list(visible=FALSE, targets=a)))))
  }
  
  output$tabout <- renderDataTable({
    small_fun(iris,c = 3)
  })
}

shinyApp(ui, server)

[FJCC]

Inside of small_fun, the index of the columns you want to have hidden is stored in c, so you need to set targets = c.

 small_fun <- function(data,c = a){
    return(DT::datatable(data,options = list(columnDefs = list(list(visible=FALSE, targets=c)))))
  }

In fact, a is not defined anywhere, so setting c=a as the default for the function does not do anything helpful.

[vinayprakash808]

Great. But can we keep parameter c optional. Example if I need not format any columns. Can we do below

function(data)   ## so that no format happens

[FJCC]

You can pass NULL to c if you want all of the columns to be shown.

server <- function(input, output, session) {
  small_fun <- function(data,c = NULL){
    return(DT::datatable(data,options = list(columnDefs = list(list(visible=FALSE, targets=c)))))
  }
  
  output$tabout <- renderDataTable({
    small_fun(iris)
  })
}

[vinayprakash808]

Great thanks, But i just tried differently. When i try below, it wont work (Getting error)

  small_fun <- function(data,c = NULL){
    return(DT::datatable(data) %>% formatCurrency(columns = c, currency = "", interval = 3, mark = ",",digits = 2))
  }
Error : zero-length inputs cannot be mixed with those of non-zero length

[FJCC]

I suggest you use something like

small_fun <- function(data,c = NULL){
  if (is.null(c)) {
    return(DT::datatable(data)
  } else {
    return(DT::datatable(data) %>% formatCurrency(columns = c, currency = "", interval = 3, mark = ",",digits = 2))
  }
}

[vinayprakash808]

Thanks. It is working