Shiny app reading input as character

[calvarez]

Hello everybody. I'm having trouble with my shiny app and I have been stuck in this for several hours.

My app is supposed to take a data frame and display a table of the data frame, and a plot of some of the information contained in the data frame. The plot is created through a function I designed which receives as input the data frame. Which data frame that is going to be ploted or printed is selected by the user with a selectInput. The select input looks like this:

selectInput(inputId = "bank", label= "Choose the bank to analyse", 
                                 choices = c("Bank One" = "bank1",
                                                         "Bank Two" = "bank2",
                                                         "Bank Three" = "bank3"),
                                  selected = "bank1"),            

I have many banks and for each bank I generate a data frame named bank1, bank2 and so on. The data frames are created after some burdensome calculations I put in the server function. I'm creating a data frame named data as a reactive like this:

  data <- reactive({ input$bank})

And then it is supposed to display the data frame with the following code chunk:

  output$table1 <- DT::renderDataTable({
    DT::datatable(data(), options = list(pageLength=6)))
  })

The code as shown generates the following Error message: 'data' must be 2-dimensional (e.g. data frame or matrix).

The app is actually generating the data frames becouse if, for example, I replace the input$bank with bank1 the data frame is displayed correctly. So, the data frames not existing is not the problem.

The problem, I believe, is that somehow shiny is reading the input as character and not as a data frame, even though the data frame exists. But so far I do not know why this is happening and how to solve it. I'd really appreciate your help.

I do not provide the whole app becouse it is too large.

[nirgrahamuk]

data <- reactive({ get(req(input$bank))})

[woodward]

@calvarez

input$bank

Shiny inputs are usually undefined (NULL) when the app starts so you need to check that the input exists before you use it, as suggested by @nirgrahamuk, using req().

[tjpalanca]

I think what is happening is that the input$bank is not the data frame you were expecting:

• Is it filled in by a text field (and therefore contains a string ”bank1” and not the actual data frame)? In this case you can use get() to fetch the binding attached to that name or you can use a switch() statement to map from the string to the data frame.
• Maybe it is actually a file that was uploaded (although that seems less likely from your description. In this case you’ll need to read it from disk first before plugging it in.

[calvarez]

Thanks nirgrahamuk!! It works!!

[calvarez]

Thanks for your help tjpalanca. As you mentioned, my app was fixed with the get() command.