How do you get dates to show up in a date format when working with a Shiny Table?

Question

I'm stuck trying to get dates to show up in a Shiny table. I have done some research and see that in the past xtable does not work nicely with Shiny. There are a couple of questions on SO that dealt with this issue. The one routinely reference can be found here R: xtable and dates.

My problem is that 1)I'm extremely new at programming in Shiny and using xtable. 2) I am unfamiliar with using POSIXct. 3) I don't understand the solution provided in the link above.

Please provide a helping hand for the basic code below. The idea is that somebody would use this app to enter data daily. These data would be stored on a .csv. When stored on the .csv only the numeric value of the R date is stored. This is what shows up on the Shiny table as well. Please teach me how to format correctly in both the table and the .csv file.

Before examining the code below, know that there would be a .csv file stored that would have the Headers Date, A, B. Let's call this file "log" and it would be stored locally. Here is the code:

library(shiny)

log <- read.table("V:\\My\\Path\\log.csv",sep=",",header=T)

ui <- fluidPage(

  sidebarLayout(

    sidebarPanel(width=2,

                 #Enter Date
                 dateInput("date","Date",min="2016-07-04", max = "2017-07-04"),

                 #Enter Combo
                 selectInput(inputId = "a", "A", c("Choose one" = "","A1", "A2", "A3"), multiple = FALSE, selectize = TRUE, width = NULL, size = NULL),

                 #Enter Number
                 numericInput(inputId = "b", "Favorite Number", NULL, min = 0, max = NA),

                 #Enter Submit to write info to file
                 actionButton(inputId = "submit", "Submit", icon = NULL, width = NULL)

                 ), 

    mainPanel(
      # Application title
      titlePanel("Read Date"),
      tableOutput("summary"))
  )
)


server <- function(input, output) {
  #Create vector of current trial results
  data <- eventReactive(input$submit, {         
    cbind(input$date,input$a, input$b) 

  })

  #Append current trial results to master list
  observeEvent(input$submit, {
    write.table(data(), file="V:\\My\\Path\\log.csv", sep=",", col.names= FALSE, row.names=F, append = T)

  })

  #Create datatable variable reading in latest log  

  datatable <- eventReactive(c(input$agent,input$submit), {          #Putting both reactive variables allow to see dataset without running and see updated dataset after running.
    data.frame(read.table("V:\\My\\Path\\log.csv",sep=",",header=T))

  })

  #Create Table  

  output$summary <- renderTable({

    datatable() }, digits=2,align = "cccc" )

}

shinyApp(ui = ui, server = server)

It seems the answer is to write as character to the log file and read it back in as a character. I can't figure out to do this. Am I on the right track? Because I'm learning I'll take any other suggestions on how to improve my code.

Answer 1

I finally figured out the simple solution.

I just changed the code when I build the dataframe from

  data <- eventReactive(input$submit, {         
cbind(input$date,input$a, input$b) 

to

  data <- eventReactive(input$submit, {         
cbind(as.character(input$date),input$a, input$b))

Adding the as.character() seems to have done the trick. I don't know if this will have consequences later, but the displayed table now looks nice.