1

I'm building an app that allows user to pass the value from selectizeInput or checkboxInput to form a dataframe. I've searched a while and found these sources that similar to what I expect:

  1. handsontable

It is from here: https://github.com/jrowen/rhandsontable. Mine is quite similar to this exampe: 

shiny::runGitHub("jrowen/rhandsontable",
                 subdir = "inst/examples/rhandsontable_portfolio")

But I want to use shiny widgets to pass values to the dataframe. It should be able to add/remove rows as following example:

  1. shinyIncubator

code here:

library("shiny")
library('devtools')
install_github('shiny-incubator', 'rstudio')
library("shinyIncubator")

# initialize data with colnames
df <- data.frame(matrix(c("0","0"), 1, 2))
colnames(df) <- c("Input1", "Input2")
    server = shinyServer(
      function(input, output) {
        # table of outputs
        output$table.output <- renderTable(
          { res <- matrix(apply(input$data,1,prod))
          res <- do.call(cbind, list(input$data, res))
          colnames(res) <- c("Input 1","Input 2","Product")
          res
          }
          , include.rownames = FALSE
          , include.colnames = TRUE
          , align = "cccc"
          , digits = 2
          , sanitize.text.function = function(x) x      
        )  
      }
    )

ui = shinyUI(
  pageWithSidebar(

    headerPanel('Simple matrixInput example')

,
sidebarPanel(

  # customize display settings    
  tags$head(
    tags$style(type='text/css'
               , "table.data { width: 300px; }"
               , ".well {width: 80%; background-color: NULL; border: 0px solid rgb(255, 255, 255); box-shadow: 0px 0px 0px rgb(255, 255, 255) inset;}"
               , ".tableinput .hide {display: table-header-group; color: black; align-items: center; text-align: center; align-self: center;}"
               , ".tableinput-container {width: 100%; text-align: center;}"
               , ".tableinput-buttons {margin: 10px;}"
               , ".data {background-color: rgb(255,255,255);}"
               , ".table th, .table td {text-align: center;}"

    )
  )
  ,
  wellPanel(
    h4("Input Table")
    ,      
    matrixInput(inputId = 'data', label = 'Add/Remove Rows', data = df)
    , 
    helpText("This table accepts user input into each cell. The number of rows may be controlled by pressing the +/- buttons.")
  )
)
,
mainPanel(
  wellPanel(
    wellPanel(
      h4("Output Table")
      ,
      tableOutput(outputId = 'table.output')
      ,
      helpText("This table displays the input matrix together with the product of the rows of the input matrix")
    )
  )
    )
  )
)
runApp(list(ui = ui, server = server))

The value should be entered by user from shiny widgets such as selectizeInput, checkboxInput or textInput and passed to the dataframe once the user click my actionButton. What I want is pretty similar to the combination of the above functions but I don't know how to do. Any suggestions?

Many thanks in advance.

Eric Hung
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  • The simplest way is to directly use `rhandsontable` (you can edit, add and remove rows). Building it yourself is possible as your described using a combination of textInput and actionButton (in the server code, use `observeEvent` to observe click on the button, and then get values from the textInput and build your data frame) – Xiongbing Jin Mar 31 '16 at 20:46
  • I can pass value through shiny widgets now but still don't know how to add/remove rows. In addition, I need to fix the previous row after I add a new one. That is, if I press `submit` I will have my first row with default values which may be changed with the value of `selectizeInput` or `textInput` because now I only have one row. Then, after I `submit` a new row with new values, the value of the first row should be fixed, i.e., not gonna be changed with input because the second row will. – Eric Hung Apr 01 '16 at 00:46
  • You need to have three different buttons: "insert", "update", and "delete". For the latter two, you also need an additional input to specify which row to update or delete. – Xiongbing Jin Apr 01 '16 at 02:11
  • @warmoverflow thanks. I think I find the solution:) – Eric Hung Apr 01 '16 at 02:17

1 Answers1

6

Though I ended up using none of the two packages, this worked fine:

library(shiny)

server = shinyServer(function(input, output, session){

  values <- reactiveValues()

values$DT <- data.frame(Name = NA,
                        status = NA,
                        compare = NA,
                        stringsAsFactors = FALSE)

newEntry <- observeEvent(input$addrow, {
    newLine <- c(input$textIn, input$boxIn, input$selectIn)
    values$DT <- rbind(values$DT, newLine)
})

newEntry <- observeEvent(input$revrow, {
  deleteLine <- values$DT[-nrow(values$DT), ]
  values$DT <- deleteLine
})

  output$table <- renderTable({
    values$DT
  })

})

ui = shinyUI(navbarPage(
  "Backtest System", inverse = TRUE, id = "navbar",
  tabPanel("Strategy",
           sidebarLayout(
             sidebarPanel(
               h4("Indicator"),
               textInput("textIn", "Text", "try"),
               checkboxInput("boxIn", "Box", TRUE),
               selectizeInput("selectIn", "Select", 
                              choices = c(">" = ">",
                                          ">=" = ">=",
                                          "<" = "<",
                                          "<=" = "<=")),
               actionButton("addrow", "Add Row"),
               actionButton("revrow", "Remove Row")
             ),
             mainPanel(
               tableOutput("table")
             )
           )
  )
  )
)
runApp(list(ui = ui, server = server))
Eric Hung
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