删除r有光泽的特定行

Question

I am currently programming a shiny app in which the user can add and delete lines to a data frame.

To do so, I first initialize the data frame inside the shinyServer function using:

values <- reactiveValues()
values$df <- data.frame(v1 = NA,
                      v2 = NA,
                      v3 = NA,
                      v4 = NA,
                      v5 = NA,
                      v6 = NA,
                      v7 = NA,
                      v8 = NA
                      )

Next, I have a button and the corresponding code to add lines to the reactiveValue :

newEntry <- observe({
 if(input$add.button > 0) {

 new.value <- isolate(input$v1 * input$v2 * input$v3 * input$v4)

 newRow <- isolate(c(input$v1, input$v2, input$v3, input$v4, 
                      input$v5, input$v6, input$v7, new.value))

 isolate(values$df <- rbind(values$df, newRow))
}

})

So far, this code works perfect for me. Finally, I want to allow the user to remove the last row, or specific rows from the data frame. To do so, I have a delete button ( input$delete.button ) and a numericInput() to select the row. The logic I wanted to implement should be: if no specific row is selected, delete the last row, else delete the selected row. The code I tried so for is:

deleteEntry <- observe({
 if(input$delete.button > 0) {


  if(is.na(input$row.selection)){

    values$df <- isolate(values$df[-nrow(values$df), ])

  } else {

    what does here?

  }
}

})

So the first statement, deleting the last row works, but deleting a specific row always fails. I tried different attempts including eventReactive() but nothing works so far.

Edit: This is the relevant part of my ui.r:

# Add button
actionButton(inputId = "add.button", label = "Add", icon = icon("plus")), 

# Delete button 
actionButton(inputId = "delete.button", label = "Delete", icon = icon("minus")),

# Row selection
numericInput(inputId = "row.selection", label = "Select row to be deleted", min = 1, max = 100, value = ""),

Any ideas to to implement this logic? Best, Fabian

Answer 1

Just delete the specific element using

values$df <- isolate(values$df[-input$row.selection, ])

using some parts of your code I created this simple working example to show how to delete the spesific row.

runApp(list(
  ui = shinyUI(
        fluidPage(
            sidebarLayout(
                sidebarPanel(
                    # Add button
                    actionButton(inputId = "add.button", label = "Add", icon = icon("plus")), 
                    # Delete button 
                    actionButton(inputId = "delete.button", label = "Delete", icon = icon("minus")),
                    # Row selection
                    numericInput(inputId = "row.selection", label = "Select row to be deleted", min = 1, max = 100, value = "")
                ),
                mainPanel(
                    verbatimTextOutput('text')
                )
            )
        )
  ),

    server = function(input, output, session) {
        values <- reactiveValues()
                values$df <- data.frame(v1 = NA,
                      v2 = NA,
                      v3 = NA,
                      v4 = NA,
                      v5 = NA,
                      v6 = NA,
                      v7 = NA,
                      v8 = NA
                      )

        newEntry <- observe({
            cat("newEntry\n")
            if(input$add.button > 0) {
                new.value <- isolate(input$v1 * input$v2 * input$v3 * input$v4)
                newRow <- isolate(c(input$v1, input$v2, input$v3, input$v4, 
                                                        input$v5, input$v6, input$v7, new.value))
                isolate(values$df <- rbind(values$df,sample(1:8)))
            }
        })

        deleteEntry <- observe({
            cat("deleteEntry\n")
            if(input$delete.button > 0) {
                if(is.na(isolate(input$row.selection))){
                    values$df <- isolate(values$df[-nrow(values$df), ])
                } else {
                    values$df <- isolate(values$df[-input$row.selection, ])
                }
            }

        })

        output$text = renderPrint({
                values$df 

        })

    }
)

If this is not what you want, please modify the code and edit your questions.

As an advice for future questions, please try always to provide a working minimal example that shows the problem or the desired feature. It will always simplifies the understanding of the problem and also provide a simple way to test if the solution works as you expected.

Regards