R闪亮的observeEvent问题 [英] R Shiny observeEvent issues

问题描述

当试图在数据表中选择行并且有人按下删除行"开关时，我正在尝试从数据框中删除行. input $ click_rows_selected提供所选行的ID.

I am trying to delete the rows from a dataframe when they have been selected in the datatable and someone presses the "Delete Rows" switch. input$click_rows_selected gives the id's of the selected rows.

我对observeEvent和observe的使用似乎有问题，因为代码是在我第一次轻按开关时删除选定的行.但是，此后每次我选择一行时，它也会删除该行.开关关闭后，如何停止删除该行? if和else语句似乎根本没有帮助.

There seems to be something wrong with my use of observeEvent and observe, because the code deletes the selected rows the first time I flick the switch. Afterwards however, every time I select a row it also deletes that row. How do I get to stop deleting the row once the switch has been turned off? The if and else statement don't seem to help at all.

代码的简化版:

observeEvent(input$deleterows,{

  if(input$deleterows==TRUE){

  observe({
        if (is.null(input$click_rows_selected))
           return()
        values$df <- values[input$click_rows_selected,]})} else{ 
 print("check")}
 })

推荐答案

以下代码应帮助您寻求解决方案. 请注意，通常应避免嵌套observe的做法.

The following code should help you toward a solution. Please note that the practice to have nested observe should be in general avoided.

我添加了updateCheckboxGroupInput，因为我认为在示例上下文中这是合理的.

I've added updateCheckboxGroupInput as I thought it made sense in the context of the example.

library(shiny)

values <- reactiveValues(df = iris)

ui <- fluidPage( 

  sidebarLayout(

    sidebarPanel(
      checkboxGroupInput('inputId', label=NULL, choices = colnames(df), selected = NULL,
           inline = FALSE, width = NULL, choiceNames = NULL, choiceValues = NULL),
      actionButton("deleterows", "push to delete") 
    ),

    mainPanel(tableOutput("contents")
    )
  ))

server <- function(input,output,session){

  observeEvent(input$deleterows,{
    cols <- setdiff(colnames(values$df), input$inputId)
                    values$df <- values$df[c(cols)]

                    updateCheckboxGroupInput(session, 'inputId', label = NULL, choices = colnames(values$df),
                      selected = NULL, inline = FALSE, choiceNames = NULL,
                      choiceValues = NULL)
 })

output$contents <- renderTable({
        values$df 
  })

}

shinyApp(ui,server)

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