Shiny App 动态上传和下载数据不起作用

问题描述

我是 Shiny Apps 的新手，所以非常感谢您的帮助！我的代码目前已损坏，我不确定原因。

这是我的问题：

1. 如何使此代码起作用？我希望用户上传一个 csv 文件，在数据表中查看它，然后下载数据表
2. 如何使用列中的正则表达式过滤行？我希望应用此正则表达式 df[with(df,grepl("\\bDATE\\b|\\b[0-9]{4}-[0-9]{2}-[0-9]{2}\\b|\\b[0-9]{2}-[0-9]{2}\\b|[0-9]{4}\\b",close_notes)),]。您可以假设每个 csv 文件都将该列作为数据的一部分（在示例中为 close_notes）。

谢谢！我的代码如下。

library(shiny)

ui <- fluidPage(
    sidebarLayout(
        sidebarPanel(
            fileInput("file1","Choose CSV File",accept = c(
                          "text/csv","text/comma-separated-values,text/plain",".csv")
            ),tags$hr(),checkBoxInput("header","Header",TRUE),# Button
            downloadButton("downloadData","Download")
            
        ),mainPanel(
            dataTableOutput("contents")
        )
    )
)




server <- function(input,output) {

    output$contents <- renderDataTable({
        # input$file1 will be NULL initially. After the user selects
        # and uploads a file,it will be a data frame with 'name',# 'size','type',and 'datapath' columns. The 'datapath'
        # column will contain the local filenames where the data can
        # be found.
        inFile <- input$file1
        
        if (is.null(inFile))
            return(NULL)
        
        read.csv(inFile$datapath,header = input$header)
    })
    
    output$downloadData <- downloadHandler(
        filename = function() {
            paste(input$dataset,".csv",sep = "")
        },content = function(file) {
            write.csv(datasetinput(),file,row.names = FALSE)
        }
    )
}

shinyApp(ui,server)

解决方法

试试这个

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      fileInput("file1","Choose CSV File",accept = c(
                  "text/csv","text/comma-separated-values,text/plain",".csv")
      ),tags$hr(),checkboxInput("header","Header",TRUE),# Button
      downloadButton("downloadData","Download")
      
    ),mainPanel(
      dataTableOutput("contents")
    )
  )
)

server <- function(input,output) {
  
  datasetInput <- reactive({
    req(input$file1)
    # input$file1 will be NULL initially. After the user selects
    # and uploads a file,it will be a data frame with 'name',# 'size','type',and 'datapath' columns. The 'datapath'
    # column will contain the local filenames where the data can
    # be found.
    inFile <- input$file1
    
    if (is.null(inFile))
      return(NULL)
    
    read.csv(inFile$datapath,header = input$header)
  })
  
  output$contents <- renderDataTable({
    datasetInput()
  })
  
  output$downloadData <- downloadHandler(
    filename = function() {
      paste("myfile",Sys.Date(),".csv",sep = "")
    },content = function(file) {
      write.csv(datasetInput(),file,row.names = FALSE)
    }
  )
}

shinyApp(ui,server)