从 Shiny 中上传的文件生成多个图形/绘图

Question

我是 Shiny 的新手（使用 R 工作了几个月），我正在尝试弄清楚处理多个上传文件的“闪亮”方式是什么。

我的目标是有一个用户可以上传多个文件的界面。必须从这些文件中生成大量图表形式的报告。根据我在 Shiny 教程中学到的知识，在服务器端，所有对象都是相互隔离的（这意味着它们无法读取，除非您显式调用另一个函数）。

正如您在下面的代码中看到的，这意味着我必须为每个绘图复制处理代码。这似乎效率低下。处理这个问题的“闪亮”方式是什么？

另外，我遗漏了一些对于示例来说并非绝对必要的代码。本质上，我需要做更多的处理，我不想为每个情节复制所有代码。

我特意询问的是服务器端代码。我想读入包含不同内容的多个文件。服务器端代码中的操作只是占位符，我实际上不想绑定任何东西，但我把它放在那里以保持代码简单。我希望能够对导入的数据框做任何我想做的事情。

library(shiny)

# Define UI for application
ui <- fluidPage(

    # Sidebar with file input
    sidebarLayout(
        sidebarPanel(
            fileInput("people", NULL, multiple = FALSE, accept = ".csv",
                      buttonLabel = "Browse...", placeholder = "people file"),
            fileInput("info", NULL, multiple = FALSE, accept = ".csv",
                      buttonLabel = "Browse...", placeholder = "info file"),
        ),

        # Show the results of the data processing
       mainPanel(
           imageOutput("plot"),
           tableOutput("base_data")
        )
    )
)

# Define server logic required to process the data
server <- function(input, output) {

    output$base_data <- renderTable({
        if(is.null(input$people) | is.null(input$info)) {
        } else {
            people_file <- input$people
            info_file <- input$info

            people <- read.csv(people_file$datapath, stringsAsFactors = F, encoding = "UTF-8-BOM")
            info <- read.csv(info_file$datapath, stringsAsFactors = F, fileEncoding = "UTF-8-BOM")

            rbind(people, info)
        }
    })

    output$plot <- renderImage({

        if(is.null(input$people) | is.null(input$info)) {
            outfile <- tempfile(fileext='.png')
            png(outfile, width = 1200, height = 800, res = 200)
            dev.off()

            list(src = outfile, width = 1200, height = 800)
        } else {
            people_file <- input$people
            info_file <- input$info

            people <- read.csv(people_file$datapath, stringsAsFactors = F, encoding = "UTF-8-BOM")
            info <- read.csv(info_file$datapath, stringsAsFactors = F, fileEncoding = "UTF-8-BOM")

            outfile <- tempfile(fileext='.png')
            png(outfile, width = 1200, height = 800, res = 200)
            plot(nrow(people), nrow(info), type="b")
            dev.off()

            list(src = outfile, width = 1200, height = 800, alt = "questions"))
        }
    }, deleteFile = TRUE)
}

# Run the application 
shinyApp(ui = ui, server = server)

这是我想要的伪代码示例：

[[ui]]

fileInput("people")
fileInput("info")

show(plot)
show(plot2)
show(df)


[[serverside]]

files <- source(input) {
  people <- read.csv(input$people, stringsAsFactors = F, encoding = "UTF-8-BOM")
  info <- read.csv(input$info, stringsAsFactors = F, encoding = "UTF-8-BOM")
}

contents <- plot(output) {
  some_function(files$people, files$info)
  plot(contents)
}

contents2 <- plot(output) {
  some_other_function(files$people, files$info)
  plot2 <- plot(contents2)
}

df <- table(output) {
  cbind(files$people, files$info)
}

这是我现在拥有的伪代码，效率不高。

[[ui]]

fileInput("people")
fileInput("info")

show(plot)
show(plot2)
show(df)


[[serverside]]

contents <- plot(input, output) {
  people <- read.csv(input$people, stringsAsFactors = F, encoding = "UTF-8-BOM")
  info <- read.csv(input$info, stringsAsFactors = F, encoding = "UTF-8-BOM")
  contents <- some_function(people, info)
  plot(contents)
} 

contents2 <- plot(input, output) {
  people <- read.csv(input$people, stringsAsFactors = F, encoding = "UTF-8-BOM")
  info <- read.csv(input$info, stringsAsFactors = F, encoding = "UTF-8-BOM")
  contents <- some_other_function(people,info)
  plot(contents)
}

df <- table(input, output) {
  people <- read.csv(input$people, stringsAsFactors = F, encoding = "UTF-8-BOM")
  info <- read.csv(input$info, stringsAsFactors = F, encoding = "UTF-8-BOM")
  cbind(people, info)

}

Answer 1

我将不得不同意 heds1 这有点难以获得您想要的结果。由于我们无法访问您的 csv，因此我创建了一些虚拟的。

可重现的数据/csvs：

write.csv2(x = 1:5, file = "people.csv", row.names = FALSE)
write.csv2(x = 6:10, file = "people2.csv", row.names = FALSE)

如果我对您的理解正确，您希望避免为每个上传的文件重复代码。 为了循环您的文件/数据集，我们必须将它们收集到一个数据结构中。

这样做的一种方法是允许上传多个文件：

fileInput(..., multiple = TRUE)

用户界面：

您可以在renderUI() 中使用循环创建的 ui 端：

output$plots <- renderUI({
  lapply(paste("people", 1:length(data)), plotOutput)
})

服务器端：

您可以通过循环创建的服务器端：

output[[paste("people", nr)]] <- renderPlot({
          plot(plotData)
})

本地分配

最后你将不得不使用local() 来避免只获取循环最后一次迭代的数据：

      local({
        LOCAL_VARIABLE <- data[[nr]]
        ....
      })

完整的可重现示例：

library(shiny)

write.csv2(x = 1:5, file = "people.csv", row.names = FALSE)
write.csv2(x = 6:10, file = "people2.csv", row.names = FALSE)

ui <- fluidPage(
  fileInput(inputId = "people", label = NULL, accept = ".csv",
            buttonLabel = "Browse...", placeholder = "people file", multiple = TRUE),
  uiOutput("plots")
)

server <- function(input, output, session) {
  observeEvent(input$people, {
    data <- lapply(input$people$datapath, read.csv2)    

    for(nr in 1:length(data)){
      local({
        plotData <- data[[nr]]
        output[[paste("people", nr)]] <- renderPlot({
          plot(plotData)
        })
      })
    }

    output$plots <- renderUI({
      lapply(paste("people", 1:length(data)), plotOutput)
    })
  })

}

shinyApp(ui, server)

编辑：

重用导入（和转换）的数据：

library(shiny)

write.csv2(x = 1:5, file = "people.csv", row.names = FALSE)

ui <- fluidPage(
  fileInput(inputId = "people", label = NULL, accept = ".csv",
            buttonLabel = "Browse...", placeholder = "people file", multiple = FALSE),
  plotOutput("plot"),
  tableOutput("table"),
  verbatimTextOutput("text")
)

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

  observeEvent(input$people, {
    data <- read.csv2(input$people$datapath)
    # DO LOTS OF OPERATIONS ON data

    global$data <- data
    # FROM HERE ON USE: global$data
  })

  output$plot <- renderPlot({
    req(global$data)
    plot(global$data)
  })

  output$table <- renderTable({
    global$data
  })

  output$text <- renderText({
    toString(global$data)
  })

}

shinyApp(ui, server)