阅读R Shiny中的文件

Question

所以我在R shiny中构建一个应用程序,要求用户上传.csv文件.一旦R shine读入,我不确定如何实际操作该对象使用.一般代码语法如下:

UI文件:

#ui.R
# Define UI for random distribution application 
shinyUI(fluidPage(

  # Application title
  titlePanel("ORR Simulator"),

  # Sidebar with controls to select the random distribution type
  # and number of observations to generate. Note the use of the
  # br() element to introduce extra vertical spacing
  sidebarLayout(
    sidebarPanel(
          fileInput('file1', 'Select the XXX.csv file',
                accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
      tags$hr(),
          fileInput('file2', 'Select the YYY.csv file',
                accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
      tags$hr(),
     numericInput("S", "Number of simulations to run:", 100),

       mainPanel(
plotOutput("plot")
    )
  )
))

服务器文件:

#server.R
library(shiny)

shinyServer(function(input, output) {

text1 <- renderText({input$file1})
text2 <- renderText({input$file2})

file1 = read.csv(text1)
file2 = read.csv(text2)

output$plot <- renderPlot({

plot(file1[,1],file2[,2])

})


})

所以我希望text1和text2能够保存包含文件路径的字符串,但似乎并非如此.Ultimatley我只是希望能够读取两个数据集,并从那里能够根据这两个数据集进行输出分析.

当然使用renderText也可能是错误的想法,因此非常感谢任何有关如何做得更好的建议.

Answer 1

这里有一个很好的例子http://shiny.rstudio.com/gallery/file-upload.html.但为了完整起见,我在下面列出了工作答案.关键是你应该使用引用文件file$datapath,并检查输入是否为NULL(当用户尚未上传文件时).

server.R

#server.R
library(shiny)

shinyServer(function(input, output) {

    observe({
        file1 = input$file1
        file2 = input$file2
        if (is.null(file1) || is.null(file2)) {
            return(NULL)
        }
        data1 = read.csv(file1$datapath)
        data2 = read.csv(file2$datapath)
        output$plot <- renderPlot({
            plot(data1[,1],data2[,2])
        })
    })

})

ui.R

library(shiny)

#ui.R
# Define UI for random distribution application 
shinyUI(fluidPage(

    # Application title
    titlePanel("ORR Simulator"),

    # Sidebar with controls to select the random distribution type
    # and number of observations to generate. Note the use of the
    # br() element to introduce extra vertical spacing
    sidebarLayout(
        sidebarPanel(
            fileInput('file1', 'Select the XXX.csv file',
                      accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
            tags$hr(),
            fileInput('file2', 'Select the YYY.csv file',
                      accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
            tags$hr(),
            numericInput("S", "Number of simulations to run:", 100)
        ),
        mainPanel(
            plotOutput("plot")
        )
    ))
)