闪亮的应用程序：无法根据用户输入绘制股票图表

Question

我试图在一个光亮的应用程序中使用Quantmod绘制股票图表，但出现以下错误：input $ stockInput两次尝试后下载失败。错误消息：HTTP错误404。不胜感激。

服务器：

library(quantmod)

shinyServer(function(input, output) {

  output$distPlot <- renderPlot({

    price <- getSymbols('input$stockInput',from='2017-01-01')
    plot(price)

})})

用户界面：

library(shiny)

shinyUI(fluidPage(


  titlePanel("Stock Chart"),


  sidebarLayout(
    sidebarPanel(

       #This is a dropdown to select the stock
       selectInput("stockInput", 
                   "Pick your stock:", 
                   c("AMZN","FB","GOOG","NVDA","AAPL"),
                   "AMZN"),selected = "GOOG"),

    # Show a plot of the generated distribution
    mainPanel(
       plotOutput("distPlot")
))))

谢谢。

Answer 1

您的代码需要进行一些更改。首先，当您在server.R中访问闪亮的UI对象时，应将其用作对象而不是带引号的字符

price <- getSymbols(input$stockInput,from='2017-01-01')

没有设置参数（getSymbols的值）的函数auto.assign = F在需要其数据的股票名称中创建一个新的xts对象，因此在下面的代码中，我将其与设置auto.assign = F，以便更容易访问对象price进行绘图。否则，您可能必须使用price在get()中获取值，然后按照我的评论进行绘制。

server.R

library(quantmod)

shinyServer(function(input, output) {

  output$distPlot <- renderPlot({

    price <- getSymbols(input$stockInput,from='2017-01-01', auto.assign = F)
    #plot(get(price), main = price) #this is used when auto.assign is not set by default which is TRUE
    plot(price, main = input$stockInput) # this is when the xts object is stored in the name price itself

  })})

ui.R

library(shiny)

shinyUI(fluidPage(


  titlePanel("Stock Chart"),


  sidebarLayout(
    sidebarPanel(

      #This is a dropdown to select the stock
      selectInput("stockInput", 
                  "Pick your stock:", 
                  c("AMZN","FB","GOOG","NVDA","AAPL"),
                  "AMZN"),selected = "GOOG"),

    # Show a plot of the generated distribution
    mainPanel(
      plotOutput("distPlot")
    ))))

希望它能澄清！