R闪亮错误:找不到对象输入

Question

以下代码是我的Shiny ui:

library(shiny)
shinyUI(fluidPage(

titlePanel("All Country Spend"),

  sidebarLayout(
    sidebarPanel(  selectInput("split", 
        label = "Choose Fill For the Chart",
        choices = c("Action.Obligation","Action_Absolute_Value"),
      selected = "Action.Obligation"
        )
            ),
    mainPanel(plotOutput("SpendChart"))
)
))

以下是服务器代码:

library(shiny)
library(ggplot2)

shinyServer(function(input, output) {

spend <- read.csv("data/Ctrdata.csv")
output$SpendChart <- renderPlot({

    Country <- spend$Principal.Place.of.Performance.Country.Name
    ggplot(spend, aes(x = Country, y = input$split)) + geom_bar(stat = "identity")

})

})

每次运行它我都会收到以下错误:

"eval中的错误(expr,envir,enclos):找不到对象'input'"

我试图渲染一个简单的条形图,它将在每个国家/地区的合同支出的净值和绝对值之间切换,但它不会从selectInput框中识别出名为"拆分"的输入.

这是我的数据框的示例:

data.frame(Country = c("Turk", "Turk", "Saudi", "Saudi", "Ger", "Ger"),
Action.Obligation = c(120,-345,565,-454, 343,-565),
Action_Absolute_Value = c(120,345,565,454,343,565))

Answer 1

The problem is with ggplot evaluating the variable in the context of the data frame provided, spend in your case. What you want is:

ggplot(spend, aes_string(x = "Country", y = input$split))

So your working server.R code is:

library(shiny)
library(ggplot2)

shinyServer(function(input, output) {

spend <- data.frame(Country = c("Turk", "Turk", "Saudi", "Saudi", "Ger", "Ger"),
                    Action.Obligation = c(120,-345,565,-454, 343,-565),
                    Action_Absolute_Value = c(120,345,565,454,343,565))

    output$SpendChart <- renderPlot({


        ggplot(spend, aes_string(x = "Country", y = input$split)) +
            geom_bar(stat = "identity")

    })

})

Obviously, you can replace the spend df with your CSV import.