r - nearPoints 无法从 Shiny 的坐标信息中自动推断出 `xvar`

Question

我正在尝试使用 nearPoints 函数在鼠标点击附近的 ggplot 中找到点，但它不起作用。我使用下面的代码为 diamonds data.frame 创建了带有两个图的 Shiny 应用程序:

library(shiny)
library(ggplot2)
ui <- fluidPage(
mainPanel(
uiOutput("tb")
)
)
server <- function(input,output){

   output$diamonds1 <- renderPlot({

        print(ggplot(diamonds, aes(x=carat, y=price, col=clarity)) + 
                                geom_point(alpha=0.5)+ facet_wrap(~color, scales="free"))
   })
   output$diamonds2 <- renderPlot({

        print(ggplot(diamonds, aes(x=carat, y=price, col=clarity)) + 
                               geom_point(alpha=0.5)+ facet_wrap(~cut, scales="free"))
   }) 

   output$info <- renderPrint({

        nearPoints(diamonds, input$plot_click, threshold = 10, maxpoints = 1,
                   addDist = TRUE)
   })

output$tb <- renderUI({
tabsetPanel(tabPanel("First plot", 
                     plotOutput("diamonds1")),
            tabPanel("Second plot", 
                     plotOutput("diamonds2", click = "plot_click"), 
                     verbatimTextOutput("info"))) 
})
}
shinyApp(ui = ui, server = server) 

我在第二个情节中不断收到这个错误

Error: nearPoints: not able to automatically infer xvar from coordinfo

有什么建议吗？

Answer 1

这就是你想要我想的。您正在“打印”ggplot，这显然混淆了 nearPoints:

library(shiny)
library(ggplot2)
ui <- fluidPage(
  mainPanel(
    uiOutput("tb")
  )
)
server <- function(input,output){

  output$diamonds1 <- renderPlot({

    print(ggplot(diamonds, aes(x=carat, y=price, col=clarity)) + 
                            geom_point(alpha=0.5)+ facet_wrap(~color, scales="free"))
  })
  output$diamonds2 <- renderPlot({

    ggplot(diamonds, aes(x=carat, y=price, col=clarity)) + 
                     geom_point(alpha=0.5)+ facet_wrap(~cut, scales="free")
  }) 

  output$info <- renderPrint({
    nearPoints(diamonds,input$plot_click,threshold = 10, maxpoints = 1,addDist = TRUE)
  })

  output$tb <- renderUI({
    tabsetPanel(tabPanel("First plot", 
                         plotOutput("diamonds1")),
                tabPanel("Second plot", 
                         plotOutput("diamonds2", click = "plot_click"), 
                         verbatimTextOutput("info"))) 
  })
}
shinyApp(ui = ui, server = server) 

产生这个 - 注意 data.frame 输出是 diamonds 中靠近鼠标点击的点: