Question

我想在我的Shiny App中绘制一个绘制的3D图形，但只绘制具有在输入范围滑块范围内的值的数据。但是我想在滑块范围内没有值时阻止绘图 - 当前没有输入时会导致以下错误：

Warning: Error in UseMethod: no applicable method for 'plotly_build' applied       
to an object of class "NULL"

或在示例代码中：

Error in : length(Lab) == 3L is not TRUE

这是一个示例代码，它与原始问题有类似的错误：

library(shiny)
library(plotly)

d = diamonds[1:100,]

ui = fluidPage(
headerPanel("Data"),

sliderInput(inputId="slider", label = "Choose a range", value =c(0,max(d$price)),
          min = 0,max = max(d$price)),

# saves space for the plot in the user interface. Id allows communication
plotlyOutput(outputId="trendPlot", width="100%", height=800)

)

server = function(input, output)
{
NROF = reactiveValues(test = 1)

output$trendPlot= renderPlotly({
d_sub=d[d$price >= input$slider[1] & d$price <= input$slider[2],]
NROF = nrow(d) 
if(NROF != 0)
{
  plot_ly(d_sub, x=d_sub$cut, y=d_sub$color, z=factor(d_sub$color),
          type='scatter3d', mode='markers',
          sizemode='diameter', size=d_sub$price, color=d_sub$price,colors = 'Set1')

}
})
}

shinyApp(ui=ui, server=server)

解决方案：我使用反应值时犯了一个错误 - 应该是NROF $ TEST

Answer 1

您正在寻找req()或validate()之类的声音：

http://shiny.rstudio.com/articles/req.html

http://shiny.rstudio.com/articles/validation.html

library(shiny)
library(plotly)

d <- diamonds[1:100,]

ui <- fluidPage(
  headerPanel("Data"),
  sliderInput(inputId="slider",
              label = "Choose a range",
              value =c(0,max(d$price)),
              min = 0,max = max(d$price)),
  # saves space for the plot in the user interface. Id allows communication
  plotlyOutput(outputId="trendPlot",
               width="100%", height=800)

)

server <- function(input, output) {
  output$trendPlot <- renderPlotly({
    d_sub <- d[d$price >= input$slider[1] & d$price <= input$slider[2],]
    req(nrow(d_sub) > 0)
    # validate(need(nrow(d_sub) > 0, "No data selected!"))

    plot_ly(d_sub, x=d_sub$cut, y=d_sub$color, 
            z=factor(d_sub$color), type='scatter3d', 
            mode='markers', sizemode='diameter', 
            size=d_sub$price, color=d_sub$price,
            colors = 'Set1')
  })
}

shinyApp(ui=ui, server=server)

Answer 2

我试图重现它。我的建议是有一个小错字（你的意思是NROF = nrow(d_sub)而不是NROF = nrow(d)）。另外，您没有包含else案例的任何返回值。

这对你有帮助吗？

server = function(input, output)
{
  NROF = reactiveValues(test = 1)

  output$trendPlot= renderPlotly({
    d_sub=d[d$price >= input$slider[1] & d$price <= input$slider[2],]
    NROF = nrow(d_sub)
    if(NROF != 0)
    {
      plot_ly(d_sub, x=d_sub$cut, y=d_sub$color, z=factor(d_sub$color),
              type='scatter3d', mode='markers',
              sizemode='diameter', size=d_sub$price, color=d_sub$price,colors = 'Set1')

    } else {
      plot_ly(type='scatter3d')
    }
  })
}

闪亮 - 如果使用滑块

2 个答案: