尝试创建一个反应图，该图将在闪亮中接受多个不同的输入答案

【问题标题】：Trying to create a reactive graph that will take in multiple different inputs in shiny尝试创建一个反应图，该图将在闪亮中接受多个不同的输入
【发布时间】：2020-01-01 14:02:05
【问题描述】：

我在侧边栏和主体中向闪亮的应用程序添加了多个选择输入，并希望创建一个图表，当任何这些输入被选择或更改时会发生变化，但我不断收到错误警告：错误: 结果的长度必须是 56127，而不是 0。

用户界面：

ui <- dashboardPage(
    dashboardHeader(title = "Human Trafficking"),

    dashboardSidebar(
        sidebarMenu(
            selectInput("Source", "Choose a Data Source: ", choices = " ", selected = NULL,
                        multiple = TRUE, selectize = TRUE, width = NULL, size = NULL),
            dateInput("startdate", "Start Date:", value = "2009-01-01", format = "dd-mm-yyyy",
                      min = "2009-01-01", max = "2019-08-26"),

            dateInput("enddate", "End Date:", value = "2019-08-27", format = "dd-mm-yyyy",
                      min = "2009-01-02", max = "2019-08-27"),
            selectInput("Nationality", "Select a nation: ", choices = " "),
            actionButton("button", "Apply")
        )
    ),

    dashboardBody(

        fluidRow(
            box(width = 4, solidHeader = TRUE,
                selectInput("traffickingType", "Choose a trafficking type: ", choices = " ", selected = NULL,
                            multiple = TRUE, selectize = TRUE, width = NULL, size = NULL)
            ),
            box(width = 4, solidHeader = TRUE,
                selectInput("traffickingSubType", "Choose a trafficking sub type: ", choices = " ", selected = NULL,
                            multiple = TRUE, selectize = TRUE, width = NULL, size = NULL)
            ),
            box(width = 4, solidHeader = TRUE,
                selectInput("gender", "Choose a gender: ", choices = " ", selected = NULL,
                            multiple = TRUE, selectize = TRUE, width = NULL, size = NULL)
            )
        ),
        fluidRow(
            box(width = 12,
                plotlyOutput('coolplot')
            )
        )
    )
)

服务器：

server <- function(input, output, session) {

  genderVic = sort(unique(ngo$Victim.Gender))
  updateSelectInput(session, "gender", choices = genderVic)

  traffickingSub = sort(unique(ngo$Trafficking.Sub.Type))
  updateSelectInput(session, "traffickingSubType", choices = traffickingSub)

  trafficking = sort(unique(ngo$Trafficking.Type))
  updateSelectInput(session, "traffickingType", choices = trafficking)

  traffickerNationalities = sort(unique(ngo$Trafficker.Nationality))
  updateSelectInput(session, "TraffickerNation", choices = traffickerNationalities)

  dataSource = sort(unique(ngo$Data.Provided.By))
  updateSelectInput(session, "Source", choices = dataSource)

  nationalities = sort(unique(ngo$Victim.Nationality))
  updateSelectInput(session, "Nationality", choices = nationalities)

  output$coolplot <- renderPlotly({
    ngo <-
      ngo %>%
      filter(Victim.Nationality == input$Nationality,
             Victim.Gender == input$gender,
             Trafficking.Type == input$traffickingType
      )

    p = ggplot(ngo, aes(x = Victim.Age, fill = Trafficking.Type)) + 
      geom_bar(position = "stack")
    ggplotly(p) %>%
      layout(showlegend = FALSE)
  })
}

所以目前它只调用三个输入来测试它，但仍然出现错误。

【问题讨论】：

标签： r ggplot2 shiny dplyr plotly

【解决方案1】：

在您的示例中选择性别和广告投放类型后，它应该会在显示错误后起作用。错误的原因是 renderPlotly 期望 input$traffickingType 和 input$gender 的值，但这些值以 NULL 开头。

为每个selectInputs 添加一个req：

    output$coolplot <- renderPlotly({
        ngo <-
            ngo %>%
            filter(Victim.Nationality == input$Nationality,
                   Victim.Gender == req(input$gender),
                   Trafficking.Type == req(input$traffickingType)
            )

        p = ggplot(ngo, aes(x = Victim.Age, fill = Trafficking.Type)) + 
            geom_bar(position = "stack")
        ggplotly(p) %>%
            layout(showlegend = FALSE)
    })

【讨论】：