Question

我一直试图让我的第一个Shiny App工作，但是我收到一条错误，上面写着“错误：参数”mainPanel“缺失，没有默认值”

我不知道该怎么做。

ui.R：

library(shiny) 

shinyUI(fluidPage(
titlePanel(title = h4("Katrina Data Shiny Application - a histogram", align = "center")),
sidebarLayout(

    sidebarPanel(

      selectInput("var", 
              "1. Select the variable from the katrina dataset", 
              choices = c("flood depth", "log_medinc"),
              selected = "flood_depth"),

      sliderInput("bins", 
              "2. Select the number of bins for the histogram", 
              min=5, 
              max=50, 
              value=15
              )

      )
  ),

    mainPanel(
  plotOutput("myhist"))

)
)

我的Server.R：

library(shiny)

shinyServer(
  function(input, output) {



katrina = read.csv("katrina.csv")

output$myhist <- renderPlot ({
  data <- switch(input$var,
      "flood depth" = katrina$flood_depth,
      "log_medinc" = katrina$log_medinc)
  color <- switch(input$var,
      "flood depth" = "darkgreen",
      "log_medinc" = "deepskyblue"),
  legend <- switch(input$var,
      "flood depth" = "flood depth",
      "log_medinc" = "log_medinc")

  hist(var = data, color = color, l=input$bins+1, legend.title = legend)


    })

  }

)

Answer 1

Google搜索错误会将我引导至the following SO question。问题是mainPanel应该在sideBarLayout内调用。随便看一下，看起来你这样做，但仔细检查括号后发现你实际上并没有。正确的ui.R应为：

shinyUI(fluidPage(
  titlePanel(title = h4("Katrina Data Shiny Application - a histogram", align = "center")),
  sidebarLayout(

    sidebarPanel(

      selectInput("var", 
                  "1. Select the variable from the katrina dataset", 
                  choices = c("flood depth", "log_medinc"),
                  selected = "flood_depth"),

      sliderInput("bins", 
                  "2. Select the number of bins for the histogram", 
                  min=5, 
                  max=50, 
                  value=15
      )

    ),
    mainPanel(
      plotOutput("myhist")
    )
  )
)
)

导入CSV的闪亮应用程序以进行直方图

1 个答案: