运行R shinydashboard出现tagAssert函数body参数缺失报错如何解决

你遇到的报错本质是dashboardBody代码存在语法错误和结构不规范问题，导致R无法正常解析出完整的dashboardBody对象，调用dashboardPage时就会判定body参数缺失，抛出对应报错。具体问题如下：

• 所有嵌套组件的闭合括号缺失：你贴出的代码末尾缺少6个右括号，分别对应未闭合的tabPanel("Standard Deviation")、tabBox(id="tabs2")、tabPanel("Mean")、tabBox(id="tabs1")、column(width=6)、dashboardBody()层级的闭合符号
• 结构不符合shinydashboard规范：tabItem不能直接和column平级放在fluidRow下，所有tabItem必须包裹在tabItems()容器中，如果你需要同时存在全局固定内容和tab切换内容，要把全局内容放在tabItems()之外单独嵌套
• 嵌套逻辑错误：你将第二个tabBox（id="tabs2"）直接作为tabPanel("Mean")的唯一参数，既没有关闭第一个tabPanel也没有补充其他tab选项，组件结构完全混乱

dashboardBody(
  # 全局非切换内容
  fluidRow(
    column(width=6, 
           box(
             title = "Select a Number",
             solidHeader = TRUE,
             background = "yellow",
             status="warning",
             width = NULL,
             height = 312,
             sliderInput(inputId = "number",
                         label = "", 
                         value = 500, min = 25, max = 1000)),
           
           box(title = "Histogram",
               solidHeader=TRUE, 
               background = "light-blue",
               status="primary",
               width = NULL,
               plotOutput("hist", height = 250)),
           valueBoxOutput("meanBox"),
           valueBoxOutput("medianBox"),
           valueBoxOutput("sdBox")
    ),
    column(width = 6, 
           tabBox(
             title = "Central Tendency",
             id = "tabs1", height = 120, width = NULL,
             tabPanel("Mean", h2(textOutput("meantext"))),
             tabPanel("Median", h2(textOutput("mediantext")))
           ),
           tabBox(
             title = "Variability",
             id = "tabs2",height = 120, width = NULL,
             side = "right",
             tabPanel("Variance", h2(textOutput("vartext")),width = NULL),
             tabPanel("Standard Deviation", h2(textOutput("sdtext")), width = NULL)
           )
    )
  ),
  # tab切换内容容器
  tabItems(
    tabItem(
      tabName = "normal",
      fluidRow(
        box(title = "select a Number",
            solidHeader = TRUE,
            collapsible = TRUE,
            status = "warning",
            sliderInput(inputId = "normnumber",
                        label = "",
                        value = 500,min = 25, max = 1000)),
        box(title = "Density Plot",
            solidHeader = TRUE,
            background = "light-blue",
            status = "primary",
            plotOutput("density", height = 250)),
        infoBoxOutput("meanInfoBox"),
        infoBoxOutput("medianInfoBox"),
        infoBoxOutput("sdInfoBox")
      )
    )
  )
)

• 写完嵌套组件后可以通过RStudio的括号匹配功能（点击括号会高亮对应配对括号）检查是否有漏写的闭合符号
• 确认dashboardPage的三个参数dashboardHeader()、dashboardSidebar()、dashboardBody()都完整传入，没有拼写错误
• 侧边栏的menuItem对应的tabName要和tabItem的tabName完全一致，大小写敏感

内容的提问来源于stack exchange，提问作者Zach Paiz