由于数据中存在NA，无法在R中绘制直方图

我正在创建一个闪亮的应用程序，其中有一个下拉列表，它将值发送到服务器以创建直方图

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

代码如下所示

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

用户界面：

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

服务器：

datasetInput <- reactive({ 
    switch(input$dataset, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{hist(rnorm(input$diamonds))
  })

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

因此，当我从下拉列表中选择任何内容并单击“提交”按钮时，它会显示出来

Error Msg: Listening on http://127.0.0.1:6691 Warning in rnorm(input$diamonds) : NAs introduced by coercion Warning: Error in rnorm: invalid arguments Stack trace (innermost first):   
    100: rnorm
     99: hist
     98: eventReactiveHandler [#10]
     78: output$hist
      4: <Anonymous>
      3: do.call
      2: print.shiny.appobj
      1: <Promise>

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

---

如何在创建直方图时避免NA？

您的问题与NAs无关。阅读该错误消息的第二部分：rnorm中的错误：无效参数堆栈跟踪最里面的第一个

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

问题是rnorm接受一个数值参数，该参数确定从正态分布生成多少随机数。您可以使用rnorInput$diamonds调用它，其中input$diamonds返回selectInput的选定值，所有这些值都是字符串：choices=cLength、Breath、Height，请选择一种类型

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

您的代码应该是：

datasetInput <- reactive({ 
    switch(input$diamonds, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  })
  output$hist <- eventReactive(input$action,{hist(rnorm(datasetInput()))
  })

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

---

您需要在rnorm调用中调用datasetInput，以便获得适当的数值，而不是输入$diamonds（以字符形式返回选择）

是的，实际问题在于rnorm方法。在这里，如果我们使用rnorm，它将给出相同的结果，而不考虑开关情况下的任何选择。为了得到准确的直方图，我们必须删除rnorm方法，然后调用datasetInput方法

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**

---

感谢@divi的帮助。您让我接近了解决方案。

您应该提供完整的用户界面和服务器，以便我们重现您的错误。

datasetInput <- reactive({ 
    switch(input$diamonds1, 
           "Length" = diamonds$x, 
           "Breath" = diamonds$y, 
           "Height" = diamonds$z,
           " Please Select a Type " = NULL) 
  }) 
  output$hist <- eventReactive(input$action,{**hist(datasetInput())**