Question

我的问题如下，我怀疑它有一个简单的解决方案。但是，我查看了create reactive function from user input和Reactive Function Parameter，但这些都没有回答我的问题。

我有一张图表，其X轴和Y轴可能会根据用户输入而改变。用户可以点击图表，我有一个文字显示，上面写着＆＃39;你选择了一个（x标签的名称）值为xxx，和一个（y标签的名称） yyy＆＃39;的价值。显然，如果x或y标签的名称以元音开头，我想使用＆＃39; an＆＃39;而不是＆＃39;。目前我已将此功能两次写入服务器模块，但这并不是非常优雅。

有没有办法在服务器功能中定义一个功能，我只需要将标签名称发送到该功能，而这只会返回＆＃39; a＆＃39;或者＆＃39;＆＃39;？代码如下。请注意，Pokemon数据集随着highcharter包一起旅行，可以从CRAN下载。

library(ggplot2)
library(highcharter)

myData <- pokemon

ui <- fluidPage(
  # Some custom CSS for a smaller font for preformatted text
  tags$head(
    tags$style(HTML("
                    pre, table.table {
                    font-size: smaller;
                    }
                    "))
    ),
  tags$head(tags$style(type = "text/css", ".shiny-text-output, .well{background-color: #EFF8CD;}")),

  fluidRow(
    column(width = 3
           ),
    column(width = 5,
           plotOutput("plot1", height = 450,
                      # Equivalent to: click = clickOpts(id = "plot_click")
                      click = "plot_click"
           )
    ),
    column(width = 4,
           ## Text output here.
             wellPanel(
               h4("Your results"),
               htmlOutput("chartDetails")
             )
           )
  )
)


server <- function(input, output) {
  output$plot1 <- renderPlot({
      ggplot(myData, aes(weight, attack)) + geom_point()
    }
  )

  ## Extract some values when plot is clicked
  inputX <- reactive({
    if (is.null(input$plot_click$x))
        {
          -999
          }
    else
      {
        round(input$plot_click$x, 0)
      }
    })
  inputY <- reactive({
    if (is.null(input$plot_click$y))
    {
    -999
    }
    else
    {
     round(input$plot_click$y, 0) 
    }
  })

  labelX <- eventReactive(input$plot_click, {
    input$plot_click$mapping$x
  })
  labelY <- eventReactive(input$plot_click,{
    input$plot_click$mapping$y
  })

  ## count the number of points that have a higher x and y.
  mySubset <- eventReactive(input$plot_click, {
    #myFirstSubset <- subset(myData, weight > inputX())
    subset(myData, labelX() > inputX() & labelY() > inputY())
    })


  ## Create relevant strings out of the inputX and inputY values.
  stringX <- reactive({
    if (inputX() > -999)
    {
      myString <- "You have selected"
      if (substr(labelX(), 1,1) %in% c("a", "e", "i", "o", "u"))
      {
        myString <- paste(myString, "an")
      }
      else
      {
        myString <- paste(myString, "a")
      }
      paste(myString, labelX(), "of", inputX())
    }
    else
    {
      ""
    }
  })

  stringY <- reactive({
    if (inputY() > -999)
    {
      myString <- "and"
      if (substr(labelY(), 1,1) %in% c("a", "e", "i", "o", "u"))
      {
        myString <- paste(myString, "an")
      }
      else
      {
        myString <- paste(myString, "a")
      }
      paste(myString, labelY(), "of", inputY())
    }
    else
    {
      ""
    }
  })

  stringCount <- reactive({
    if (inputY() > -999 && inputX() > -999)
    {
      paste("The number of records with higher",labelX(), "and", labelY(), "is", nrow(mySubset()))
    }
    else
    {
      ""
    }
  })

  ## Post the results to the chart details well.
  output$chartDetails <- renderUI({
    if (inputX() > -999 && inputY() > -999) {

    HTML(paste(stringX(), "<br>",
               stringY(), "<br>",
               stringCount()))
    }
    else
    {
      HTML("Click on the chart")
    }

  })

}

    shinyApp(ui, server)

Answer 1

Dieter Menne建议的简单解决方案如下：

UI /服务器功能之外：

myConnective <- function(aString) {
  if (substr(aString, 1,1) %in% c("a", "e", "i", "o", "u"))
  {
    myString <- "an"
  }
  else
  {
    myString <- "a"
  }
  return(myString)
}

然后在服务器功能中：

stringX <- reactive({
    if (inputX() > -999)
    {
      paste("You have selected", myConnective(labelX()), labelX(), "of", inputX() )
    }
    else
    {
      ""
    }
  })

Answer 2

我不确切知道这是否是你想要的，但你可以用两个函数代替元音函数

vowel <- function(myString, label){
    if (substr(label, 1,1) %in% c("a", "e", "i", "o", "u"))
   {
     myString <- paste(myString, "an")
   }
   else
   {
     myString <- paste(myString, "a")
   }
   return(myString)
 }

 ## Create relevant strings out of the inputX and inputY values.
 stringX <- reactive({
   if (inputX() > -999)
   {
     myString <- "You have selected"

     paste(vowel(myString,labelX()), labelX(), "of", inputX())
   }
   else
   {
     ""
   }
 })

 stringY <- reactive({
   if (inputY() > -999)
   {
     myString <- "and"

     paste(vowel(myString,labelY()), labelY(), "of", inputY())
   }
   else
   {
     ""
   }
 })

将参数传递给反应函数

2 个答案: