闪亮 - 根据用户输入更改图形上的变量

Question

我希望用户能够 select 哪个变量位于图表的 x 轴上。我的数据框如下所示：

> linegraphdata
   Year   E_coli Rain_Intensity Water_Temperature Dew_Point  Humidity Wind_Speed Barometric_Pressure Visibility Cloud_Cover
1  2006 181.4173    0.004077910          79.51720  60.08460 0.6747836   8.092537            1015.748   9.108940   0.5146045
2  2007 212.3498    0.005503364          80.36213  60.06608 0.6597432   6.074101            1015.417   9.173431   0.5019472
3  2008 127.0755    0.003195506          77.77268  58.15240 0.6559700   7.855993            1014.482   9.590509   0.5037079
4  2009 151.2129    0.004728056          74.56725  55.57986 0.6704676   6.278484            1014.511   9.389780   0.5461991
5  2010 142.9604    0.005628907          80.73180  61.37344 0.6662863   6.263983            1014.919   9.536397   0.4672130
6  2011 121.5559    0.005370608          79.44271  60.18298 0.6682699   6.879726            1013.199   9.467782   0.4891249
7  2012 126.4385    0.002568511          80.99142  57.04450 0.5765744   7.416897            1014.416   9.767905   0.3841238
8  2013 142.2380    0.004249872          76.72413  58.13510 0.6703193   7.058155            1015.610   9.451731   0.4211622
9  2014 139.4780    0.006628609          74.93213  58.53608 0.7117897   6.342423            1014.847   9.318628   0.3082917
10 2015 127.3011    0.004109462          75.38712  58.15503 0.7069821   7.058145            1014.534   9.378120   0.3086044
11 2016 123.7218    0.003886790          80.46863  63.90303 0.7176918   6.508438            1014.887   9.648991   0.2763920

问题是，Shiny 正在接受输入 $ 预测器的面值，并且只是绘制变量名称而不是附加到该变量名称的值列表。无法识别 selected 变量名称与包含值的数据框相关联。

注意：我希望第一个图表是静态的。我只想改变第二张图。

这是应用运行时的样子： Static image of app

这是我的应用程序代码：

library(shiny)
library(ggplot2)
library(gridExtra)

linegraphdata = read.csv("linegraphdata.csv")

predictor_options <-
  c(
    "Rain_Intensity",
    "Water_Temperature",
    "Dew_Point",
    "Humidity",
    "Wind_Speed",
    "Barometric_Pressure",
    "Visibility",
    "Cloud_Cover"
  )

ui <- fluidPage(fluidRow(
  column(12, offset = 0, tags$h1("Pick a Predictor:")),
  column(
    12,
    offset = 0,
    tags$h4(
      "Which elements of the environment trend with ",
      tags$i("E. coli"),
      " levels? Look for
      the predictor whose line graph peaks and valleys with the average",
      tags$i("E. coli"),
      "levels. "
    )
  ),
  column(4, offset = 0,
         ########################## HERE IS RELEVANT CODE:
         wellPanel(
           selectInput("predictor", "Select a Predictor", choices = predictor_options)
         )),
  column(10,
         plotOutput("graph3"))
))

server <- function(input, output) {
  observeEvent(input$predictor, {
    plot1 <-
      ggplot(data = linegraphdata, aes(x = Year, y = E_coli)) + geom_line() + theme_bw()
    ########################## HERE IS RELEVANT CODE:
    plot2 <-
      ggplot(data = linegraphdata, aes(x = Year, y = input$predictor)) + geom_line() + theme_bw()
    output$graph3 <- renderPlot({
      grid.arrange(plot1, plot2, ncol = 1)
    })
  })
}

shinyApp(ui = ui, server = server)

Answer 1

我找到答案了！我只需要添加一些行，将输入绑定回数据框（在服务器端）。我将输入存储在 reactive() 函数中并去掉了 observeEvent() 函数。

server <- function(input, output) {

  data <- reactive({
if ( "Rain_Intensity" %in% input$predictor) return(linegraphdata$Rain_Intensity)
if ( "Water_Temperature" %in% input$predictor) return(linegraphdata$Water_Temperature)
if ( "Dew_Point" %in% input$predictor) return(linegraphdata$Dew_Point)
if ( "Humidity" %in% input$predictor) return(linegraphdata$Humidity)
if ( "Wind_Speed" %in% input$predictor) return(linegraphdata$Wind_Speed)
if ( "Barometric_Pressure" %in% input$predictor) return(linegraphdata$Barometric_Pressure)
if ( "Visibility" %in% input$predictor) return(linegraphdata$Visibility)
if ( "Cloud_Cover" %in% input$predictor) return(linegraphdata$Cloud_Cover)

  })
plot1 <- ggplot(data= linegraphdata, aes(x=Year, y=E_coli)) + geom_line() + theme_bw()
plot2 <- ggplot(data = linegraphdata, aes(x=Year, y=data())) + geom_line() + theme_bw()
output$graph3 <- renderPlot({grid.arrange(plot1, plot2, ncol=1)})

}

Answer 2

如果您的 input$predictor 值完全与您的 linegraphdata data.frame 的列名匹配，您还可以使用 aes_string 来自ggplot（使用字符串或引用 names/calls 来定义美学映射）：

plot2 <- ggplot(data = linegraphdata, aes_string(x = "Year", y = input$predictor)) + geom_line() + theme_bw()

这样你就不需要具有多个 if 语句的反应函数。

闪亮 - 根据用户输入更改图形上的变量

Shiny - Changing Variables on a Graph Based on User Input

variables

shiny

interactive

linegraph