如何在不同的ggplot类型之间切换？答案

【问题标题】：How to switch between different ggplot types?如何在不同的ggplot类型之间切换？
【发布时间】：2020-12-22 08:45:43
【问题描述】：

我想要一个应用程序来绘制不同类型的数据（如线、点、箱线图）。

让我们考虑一下我的代码：

library(shiny)
library(quantmod)

start <- as.Date("2013-01-01")
end <- as.Date("2016-10-01")
# Apple stock
getSymbols("AAPL", src = "yahoo", from = start, to = end)
apple <- AAPL$AAPL.Close

### Define UI for application
ui <- fluidPage(

  # Sidebar panel
  sidebarPanel(
    selectInput("type",
      label = "1. Select plot type",
      choices = c("Line" = "geom_line()", "Dot" = "geom_point()", "Boxplot" = "geom_boxplot()"),
      selected = 3
    )
  ),

  # Main Panel
  mainPanel(
    plotOutput("sp")
  )
)





server <- function(input, output) {
  output$sp <- renderPlot({
    colm <- as.numeric(apple)
    ggplot() +
      aes(x = 1:length(colm), y = colm) +
      geom_line() +
      xlab(NULL)
  })
}

# Run the application
shinyApp(ui = ui, server = server)

而且我不确定我在server 中输入了什么才能在这些不同类型之间切换。我尝试使用if 语句和get(input$type)，但这两个选项都给我带来了错误。

总结 - 我如何编写我的应用程序，以便可以在不同的绘图类型（线、点、箱线图）之间切换，如图所示？

【问题讨论】：

标签： r ggplot2 shiny

【解决方案1】：

可以这样实现。你可以例如使用switch 语句根据类型分配geom_xxx

library(shiny)
library(quantmod)
library(ggplot2)

start <- as.Date("2013-01-01")
end <- as.Date("2016-10-01")
# Apple stock
getSymbols("AAPL", src = "yahoo", from = start, to = end)
apple <- AAPL$AAPL.Close

### Define UI for application
ui <- fluidPage(

  # Sidebar panel
  sidebarPanel(
    selectInput("type",
      label = "1. Select plot type",
      choices = c("Line" = "line", "Dot" = "point", "Boxplot" = "box"),
      selected = 3
    )
  ),

  # Main Panel
  mainPanel(
    plotOutput("sp")
  )
)

server <- function(input, output) {
  output$sp <- renderPlot({
    colm <- as.numeric(apple)
    geom <- switch(input$type,
      line = geom_line(),
      point = geom_point(),
      box = geom_boxplot()
    )
    ggplot() +
      aes(x = 1:length(colm), y = colm) +
      geom +
      xlab(NULL)
  })
}

# Run the application
shinyApp(ui = ui, server = server)

【讨论】：

【解决方案2】：

您可以使用match.fun 找到要应用的功能：

library(shiny)
library(quantmod)

start <- as.Date("2013-01-01")
end <- as.Date("2016-10-01")
# Apple stock
getSymbols("AAPL", src = "yahoo", from = start, to = end)
apple <- AAPL$AAPL.Close

### Define UI for application
ui <- fluidPage(
  # Sidebar panel
  sidebarPanel(
    selectInput("type",
                label = "1. Select plot type",
                choices = c("Line" = "geom_line", 
                            "Dot" = "geom_point", "Boxplot" = "geom_boxplot"),
                selected = 3
    )
  ),
  
  # Main Panel
  mainPanel(
    plotOutput("sp")
  )
)

server <- function(input, output) {
  output$sp <- renderPlot({
    colm <- as.numeric(apple)
    p <- ggplot() + aes(x = 1:length(colm), y = colm) + xlab(NULL)
    p + match.fun(input$type)()
      
  })
}

# Run the application
shinyApp(ui = ui, server = server)

【讨论】：