SHILY：将输入$var传递给ggplot2中的AES() [英] Shiny: passing input$var to aes() in ggplot2

问题描述

我正在尝试编写一款闪亮的应用程序，根据年龄(年龄)或性别(性别)类别绘制变量Val的密度图表。用户在下拉菜单中选择"性别"或"年龄"，我一直在尝试使用gglot和ggvis中的fill = input$Group_select。

在gglot中：

output$plot <- renderPlot(ggplot(gdat[gdat$GFR==input$GFR_select,]) + 
                      aes(x= VAL, fill=input$Group_select) +
                      geom_density(adjust=input$slider1))

edit：正如docendo指出的，可以使用aes_string：

为gglot修复此问题

output$plot <- renderPlot(ggplot(gdat[gdat$GFR==input$GFR_select,]) + 
                              aes(x= VAL) +
                              geom_density(adjust=input$slider1, aes_string(fill=input$Group_select))): 

在ggvis中：

gvis <- reactive(subset(gdat, GFR==input$GFR_select) %>% 
                 ggvis(x = ~VAL) %>% group_by_(input$Group_select) %>%
                 layer_densities(adjust = input$slider1) %>%
                 add_axis("y", title = "Density", ticks="none") %>%
                 scale_numeric("x", domain = c(0, 230)) ) 
gvis %>% bind_shiny("ggvis", "ggvis_ui")

解决方案：使用as.name(输入$Group_SELECT)将正确呈现图形！

这是呈现的内容：Imgur link to shiny output。有趣的是，GROUP_BY_似乎正确解释了输入$GROUP_SELECT，而输入$GROUP_SELECT在fill=input$Group_select

中被视为常量

关于如何正确渲染绘图有什么建议吗？

以下是完整的闪亮代码：

ui.R

library(shiny)
library(ggplot2)
library(dplyr)
library(ggvis)
shinyUI(fluidPage(
  titlePanel("eGFR in the ARIC study"),
  sidebarPanel(
    selectInput("Group_select",
                label=h3("By-Variable"),
                choices=c("AGE","SEX","ALL"),
                selected="SEX"),
    selectInput("GFR_select",
                label=h3("Creatinine Measure"),
                choices=c("BOTH", "CREATININE", "CYSTATIN", "MDRD"),
                selected="MDRD"),
    sliderInput("slider1", label = h3("Bandwith Adjustment"),
                min = 0.5, max = 4, value = 1)
  ),
  mainPanel(
    uiOutput("ggvis_ui"),
    ggvisOutput("ggvis"),
    plotOutput("plot")
  )
))

server.R

library(shiny)
source("helpers.R")
shinyServer(function(input, output) {
  gvis <- reactive(subset(gdat, GFR==input$GFR_select) %>% 
                     ggvis(x = ~VAL, fill = ~input$Group_select) %>% group_by_(input$Group_select) %>%
                     layer_densities(adjust = input$slider1) %>%
                     add_axis("y", title = "Density", ticks="none") %>%
                     scale_numeric("x", domain = c(0, 230)) ) 
  gvis %>% bind_shiny("ggvis", "ggvis_ui")
  output$plot <- renderPlot(ggplot(gdat[gdat$GFR==input$GFR_select,]) + 
                          aes(x= VAL, fill=input$Group_select) +


      geom_density(adjust=input$slider1))
})

推荐答案

我不确定这是否仍是一个悬而未决的问题，但aes_string的替代方案是将字符串转换为符号：

library(ggplot2)

# usually you can put all the shared aesthetics in the first line
ggplot(mtcars, aes(mpg, hp, colour = cyl)) +
  geom_point()

# when the input is a string, you can use aes_string(), but you'd
# have to enter the string var separately, or change all vars..

input <- "cyl"

ggplot(mtcars, aes(mpg, hp)) +
  geom_point(aes_string(colour = input))

# or
# ggplot(mtcars, aes_string("mpg", "hp", colour = input)) +
#  geom_point()

# you can put the converted string var in the normal aes()
ggplot(mtcars, aes(mpg, hp, colour = !!as.symbol(input))) +
  geom_point()

# note: as.name() and as.symbol() are aliases

由reprex package(v0.2.0)创建于2018-11-05。

这篇关于SHILY：将输入$var传递给ggplot2中的AES()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！