R海拾遗-shiny3

setwd("D:\\360MoveData\\Users\\cmusunqi\\Documents\\GitHub\\R_and_python\\R")
counties <- readRDS("census-app/data/counties.rds")
head(counties)
# 包含州的名字和人口构成

# 安装地图包
# install.packages(c("maps", "mapproj"))
# maps和mapproj是脚本使用到的包
library(maps)
library(mapproj)
# 使用预先写好的脚本绘制地图
source("census-app/helpers.R")
counties <- readRDS("census-app/data/counties.rds")
# 各县的数据绘制成地形图。这里用深绿色表示各县白人居民的比例。
percent_map(counties$white, "darkgreen", "% White")

# 接下来使用shiny控件
library(shiny)
ui <- fluidPage(
  titlePanel("censusVis"),
  
  sidebarLayout(
    sidebarPanel(
      helpText("Create demographic maps with
        information from the 2010 US Census."),
      
      selectInput("var", 
                  label = "Choose a variable to display",
                  choices = c("Percent White", "Percent Black",
                              "Percent Hispanic", "Percent Asian"),
                  selected = "Percent White"),
      
      sliderInput("range", 
                  label = "Range of interest:",
                  min = 0, max = 100, value = c(0, 100))
    ),
    
    mainPanel(plotOutput("map"))
  )
)

# Server
# 通过server代码连接输出字段
server <- function(input, output) {
  # 定义输出图
  output$map <- renderPlot({
    data <- switch(input$var, 
                   "Percent White" = counties$white,
                   "Percent Black" = counties$black,
                   "Percent Hispanic" = counties$hispanic,
                   "Percent Asian" = counties$asian)
    color <- switch(input$var, 
                    "Percent White" = "darkgreen",
                    "Percent Black" = "black",
                    "Percent Hispanic" = "darkorange",
                    "Percent Asian" = "darkviolet")
    
    legend <- switch(input$var, 
                     "Percent White" = "% White",
                     "Percent Black" = "% Black",
                     "Percent Hispanic" = "% Hispanic",
                     "Percent Asian" = "% Asian")
    # 这里是绘图的函数
    percent_map(var = data, color , legend, max =input$range[1] ,input$range[2])
  })}


shinyApp(ui, server)