因此，我尝试创建一个漂亮的应用程序，在其中使用sf数据绘制印度Map。我上传了一个包含多列的数据集。因此，我要求用户选择列。但是，当我将该输入提供给geom_sf(fill = input$select_topic)时，它首先认为列名是一个字符值，因此我使用geom_sf(fill = .data$input$select_topic)或geom_sf(fill = ,data[[input$select_topic]] )，这会给我**error : Can't subset .data outside of a data mask context.**
下面是代码：

library(shiny)
library(tidyverse)
library(sf)

# joining the main datset and the sf dataset 

map_data <- read.csv("D:\\R Projects\\R experimental\\dashboard\\app-1\\app-1\\data\\edu_data.csv")
map_data <- as.data.frame(map_data)
map_data_2 <- left_join(India, map_data, by = "state_ut")

# Define UI ----
ui <- fluidPage(
  titlePanel("My Shiny App"),
  
  sidebarLayout(position = "right",
    sidebarPanel(
      
      selectInput("select_year", label = "Select Year", 
                  choices = list("2012-13" = 2012,
                                 "2013-14" = 2013, 
                                 "2014-15" = 2014,
                                 "2015-16" = 2015), selected = 2013),
      selectInput("select_topic", label = "Select Category", 
                  choices = list("Drinking Water Facility" = 'water_faci', 
                                 "Girl's Toilet Facility" = 'gtoi_faci',
                                 "Boy's Toilet Facility" = 'btoi_faci',
                                 "Electricity Connection" = 'elec_faci',
                                 "Computer availability" = 'comp_faci',
                                 "Overall Facilities" = 'all_faci',
                                 "Gross Enrollment" = 'gross_enroll',
                                 "Drop-out Rate" = 'drop_rate' 
                                 ), selected = "Drinking Water Facility")
      
    mainPanel(
      h1("Maps"),
      textOutput("selected_year"),
      textOutput("selected_category"),
      plotOutput("map")
      )
  )
  
)

# Define server logic ----
server <- function(input, output) {
  
  output$selected_year <- renderText({
    paste("You have selected the year:", input$select_year)
  })
  
  
  output$selected_category <- renderText({
    paste("You have selected category:", input$select_topic)
  })
  
  })
  output$map <- renderPlot({
    x <- map_data_2 %>% filter(., year == input$select_year)
    
    ggplot(x, aes(label = state_ut)) +
      geom_sf( fill = .data$input$select_topic ) +
      scale_fill_distiller(palette = "GnBu", 
                           direction= 1, 
                           na.value="grey") +
      theme_map() + 
      theme( plot.title = element_text(size=22), 
             legend.position = "left", 
             legend.justification ='left') 
  })  
  
}

# Run the app ----
shinyApp(ui = ui, server = server)

• • 这是我需要选择其列的数据集**

| 状态|年份|水相|组成|btoi_相|gtoi_面|电_面|全相|总入组|下降率|
| - ------|- ------|- ------|- ------|- ------|- ------|- ------|- ------|- ------|- ------|
| 全印度|二〇一三年|九十五点四|二十四时零八分|八十六点五六分|九十一点二三分|五十六点七八分|七十块八一|七十九点八九|六点八八|
| 安达曼和尼科巴群岛|二〇一三年|九十八点六九|五十三点零六分|九十四点五二分|九十三点四四分|八十八点八六分|八十五七百一十四|九十六点八|六、二|
| 安得拉邦|二〇一三年|九十点三五分|二十九点五十七分|五十六点八八|八十一点三一分|九十点三四分|六十九点六九|七十八点九五分|八点一四|
| 阿鲁纳恰尔邦|二〇一三年|七十九点七九|二十四点二十八分|四十八点七三分|七十六点九|三十六点三十五分|五十三点二一|九十八块五八||
| 阿萨姆邦|二〇一三年|八十点三|八点八五分|六十点一七分|七十五点二八|十九点三十九分|四十八七百九十八|七十七点六八|十三时零四分|
| 比哈尔邦|二〇一三年|九十二点五三分|五点四十七分|七十三点四二|七十五点四一|九点九六分|五十一三五八|六十七点二四分||
| 昌迪加尔|二〇一三年|一百|九十五点八三|一百|一百|一百|九十九点一六六|九十四点一八分||
| 恰蒂斯加尔邦|二〇一三年|九十五点四十七分|九点八|八十二点八五分|九十四点一|五十七点二八|六十七点九|八十九点九八分||

output$map <- renderPlot({
    x <- map_data_2 %>% filter(., year == input$select_year)

    ggplot(x, aes(label = state_ut)) +
      geom_sf( fill = input$select_topic ) +
      scale_fill_distiller(palette = "GnBu", 
                           direction= 1, 
                           na.value="grey") +
      theme_map() + 
      theme( plot.title = element_text(size=22), 
             legend.position = "left", 
             legend.justification ='left') 
  })

将产生一个Map，该Map将填充值作为数据集中存在的列。