我有一个R代码，它创建了一个由addPolylines()连接的点的瓣叶图。

library(shiny)
library(leaflet)

station = c("A", "B", "C", "D", "E", "F")
latitude = c(-1.63, -1.62, -1.62, -1.77, -1.85, -1.85)
longitude = c(34.3, 34.4, 34.7, 34.3, 34.5, 34.7)
big = c(0, 20, 60, 90, 50, 10)
small = c(100, 80, 40, 10, 50, 90)
colour = c("blue", "blue", "red", "red", "black", "black")
group = c("A", "A", "B", "B", "C", "C")

df = cbind.data.frame(station, latitude, longitude, big, small, colour, group)

colnames(df) = c("station", "latitude", "longitude", "big", "small", "colour", "group")


myMap = leaflet() %>%
    setView(lng = 34.4, lat = -1.653, zoom = 8) %>%
    addTiles()%>%

  addCircles(data = df,
             lng = ~ longitude, lat = ~ latitude,
             color = ~ colour,
             radius = 2000,
             stroke = TRUE,
             opacity = 5,
             weight = 1,
             fillColor = ~ colour,
             fillOpacity = 1)

for(group in levels(df$group)){
  myMap = addPolylines(myMap, 
                      lng= ~ longitude,
                      lat= ~ latitude,
                      data = df[df$group == group,], 
                      color= ~ colour,
                      weight = 3)
}

myMap

这正是我想要的，它看起来像这样：

但是，当我把这个放进一个R shiny应用程序时，Map就不会出现了，ui代码是：

fluidPage(

  theme = shinythemes::shinytheme("yeti"),

  titlePanel(title = "Polyline Map"))

    mainPanel("",
              helpText("This is the polyline map"),
              hr(),
              leafletOutput("myMap", height = 400, width = 600)

    )

服务器代码为：

function(input, output, session) {

  output$myMap = renderLeaflet({
    leaflet() %>%
      setView(lng = 34.4, lat = -1.653, zoom = 8) %>%
  addTiles()%>%

  addCircles(data = df,
               lng = ~ longitude, lat = ~ latitude,
               color = ~ colour,
               radius = 4000,
               stroke = TRUE, 
               opacity = 5,
               weight = 1,
               fillColor = ~ colour,
               fillOpacity = 0.5)

    for(group in levels(df$group)){
      myMap = addPolylines(myMap,
                           lng= ~ longitude,
                           lat= ~ latitude,
                           data = df[df$group==group,],
                           color= ~ colour,
                           weight = 3)
    }
  }

  )}

全局代码为：

library(shiny)
library(leaflet)

station = c("A", "B", "C", "D", "E", "F")
latitude = c(-1.63, -1.62, -1.62, -1.77, -1.85, -1.85)
longitude = c(34.3, 34.4, 34.7, 34.3, 34.5, 34.7)
big = c(0, 20, 60, 90, 50, 10)
small = c(100, 80, 40, 10, 50, 90)
colour = c("blue", "blue", "red", "red", "black", "black")
group = c("A", "A", "B", "B", "C", "C")

df = cbind.data.frame(station, latitude, longitude, big, small, colour, group)

colnames(df) = c("station", "latitude", "longitude", "big", "small", "colour", "group")

有人知道为什么会发生这种情况，以及我能做些什么来修复它吗？谢谢！