使用addLayersControl函数时出错

Question

我尝试使用addLayersControl函数创建2个可选图层。但是，有一个错误。我想得到帮助。

.carousel {top: 0px;}

错误是：

        popup_LU <- paste0("<strong>Use Name: </strong>", 
                             LandUse$name, 
                             "<br><strong>Link: </strong>", 
                             LandUse$url)

          popup_NationalPark<-paste0("<strong>Use Name:</strong>",
                                     NationalPark$name,
                                     "<br><strong>National Park Area: 
                                     </strong>",
                                     NationalPark$area)


          pal <- colorQuantile("YlOrRd", NULL, n = 9)
          gmap <- leaflet(data = cancermap) %>%
            # Base groups
            addTiles() %>%
            setView(lng = -105, lat = 40, zoom = 4) %>% 
            addPolygons(fillColor = ~pal(rate), 
                        fillOpacity = 0.8, 
                        color = "#BDBDC3", 
                        weight = 1,
                        popup = popup_dat,
                        group="Cancer Rate/100,000 by Counties") %>% 

            # Overlay groups
            addMarkers(data=LandUse,lat=~lat, lng=~lng, popup=popup_LU, 
            group = "Land Use Sites") %>% 
            addCircleMarkers(data=NationalPark, lat=~lat, lng=~lng,color = 
            "green",popup = popup_NationalPark,group="National Park 
            Sites")%>% 

            # Layers control
            addLayersControl(
              baseGroups = c("Cancer Rate/100,000 by Counties"),
              overlayGroups = c("Land Use Sites","National Park Sites"),
              options = layersControlOptions(collapsed = FALSE)
            )

我的数据的负责人是：

     +       addLayersControl(
     +       baseGroups = c("Cancer Rate/100,000 by Counties"),
     +       overlayGroups = c("Land Use Sites","National Park Sites"),
     +      options = layersControlOptions(collapsed = FALSE)
     +                 )
      Error in cut.default(x, binsToUse, labels = FALSE, include.lowest = 
      TRUE,  : 
      'x' must be numeric