使用dplyr计算数据框中连续三年总面积小于10的作物数量

library(dplyr)

df_biodiv %>%
  group_by(Year, CropName) %>%
  summarise(TotalArea = sum(Area)) %>%
  group_by(CropName) %>%
  mutate(VanishVariety = sum(TotalArea < 10 & lag(TotalArea, default = 0) < 10 & lead(TotalArea, default = 0) < 10)) %>%
  select(CropName, VanishVariety) %>%
  unique() -> vanishvarity