我有一个这样的数据框：
我想基于Shape_Area和number_of_clusters提取行。
对于ID_12：9，number_of_clusters为1。因此，需要对具有最大ID_12==9的{{1}}行进行切片。对于ID_12：73，有4个聚类，但有5个观测值。因此，基于Shape_Area的4个最大观测值将出现在结果数据框中。
我已经尝试过了，但是似乎不能正常工作：
Shape_Area根据两列保留不同数量的重复行
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问答
a710262403 回答：根据两列保留不同数量的重复行
df %>% group_by(ID_12) %>%
# sort by area in decreasing order for each ID_12
arrange(desc(Shape_Area),.by_group=TRUE) %>%
# create a new column called rank that stores the row number
# since we sorted in decreasing order by area,for each group,the row with largest area will have rank=1,and so on
mutate(rank = row_number()) %>%
# only take rows that have rank <= number_of_clusters
filter(rank <= number_of_clusters) %>%
# only select columns in the original dataframe
select(names(df))