group_by(id) %>%
arrange(desc(date)) %>% #按日期降序
filter(row_number()==1) %>%
ungroup
参考:https://stackoverflow.com/questions/13279582/select-the-first-row-by-group
group_by(id) %>%
arrange(desc(date)) %>% #按日期降序
filter(row_number()==1) %>%
ungroup
参考:https://stackoverflow.com/questions/13279582/select-the-first-row-by-group