1

我正在使用 R 并且我有一个如下所示的数据框：

df<-data.frame(
    tree_id=c("t1","t1","t1","t1","t1","t1","t1","t1","t1","t2","t2","t2","t2","t2","t2","t2","t2","t2"),
    branch_id=c("b1","b1","b1","b1","b1","b1","b1","b3","b3","b1","b1","b1","b1","b2","b2","b2","b2","b2"),
    bud_id_rank=c("1","2","4","7","9","12","15","1","3","1","2","5","9","1","5","7","8","12")
    )

我想添加一个名为“new_rank”的新列，它基于
branch_id 和 tree_id 从 1 开始升序。结果应该是这样的：

df<-data.frame(
    tree_id=c("t1","t1","t1","t1","t1","t1","t1","t1","t1","t2","t2","t2","t2","t2","t2","t2","t2","t2"),
    branch_id=c("b1","b1","b1","b1","b1","b1","b1","b3","b3","b1","b1","b1","b1","b2","b2","b2","b2","b2"),
    bud_id_rank=c("1","2","4","7","9","12","15","1","3","1","2","5","9","1","5","7","8","12"),
    new_rank=c("1","2","3","4","5","6","7","1","2","1","2","3","4","1","2","3","4","5")

    )

是否有任何功能可以快速使用例如 plyr 包？

提前致谢

4

1 回答 1

2

如果您现在已经使用哪个软件包，我想知道为什么您自己无法弄清楚。

library(plyr)
ddply(df,.(tree_id,branch_id), transform, new_rank = seq_along(branch_id))

如果您的数据集很大，data.table 会更快：

library(data.table)
DT <- as.data.table(df)
DT[, new_rank:=seq_along(bud_id_rank), by=list(tree_id, branch_id)]
于 2013-05-28T11:24:50.030 回答