通过在组内对列进行排序来重新排列数据框 [英] rearrange a data frame by sorting a column within groups

问题描述

执行以下任务的好方法是什么?

What is a good way to perform the following task?

我有一个数据框，例如:

I have a data frame, for example:

v2 <- c(4.5, 2.5, 3.5, 5.5, 7.5, 6.5, 2.5, 1.5, 3.5)
v1 <- c(2.2, 3.2, 1.2, 4.2, 2.2, 3.2, 2.2, 1.2, 5.2)
lvl <- c("a","a","a","b","b","b","c","c","c")
d <- data.frame(v1,v2,lvl)

> d
   v1  v2 l
1 2.2 4.5 a
2 3.2 2.5 a
3 1.2 3.5 a
4 4.2 5.5 b
5 2.2 7.5 b
6 3.2 6.5 b
7 2.2 2.5 c
8 1.2 1.5 c
9 5.2 3.5 c

在d$lvl的每个级别中，我想按d$v1的值对数据帧进行排序.所以我想得到

Within each level of d$lvl, I want to sort the data frame by value of d$v1. So I want to get

   v1  v2 l
3 1.2 3.5 a
1 2.2 4.5 a
2 3.2 2.5 a

5 2.2 7.5 b
6 3.2 6.5 b
4 4.2 5.5 b

8 1.2 1.5 c
7 2.2 2.5 c
9 5.2 3.5 c

推荐答案

我认为最直接的方法是

d[order(d$lvl,d$v1),]

给出

   v1  v2 lvl
3 1.2 3.5   a
1 2.2 4.5   a
2 3.2 2.5   a
5 2.2 7.5   b
6 3.2 6.5   b
4 4.2 5.5   b
8 1.2 1.5   c
7 2.2 2.5   c
9 5.2 3.5   c

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