问题描述
enter image description here标题绝对不足以理解我的问题。简而言之,这是我的数据:
|ID | group |
|---|-------|
| 1 | Banana|
| 2 | Apple |
| 3 | Apple |
| 4 | Apple |
| 5 | Banana|
| 6 | Banana|
| 7 | Apple |
| 8 | Apple |
现在我想创建一个按组编号的变量,但是在新的观察之后它不应再次从 1 开始。所以基本上它看起来像这样:
|ID | group | row_number |
|---|-------|------------|
| 1 | Banana| 1 |
| 2 | Apple | 1 |
| 3 | Apple | 2 |
| 4 | Apple | 3 |
| 5 | Banana| 2 |
| 6 | Banana| 3 |
| 7 | Apple | 4 |
| 8 | Apple | 5 |
什么时候应该是这样:
|ID | group | row_number |
|---|-------|------------|
| 1 | Banana| 1 |
| 2 | Apple | 1 |
| 3 | Apple | 2 |
| 4 | Apple | 3 |
| 5 | Banana| 1 |
| 6 | Banana| 2 |
| 7 | Apple | 1 |
| 8 | Apple | 2 |
我不得不提的是,我有很多观察,而不仅仅是Apple和Banana这两组。因此,不幸的是,我必须将组命名为“Apple”和“Banana”之类的代码没有帮助。我试图解决这样的问题:
df1<- df1%>%
group_by(group) %>%
mutate(numbering = row_number())
但是这里的错误很明显。我也试图解决这个问题,但这非常困难。如果有人有解决方案,我将不胜感激!
解决方法
另一种方式:
df %>%
mutate(Temp=data.table::rleid(group)) %>%
group_by(Temp) %>%
mutate(row_number=row_number()) %>%
select(-Temp)
,
这里有 3 种方法可以做到这一点 -
基础 R -
df <- transform(df,row_number = ave(ID,with(rle(group),rep(seq_along(values),lengths)),FUN = seq_along))
df
# ID group row_number
#1 1 Banana 1
#2 2 Apple 1
#3 3 Apple 2
#4 4 Apple 3
#5 5 Banana 1
#6 6 Banana 2
#7 7 Apple 1
#8 8 Apple 2
dplyr
-
library(dplyr)
df %>%
group_by(grp = cumsum(group != lag(group,default = first(group)))) %>%
mutate(row_number = row_number()) %>%
ungroup %>%
select(-grp)
data.table
-
library(data.table)
setDT(df)[,row_number := seq_len(.N),rleid(group)]
数据
df <- structure(list(ID = 1:8,group = c("Banana","Apple","Banana","Apple")),row.names = c(NA,-8L),class = "data.frame")