在纵向数据中到达某个类别后，下降因子级别

Question

我有一个数据框架的记录数据，一个纵向结构如下：

 id          event
1   1   registration
2   1     inspection
3   1     inspection
4   1 deregistration
5   2   registration
6   2     inspection
7   2 deregistration
8   2     inspection
9   3   registration
10  3 deregistration
11  3     inspection
12  3     inspection
13  4   registration
14  4     inspection
15  4     inspection
16  4 deregistration

我需要降低一个类别之后的水平。本质上，我需要删除event在类别deregistration之后的后续级别。数据框架应该如下所示：

   id          event
1   1   registration
2   1     inspection
3   1     inspection
4   1 deregistration
5   2   registration
6   2     inspection
7   2 deregistration
8   3   registration
9   3 deregistration
10  4   registration
11  4     inspection
12  4     inspection
13  4 deregistration 

这是生成df的de

df = data.frame(id = rep(1:4, each = 4), 
                  event = as.factor(c("registration", "inspection", "inspection", "deregistration",
                                  "registration", "inspection", "deregistration", "inspection",
                                  "registration", "deregistration","inspection", "inspection",
                                  "registration", "inspection", "inspection", "deregistration")))

Answer 1

使用dplyr和tidyr的解决方案。df2是最后的输出。

library(dplyr)
library(tidyr)

df2 <- df %>% 
  group_by(id) %>%
  mutate(Deregistration = ifelse(event == "deregistration", 1, NA)) %>%
  fill(Deregistration, .direction = "up") %>%
  drop_na(Deregistration) %>%
  select(-Deregistration)

df2
# A tibble: 13 x 2
# Groups:   id [4]
      id          event
   <int>         <fctr>
 1     1   registration
 2     1     inspection
 3     1     inspection
 4     1 deregistration
 5     2   registration
 6     2     inspection
 7     2 deregistration
 8     3   registration
 9     3 deregistration
10     4   registration
11     4     inspection
12     4     inspection
13     4 deregistration