如何在组内创建唯一的 ID 列，因为其他列中的变量正在更改

Question

我无法找到在以下问题中使用的正确代码：

我有一个数据集（df），其中每个 ROV 横断面有部分（行）。我想根据部分以及变量 Year 和 ROV 创建一个新的 ID 列（即新的分组变量）。我希望它包含前 5 个部分（行），然后是接下来的 5 个部分，依此类推 - 直到基材或 ROV 发生变化。所以并不是每个新 ID 都会由 5 个元素组成。

dataframe <- data.frame(
Year = c("2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2023","2023","2023"),
ROV=c("2","2","2","2","2","2","2","2","4","4","4","4","4","4","4","4"),
Section=c("3","4","5","6","7","8","9","10","1","2","3","4","5","6","7","8"),
Substrate=c("Mud","Mud","Mud","Mud","Mud","Mud","Mud","Mud","Bedrock","Bedrock","Bedrock","Bedrock","Dead Lophelia", "Dead Lophelia", "Bedrock","Bedrock"))
                        
result <- data.frame(Year = c("2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2021","2023","2023","2023"), 
ROV=c("2","2","2","2","2","2","2","2","4","4","4","4","4","4","4","4"),
Section = c("3","4","5","6","7","8","9","10","1","2","3","4","5","6","7","8"),
Substrate= c("Mud","Mud","Mud","Mud","Mud","Mud","Mud","Mud","Bedrock","Bedrock","Bedrock","Bedrock","Dead Lophelia", "Dead Lophelia", "Bedrock","Bedrock"),
ID=c("1","1","1","1","1","2","2","2","3","3","3","3","4","6","7","7" ))

此代码每 5 行（=部分）创建一个 ID，但不处理 ROV 或 Substrate 中的更改。我已经尝试过 slice() 但没有得到所需的输出。有没有 dplyr 解决方案？

dataframe$ID <- 1 + seq(0, nrow(dataframe) - 1) %/% 5

Answer 1

这是一种使用

dplyr

的方法

library(dplyr)

dataframe %>%
  mutate(subgroup = rep(LETTERS, each = 5, length.out = n()),
                        .by = c(ROV, Substrate, Year)) %>%
  mutate(ID = cur_group_id(),
         .by = c(ROV, Substrate, Year, subgroup)) %>%
  select(-subgroup)
#>    Year ROV Section     Substrate ID
#> 1  2021   2       3           Mud  1
#> 2  2021   2       4           Mud  1
#> 3  2021   2       5           Mud  1
#> 4  2021   2       6           Mud  1
#> 5  2021   2       7           Mud  1
#> 6  2021   2       8           Mud  2
#> 7  2021   2       9           Mud  2
#> 8  2021   2      10           Mud  2
#> 9  2021   4       1       Bedrock  3
#> 10 2021   4       2       Bedrock  3
#> 11 2021   4       3       Bedrock  3
#> 12 2021   4       4       Bedrock  3
#> 13 2021   4       5 Dead Lophelia  4
#> 14 2023   4       6 Dead Lophelia  5
#> 15 2023   4       7       Bedrock  6
#> 16 2023   4       8       Bedrock  6

^{创建于 2024-01-09，使用 reprex v2.0.2}