I want custom row numbers such that if consecutive As or Bs appear but not Cs then the same ID will be repeated something like below:
Required
<code> X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 6
10 B 7
</code>
<code> X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 6
10 B 7
</code>
X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 6
10 B 7
Attempted
<code>library(tidyverse)
df1 <-
data.frame(X = c("A", "B", "A", "A", "B", "B", "B", "C", "C", "B"))
df1 %>%
mutate(ID = row_number())
#> X ID
#> 1 A 1
#> 2 B 2
#> 3 A 3
#> 4 A 4
#> 5 B 5
#> 6 B 6
#> 7 B 7
#> 8 C 8
#> 9 C 9
#> 10 B 10
</code>
<code>library(tidyverse)
df1 <-
data.frame(X = c("A", "B", "A", "A", "B", "B", "B", "C", "C", "B"))
df1 %>%
mutate(ID = row_number())
#> X ID
#> 1 A 1
#> 2 B 2
#> 3 A 3
#> 4 A 4
#> 5 B 5
#> 6 B 6
#> 7 B 7
#> 8 C 8
#> 9 C 9
#> 10 B 10
</code>
library(tidyverse)
df1 <-
data.frame(X = c("A", "B", "A", "A", "B", "B", "B", "C", "C", "B"))
df1 %>%
mutate(ID = row_number())
#> X ID
#> 1 A 1
#> 2 B 2
#> 3 A 3
#> 4 A 4
#> 5 B 5
#> 6 B 6
#> 7 B 7
#> 8 C 8
#> 9 C 9
#> 10 B 10
1
Use rle.
<code>> transform(df1, ID=with(rle(X), rep(seq_along(values), lengths)))
X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 5
10 B 6
</code>
<code>> transform(df1, ID=with(rle(X), rep(seq_along(values), lengths)))
X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 5
10 B 6
</code>
> transform(df1, ID=with(rle(X), rep(seq_along(values), lengths)))
X ID
1 A 1
2 B 2
3 A 3
4 A 3
5 B 4
6 B 4
7 B 4
8 C 5
9 C 5
10 B 6
Note, that these are not “row numbers”.
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