I need to subset either the last one or two digits (replicates) of a coding variable (v1), that goes from 1 to 12. With the str_sub function, I cannot get the whole number when there are two digits. If I choose the last two digits, then the function gets the preceeding letter in one-digit replicates:
v1<-c("D018BG1","D018BG2","D018BG3","D018BG4","D018BG5","D018BG6","D018BG7","D018BG8","D018BG9",
"D018BG10","D018BG11","D018BG12")
df<-data.frame(v1)
df
v1
1 D018BG1
2 D018BG2
3 D018BG3
4 D018BG4
5 D018BG5
6 D018BG6
7 D018BG7
8 D018BG8
9 D018BG9
10 D018BG10
11 D018BG11
12 D018BG12
df%>%
mutate(replicate=str_sub(v1,-1,-1))
v1 replicate
1 D018BG1 1
2 D018BG2 2
3 D018BG3 3
4 D018BG4 4
5 D018BG5 5
6 D018BG6 6
7 D018BG7 7
8 D018BG8 8
9 D018BG9 9
10 D018BG10 0
11 D018BG11 1
12 D018BG12 2
df%>%
mutate(replicate=str_sub(v1,-2,-1))
v1 replicate
1 D018BG1 G1
2 D018BG2 G2
3 D018BG3 G3
4 D018BG4 G4
5 D018BG5 G5
6 D018BG6 G6
7 D018BG7 G7
8 D018BG8 G8
9 D018BG9 G9
10 D018BG10 10
11 D018BG11 11
12 D018BG12 12
How can this be done?
Thanks in advance!
You can use the str_extract function from {stringr}.
library(dplyr)
library(stringr)
df %>%
mutate(replicate_one_digit = as.numeric(str_extract(v1, "\\d$")),
replicate_two_digits = as.numeric(str_extract(v1, "\\d{1,2}$")))
v1 replicate_one_digit replicate_two_digits
1 D018BG1 1 1
2 D018BG2 2 2
3 D018BG3 3 3
4 D018BG4 4 4
5 D018BG5 5 5
6 D018BG6 6 6
7 D018BG7 7 7
8 D018BG8 8 8
9 D018BG9 9 9
10 D018BG10 0 10
11 D018BG11 1 11
12 D018BG12 2 12