recoding based on two condtions in r - r

Question

I have an example dataset looks like:
data <- as.data.frame(c("A","B","C","X1_theta","X2_theta","AB_theta","BC_theta","CD_theta"))
colnames(data) <- "category"
> data
category
1 A
2 B
3 C
4 X1_theta
5 X2_theta
6 AB_theta
7 BC_theta
8 CD_theta
I am trying to generate a logical variable when the category (variable) contains "theta" in it. However, I would like to assign the logical value as "FALSE" when cell values contain "X1" and "X2".
Here is what I did:
data$logic <- str_detect(data$category, "theta")
> data
category logic
1 A FALSE
2 B FALSE
3 C FALSE
4 X1_theta TRUE
5 X2_theta TRUE
6 AB_theta TRUE
7 BC_theta TRUE
8 CD_theta TRUE
here, all cells value that have "theta" have the logical value of "TRUE".
Then, I wrote this below to just assign "FALSE" when the cell value has "X" in it.
data$logic <- ifelse(grepl("X", data$category), "FALSE", "TRUE")
> data
category logic
1 A TRUE
2 B TRUE
3 C TRUE
4 X1_theta FALSE
5 X2_theta FALSE
6 AB_theta TRUE
7 BC_theta TRUE
8 CD_theta TRUE
But this, of course, overwrote the previous application
What I would like to get is to combine two conditions:
> data
category logic
1 A FALSE
2 B FALSE
3 C FALSE
4 X1_theta FALSE
5 X2_theta FALSE
6 AB_theta TRUE
7 BC_theta TRUE
8 CD_theta TRUE
Any thoughts?
Thanks

Answer 1

We can create the 'logic', by detecting substring 'theta' at the end and not having 'X' ([^X]) as the starting (^) character
libary(dplyr)
library(stringr)
library(tidyr)
data %>%
mutate(logic = str_detect(category, "^[^X].*theta$"))
If we need to split the column into separate columns based on the conditions
data %>%
mutate(logic = str_detect(category, "^[^X].*theta$"),
category = case_when(logic ~ str_replace(category, "_", ","),
TRUE ~ as.character(category))) %>%
separate(category, into = c("split1", "split2"), sep= ",", remove = FALSE)
# category split1 split2 logic
#1 A A <NA> FALSE
#2 B B <NA> FALSE
#3 C C <NA> FALSE
#4 X1_theta X1_theta <NA> FALSE
#5 X2_theta X2_theta <NA> FALSE
#6 AB,theta AB theta TRUE
#7 BC,theta BC theta TRUE
#8 CD,theta CD theta TRUE
Or in base R
data$logic <- with(data, grepl("^[^X].*theta$", category))
Another option is to have two grepl condition statements
data$logic <- with(data, grepl("theta$", category) & !grepl("^X\\d+", category))
data$logic
#[1] FALSE FALSE FALSE FALSE FALSE TRUE TRUE TRUE

Answer 2

Not the cleanest in the world (since it adds 2 unnecessary cols) but it gets the job done:
data <- as.data.frame(c("A","B","C","X1_theta","X2_theta","AB_theta","BC_theta","CD_theta"))
colnames(data) <- "category"
data$logic1 <- ifelse(grepl('X',data$category), FALSE, TRUE)
data$logic2 <- ifelse(grepl('theta',data$category),TRUE, FALSE)
data$logic <- ifelse((data$logic1 == TRUE & data$logic2 == TRUE), TRUE, FALSE)
print(data)
I think you can also remove the logic1 and logic2 cols if you want but I usually don't bother (I'm a messy coder haha).
Hope this helped!
EDIT: akrun's grepl solution does what I'm doing way more cleanly (as in, it doesn't require the extra cols). I definitely recommend that approach!