Converting R formula to string and then manipulating it-CodePudding

exposure <- 'B'
outcome <- 'A'

I have a formula that looks like this in R

form <- formula(A ~ B   C   D)

I want to convert it to a string like this where I remove the exposure and the outcome

C   D

How can i do this in R?

CodePudding user response：

Perhaps this helps

reformulate(setdiff(all.vars(form), c(exposure, outcome)))
~C   D

CodePudding user response：

form_str <- as.character(form)
[1] "~"         "A"         "B   C   D"
variables <- strsplit(form_str[3], "   ", fixed = TRUE)[[1]]
[1] "B" "C" "D"
paste(setdiff(variables, exposure), collapse = "   ")
"C   D"