I am trying to update a formula for a linear model in R, based on names of variables that I have stored in an array. I am using substitute() for that and the code is as follows.
var = 'a'
covar = c('b', 'c')
covar = paste(c(var, covar), collapse = ' + ')
formula = substitute(condition ~ (1|subject) + v, list(v = as.name(covar)))
print(formula)
Output
condition ~ (1 | subject) + `a + b + c`
How do I remove the extra `` around a + b + c?
If I don't concatenate with paste, then it works, but I need those extra variables...
var = 'a'
formula = substitute(condition ~ (1|subject) + v, list(v = as.name(var)))
print(formula)
Output
condition ~ (1 | subject) + a
Both var and covar are char type.
Another solution that lets iteratively change v in formula that could also work
Maybe I misunderstood what you are doing, but the following seems to work:
form <- 'condition ~ (1|subject) + v'
var <- 'a'
covar <- c('b', 'c')
Then combine with paste and turn to formula directly:
covar <- paste(var, paste(covar, collapse=" + "), sep=" + ")
form <- formula(paste(form, covar, sep=" + "))
Output:
condition ~ (1 | subject) + v + a + b + c