create a formula of the form leftterm ~ rightterms[1] + rightterms[2] +
...
Usage
toFormula(leftterm, rightterms, as.formula = TRUE)
Arguments
- leftterm
character. Left term of the formula
- rightterms
vector of character. Right terms of the formula to be
concatenated with "+".
- as.formula
if TRUE (default) the formula object is returned, otherwise
the formula string (character)
Value
formula object as generated by formula or formula string
(character) of the form leftterm ~ rightterms[1] +
rightterms[2] + ... if as.formula is FALSE
Examples
f1 <- toFormula("y", c("x1", "x2"))
f2 <- toFormula("y", paste0("x", 1:20))
f3 <- toFormula("BMI", c("height", "mass"), as.formula = FALSE)
# f1 and f2 are formulas ...
class(f1)
#> [1] "formula"
class(f2)
#> [1] "formula"
# ... but f3 is just "character"
class(f3)
#> [1] "character"