Add predictors to a formula

This merges a one- or two-sided formula f with the right-hand sides of all formulas supplied in ....

Usage

add_predictors(f, ..., fun = "+")

Arguments

f

A formula.

...

Formulas whose right-hand sides will be merged to f.

fun

A function name indicating how to merge the right-hand sides.

Examples

f <- lhs ~ rhs
add_predictors(f, ~var1, ~var2)
#> lhs ~ rhs + var1 + var2
#> <environment: 0x55fd8f9ba748>

# Left-hand sides are ignored:
add_predictors(f, lhs1 ~ var1, lhs2 ~ var2)
#> lhs ~ rhs + var1 + var2
#> <environment: 0x55fd8f9ba748>

# fun can also be set to a function like "*":
add_predictors(f, ~var1, ~var2, fun = "*")
#> lhs ~ rhs * var1 * var2
#> <environment: 0x55fd8f9ba748>