From an initial model formula, create a list of formulas that exclude each predictor.
Arguments
- formula
A model formula that contains at least two predictors.
- data
A data frame.
- full_model
A logical; should the list include the original formula?
- ...
Options to pass to
stats::model.frame()
Details
The new formulas obey the hierarchy rule so that interactions without main effects are not included (unless the original formula contains such terms).
Factor predictors are left as-is (i.e., no indicator variables are created).
Examples
data(penguins, package = "modeldata")
leave_var_out_formulas(
bill_length_mm ~ .,
data = penguins
)
#> $species
#> bill_length_mm ~ island + bill_depth_mm + flipper_length_mm +
#> body_mass_g + sex
#> <environment: base>
#>
#> $island
#> bill_length_mm ~ species + bill_depth_mm + flipper_length_mm +
#> body_mass_g + sex
#> <environment: base>
#>
#> $bill_depth_mm
#> bill_length_mm ~ species + island + flipper_length_mm + body_mass_g +
#> sex
#> <environment: base>
#>
#> $flipper_length_mm
#> bill_length_mm ~ species + island + bill_depth_mm + body_mass_g +
#> sex
#> <environment: base>
#>
#> $body_mass_g
#> bill_length_mm ~ species + island + bill_depth_mm + flipper_length_mm +
#> sex
#> <environment: base>
#>
#> $sex
#> bill_length_mm ~ species + island + bill_depth_mm + flipper_length_mm +
#> body_mass_g
#> <environment: base>
#>
#> $everything
#> bill_length_mm ~ .
#> <environment: 0x561af5142ad0>
#>
leave_var_out_formulas(
bill_length_mm ~ (island + sex)^2 + flipper_length_mm,
data = penguins
)
#> $island
#> bill_length_mm ~ sex + flipper_length_mm
#> <environment: base>
#>
#> $sex
#> bill_length_mm ~ island + flipper_length_mm
#> <environment: base>
#>
#> $flipper_length_mm
#> bill_length_mm ~ island + sex + island:sex
#> <environment: base>
#>
#> $`island:sex`
#> bill_length_mm ~ island + sex + flipper_length_mm
#> <environment: base>
#>
#> $everything
#> bill_length_mm ~ (island + sex)^2 + flipper_length_mm
#> <environment: 0x561af5142ad0>
#>
leave_var_out_formulas(
bill_length_mm ~ (island + sex)^2 + flipper_length_mm +
I(flipper_length_mm^2),
data = penguins
)
#> $island
#> bill_length_mm ~ sex + flipper_length_mm + I(flipper_length_mm^2)
#> <environment: base>
#>
#> $sex
#> bill_length_mm ~ island + flipper_length_mm + I(flipper_length_mm^2)
#> <environment: base>
#>
#> $flipper_length_mm
#> bill_length_mm ~ island + sex + island:sex
#> <environment: base>
#>
#> $`I(flipper_length_mm^2)`
#> bill_length_mm ~ island + sex + flipper_length_mm + island:sex
#> <environment: base>
#>
#> $`island:sex`
#> bill_length_mm ~ island + sex + flipper_length_mm + I(flipper_length_mm^2)
#> <environment: base>
#>
#> $everything
#> bill_length_mm ~ (island + sex)^2 + flipper_length_mm + I(flipper_length_mm^2)
#> <environment: 0x561af5142ad0>
#>