Remove constant terms from formula. Also remove categorical variables with a max of one example per category
Usage
removeConstantTerms(formula, data)
Arguments
- formula
original formula
- data
data.frame
Value
a formula, possibly with terms omitted.
Details
Adapted from MoEClust::drop_constants
Examples
# Valid formula
removeConstantTerms(~ group + extra, sleep)
#> ~group + extra
#> <environment: 0x3083db4a0>
# there is no variation in 'group' in this dataset
removeConstantTerms(~ group + extra, sleep[1:3, ])
#> ~1 + extra
#> <environment: 0x3083db4a0>
