estimation.formula.factor_interaction.factor_interaction

estimation.formula.factor_interaction.factor_interaction(
    data,
    var2=None,
    *,
    ref=None,
    ref2=None,
    bin=None,
    bin2=None,
)

Fixest-style i() operator for categorical encoding with interactions.

Args: data: The categorical variable var2: Optional second variable for interaction (continuous or categorical) ref: Reference level to drop from data ref2: Reference level to drop from var2 (if categorical) bin: Dict mapping new_level -> [old_levels] for binning

Naming convention (matches R fixest): i(cyl) -> cyl::4, cyl::6, cyl::8 i(cyl, ref=4) -> cyl::6, cyl::8 i(cyl, wt) -> cyl::4:wt, cyl::6:wt, cyl::8:wt i(cyl, wt, ref=4) -> cyl::6:wt, cyl::8:wt