Formula, ModelFrame and ModelMatrix types
In R, the functions for fitting statistical models based on a linear predictor usually allow for a formula/data specification of the model. The data part is a
data.frame object in
R. In Julia the corresponding type is a
DataFrame as implemented in the DataFrames package.
A formula object in
R is an expression whose top-level operator is a unary or binary tilde,
~. The interpretation of many operators, including
: are overridden in the formula language. See the result of
R for the details.