pub fn n_features(&self) -> usize {
        match self {
            Features::Dense(ref da) => da.len(),
            Features::Sparse(sa) => sa.dim,
        }
    }
/// Return the number of features.
Return the number of features.
Return the number of features .
pub fn n_features(&self) -> usize {
        match self {
            Features::Dense(ref da) => da.len(),
            Features::Sparse(sa) => sa.dim,
        }
    }
pub fn n_features ( & self ) -> usize { match self { Features :: Dense ( ref da ) => da . len ( ) , Features :: Sparse ( sa ) => sa . dim , } }
Return the number of features.
Return the number of features .
&self
&self