Function builtin_as_matrix 

fn builtin_as_matrix(
    args: &[RValue],
    _: &[(String, RValue)],
) -> Result<RValue, RError>

Coerce an object to a matrix.

For vectors, creates a single-column matrix. For data frames, converts all columns to a common type and combines into a matrix.

@param x object to coerce @return matrix (vector with dim attribute) @namespace base