Returns data of the data frame as a 2D array. The method attempts to convert all values to the specified type 'R. If the specified type is 'float' or 'double' then the method automatically uses NaN. For other values, the default value has to be explicitly specified using another overload. [category:Fancy accessors]

Returns data of the data frame as a 2D array. The method attempts to convert all values to the specified type 'R. When a value is missing, the specified `defaultValue` is used. ## Parameters - `defaultValue` - Default value used to fill all missing values [category:Fancy accessors]