R Programming By Example

Special values

There are a few special values in R. The NA values are used to represent missing values, which stands for not available. If a computation results in a number that is too big, R will return Inf for a positive number and -Inf for a negative number, meaning positive and negative infinity, respectively. These are also returned when a number is divided by 0. Sometimes a computation will produce a result that makes little sense. In these cases, we will get a NaN, which stands for not a number. And, finally, there is a null object, represented by NULL. The symbol NULL always points to the same object (which is a data type on its own) and is often used as a default argument in functions to mean that no value was passed through. You ...