not a number
In a computer, not a number (usually abbreviated NaN) indicates that an arithmetical operation has resulted in a value that is not a number understood (or representable) by the computer. Division by zero is one frequent cause of a result being NaN. Asking for the square root
of a negative number is another operation that can result in NaN (unless the computer has been programmed to recognize imaginary numbers
).
NaN is not a specific value that can be tested for with the usual comparison operators. The programmer is advised to test for NaN with a special function provided by the programming language (such as isNaN(x) in JavaScript.
Generally, computer algebra systems do not report NaN results even if they do display an error message for a given operation.
References
- 1 David Flanagan, JavaScript the Definitive Guide: The Definitive Guide. New York: O’Reilly (2006): 24
| Title | not a number |
|---|---|
| Canonical name | NotANumber |
| Date of creation | 2013-03-22 18:14:09 |
| Last modified on | 2013-03-22 18:14:09 |
| Owner | PrimeFan (13766) |
| Last modified by | PrimeFan (13766) |
| Numerical id | 4 |
| Author | PrimeFan (13766) |
| Entry type | Definition |
| Classification | msc 68P01 |