PHP is_nan() Function
Example
Check whether a value is 'not-a-number':
<?php
echo is_nan(200) . "<br>";
echo is_nan(acos(1.01));
?>
Run example »
Definition and Usage
The is_nan() function checks whether a value is 'not a number'.
This function returns true (1) if the specified value is 'not a number', otherwise it returns false/nothing.
Syntax
is_nan(value);
| Parameter | Description |
|---|---|
| value | Required. Specifies the value to check |
Technical Details
| Return Value: | TRUE if value is 'not a number', FALSE otherwise |
|---|---|
| Return Type: | Boolean |
| PHP Version: | 4.2+ |
PHP Math Reference
