Determine whether a value is non-numeric:
<?phpecho is_nan(200) . "<br>";echo is_nan(acos(1.01));?>The is_nan() function determines whether a value is non-numeric.
If the specified value is non-numeric, the function returns true (1). Otherwise, it returns false/nothing.
is_nan( value );
| parameter | describe |
|---|---|
| value | Required. Specifies the value to be checked. |
| Return value: | Returns TRUE if value is non-numeric. Otherwise, returns FALSE. |
|---|---|
| Return type: | Boolean |
| PHP version: | 4.2+ |