is_nan
(PHP 4 >= 4.2.0, PHP 5)
is_nan — Finds whether a value is not a number
Description
bool is_nan
( float
$val
)
Checks whether val is 'not a number',
like the result of acos(1.01).
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Parameters
-
val -
The value to check
Return Values
Returns TRUE if val is 'not a number',
else FALSE.
Examples
Example #1 is_nan() example
<?php
// Invalid calculation, will return a
// NaN value
$nan = acos(8);
var_dump($nan, is_nan($nan));
?>
The above example will output:
float(NAN) bool(true)
See Also
- is_finite() - Finds whether a value is a legal finite number
- is_infinite() - Finds whether a value is infinite
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