is_finite
(PHP 4 >= 4.2.0, PHP 5)
is_finite — Finds whether a value is a legal finite number
Description
bool is_finite
( float
$val
)
Checks whether val is a legal finite
on this platform.
Parameters
-
val -
The value to check
Return Values
TRUE if val is a legal finite
number within the allowed range for a PHP float on this platform,
else FALSE.
See Also
- is_infinite() - Finds whether a value is infinite
- is_nan() - Finds whether a value is not a number
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Коментарии
(is_finite($float)) is equivalent to (!is_infinite($float) && !is_nan($float)), i.e. a number can only be one of finite, infinite and NaN. You don't need to check both is_infinite() and is_nan() to see if a number is invalid or out of range.
<?php
$finite = 42;
$infinite = log(0);
$nan = acos(2);
var_dump(is_finite($finite), is_infinite($finite), is_nan($finite)); // true, false, false
var_dump(is_finite($infinite), is_infinite($infinite), is_nan($infinite)); // false, true, false
var_dump(is_finite($nan), is_infinite($nan), is_nan($nan)); // false, false, true
?>