is_finite
(PHP 4 >= 4.2.0, PHP 5)
is_finite — Finds whether a value is a legal finite number
Описание
bool is_finite
( float $val
)
Checks whether val is a legal finite on this platform.
Список параметров
- val
-
The value to check
Возвращаемые значения
TRUE if val is a legal finite number within the allowed range for a PHP float on this platform, else FALSE.
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Коментарии
(is_finite($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
?>