php 绝对值

<?php
$abs = abs(-4.2); // $abs = 4.2;(double/float)
$abs2 = abs(5); // $abs2 = 5;(integer)
$abs3 = abs(-5); // $abs3 = 5;(integer)
?>

 

<?php
$flag = 1;// either 0 or1
$flag = abs($flag - 1);
?>