abs
(PHP 4, PHP 5)
abs — 绝对值
说明
$number
)
返回参数 number 的绝对值。
参数
-
number -
要处理的数字值
返回值
number 的绝对值。 如果参数 number
是 float ，则返回的类型也是 float ，否则返回
integer （因为 float 通常比 integer 有更大的取值范围）。
范例
Example #1 abs() 例子
<?php
$abs = abs (- 4.2 ); // $abs = 4.2; (double/float)
$abs2 = abs ( 5 ); // $abs2 = 5; (integer)
$abs3 = abs (- 5 ); // $abs3 = 5; (integer)
?> 参见
- gmp_abs() - Absolute value
- gmp_sign() - Sign of number
用户评论:
[#1] alex.khimich.org [2013-10-17 07:58:22]
Few ways to convert values to negative
<?php
// Multiplying by "-1"
$v = -1 * abs($v);
// Using ternary operator
$v = $v <= 0 ? $v : -$v;
?>
[#2] svein dot tjonndal at gmail dot com [2011-05-25 12:44:12]
If you don't have/want GMP and are working with large numbers/currencies:
<?php
function mb_abs($number)
{
return str_replace('-','',$number);
}
?>
No need to worry about encoding, as your numbers should all be basic (ANSI) strings.
[#3] Ister [2008-07-17 01:59:19]
[*EDIT* by danbrown AT php DOT net: Merged user's corrected code with previous post content.]
jeremys indicated one thing - there is no sgn function wich actually seems a bit strange for me. Of course it is as simple as possible, but it is usefull and it is a standard math function needed occasionally.
Well, I have solved this function in a bit different matter:
<?php
function sgn($liczba)
{
if($liczba>0)
$liczba=1;
else if($liczba<0)
$liczba=-1;
else if(!is_numeric($liczba))
$liczba=null;
else
$liczba=0;
return $liczba;
}
?>
The difference is that it returns null when the argument isn't a number at all.