php或js或其他脚本语言中如何实现百分比转换成小数

RT，比如25%，如何转换成0.25？

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要支持 25%, 2%, 2.01%, 25.00%

d:\>perl -e "$_='2%'; s/([1-9]\d)(?:.(\d+))?%/0.\1\2/g; s/(\d)(?:.(\d+))?%/0.0\1\2/g; print"
0.02

d:\>perl -e "$_='25%'; s/([1-9]\d)(?:.(\d+))?%/0.\1\2/g; s/(\d)(?:.(\d+))?%/0.0\1\2/g; print"
0.25

d:\>perl -e "$_='2.01%'; s/([1-9]\d)(?:.(\d+))?%/0.\1\2/g; s/(\d)(?:.(\d+))?%/0.0\1\2/g; print"
0.0201

d:\>perl -e "$_='25.00%'; s/([1-9]\d)(?:.(\d+))?%/0.\1\2/g; s/(\d)(?:.(\d+))?%/0.0\1\2/g; print"
0.2500

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上面主要是练练正则, perl里这么写也可以了.

d:\>perl -e "$x='25.08%'; print $x/100"
0.2508

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coffeescript:

x=(x)->Number(x.replace '%','')/100

编译成js:

var x;

x = function(x) {
  return Number(x.replace('%', '')) / 100;
};

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echo intval('25%') / 100;

这个答案有问题，所以更新成下面这个：

echo ('25.85%') * 1;

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最近用了一阵精度计算，大概写写提供个思路，没测

$num = "25%";
bcscale(strpos($num,'.') === false ? 2 : ( strlen($num) - strpos($num,'.') + 1));
$num = bcdiv(str_replace('%','',$num) ,100);

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PHP版
$a="25%"; $a=str_replace('%','',$a);//去百分号 echo is_numeric($a)?$a/100:'呀不是数字!';

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PHP版本：http://3v4l.org/RgYnN

JavaScript版本：
http://jsfiddle.net/lizheming/ncfq6fdk/1/

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python：

>>> def percent2decimal(x):
...     return float(x.strip('%'))/100
...
>>> percent2decimal("25%")
0.25
>>> percent2decimal("250%")
2.5