正则表达式可以匹配任何数字(实数，有理数和符号) [英] Regex to match any number (Real, rational along with signs)

问题描述

我写了一个正则表达式来匹配任何数字:

I've written a regex to match any number:

• 正面和负面
• 十进制
• 实数

以下正则表达式效果很好，但有一个缺点

The following regex does well but there's one drawback

([\+\-]{1}){0,1}?[\d]*(\.{1})?[\\d]*

对于诸如 + 或-之类的输入，这也是肯定的.任何指针将不胜感激.谢谢.

It is positive for inputs such as + or - as well. Any pointers will be greatly appreciated. Thanks.

正则表达式应与以下输入配合使用

The regex should work with the following inputs

5，+5，-5，0.5，+0.5，-0.5，.5，+.5，-.5

5, +5, -5, 0.5, +0.5, -0.5, .5, +.5, -.5

并且不应与以下输入内容匹配

and shouldn't match the following inputs

+

-

+.

-.

.

这是tchrist的回答，很完美.

(?:(?i)(?:[+-]?)(?:(?=[.]?[0-9])(?:[0-9]*)(?:(?:[.])(?:[0-9]{0,}))?)(?:(?:[E])(?:(?:[+-]?)(?:[0-9]+))|))

推荐答案

如果您想要看起来像C浮点数的方法，则可以使用

If you want something that looks like a C float, here’s how to tickle Perl into coughing out a regex that does that, using the Regexp::Common module from CPAN:

$ perl -MRegexp::Common -le 'print $RE{num}{real}'
(?:(?i)(?:[+-]?)(?:(?=[.]?[0123456789])(?:[0123456789]*)(?:(?:[.])(?:[0123456789]{0,}))?)(?:(?:[E])(?:(?:[+-]?)(?:[0123456789]+))|))

您可以根据需要进行一些调整，但这可以为您提供基本的思想.

You can tune that a bit if you want, but that gives you the basic idea.

它确实非常灵活.例如，这为以2为底的实数倒出了一个模式，即允许每三个位置使用逗号:

It’s really remarkably flexible. For example, this spits out a pattern for base-2 real numbers taht allow commas every three places:

$ perl -MRegexp::Common -le 'print $RE{num}{real}{-base => 2}{-sep => ","}{-group => 3}'
(?:(?i)(?:[+-]?)(?:(?=[.]?[01])(?:[01]{1,3}(?:(?:[,])[01]{3})*)(?:(?:[.])(?:[01]{0,}))?)(?:(?:[E])(?:(?:[+-]?)(?:[01]+))|))

文档显示，可以为您吐出的数字模式是:

The documentation shows that the full possible syntax for the numeric patterns it can spit out for you is:

$RE{num}{int}{-base}{-sep}{-group}{-places} 
$RE{num}{real}{-base}{-radix}{-places}{-sep}{-group}{-expon} 
$RE{num}{dec}{-radix}{-places}{-sep}{-group}{-expon} 
$RE{num}{oct}{-radix}{-places}{-sep}{-group}{-expon} 
$RE{num}{bin}{-radix}{-places}{-sep}{-group}{-expon} 
$RE{num}{hex}{-radix}{-places}{-sep}{-group}{-expon} 
$RE{num}{decimal}{-base}{-radix}{-places}{-sep}{-group} 
$RE{num}{square} 
$RE{num}{roman}

使它真正针对您想要的内容进行自定义.是的，您当然可以在Java中使用这些模式.

Making it really to customize it for whatever you want. And yes, of course you can use these patterns in Java.

享受.

这篇关于正则表达式可以匹配任何数字(实数，有理数和符号)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！