我可以使用什么正则表达式来验证0到255之间的数字? [英] What regex can I use to validate a number between 0 and 255?

问题描述

我想验证0-255之间的数字

I want to validate number in range of 0-255

我有这个表情

'/^([0-1]?[0-9]?[0-9])|([2][0-4][0-9])|(25[0-5])$/'

但这可以接受任何数字... 这可行:

But this accepts any number... And this works:

'/(^[0-1]?[0-9]?[0-9]$)|(^[2][0-4][0-9]$)|(^25[0-5]$)/'

为什么每个选项都必须有^和$?

why do I have to have ^ and $ for each option?

我知道了，但是我不能回答我的问题，所以-^和$的优先级高于|，因此/^(...)$/有帮助

edit: I have it, but I cannot answer my question, so - ^ and $ have higher priority than |, so /^(...)$/ helped

推荐答案

注意:

Note: @alex's answer is the way to go. Validating a number range with regex is like using a jackhammer to catch a fly.

但是，尽管如此，我还是想为这个问题"提供一个解释.

But nevertheless I wanted to provide an explanation for this "problem".

您不必这样做，只需将其正确分组即可，这意味着您必须将变更分组:

You don't have to, you just have to group it correctly, which means you have to group the alternation:

'/^(([0-1]?[0-9]?[0-9])|([2][0-4][0-9])|(25[0-5]))$/'
// ^                                             ^

否则，该表达式将被解释如下(逻辑上)

Otherwise the expression will be interpreted as follows (logically)

(^number) OR (number) OR (number$)

带有括号的将是

^(number OR number OR number)$

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