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我如何只为 0 到 255 之间的数字编写正则表达式语句?0 和 255 将对该语句有效。

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4 回答 4

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您可以在此处找到一些数字范围:

http://www.regular-expressions.info/numericranges.html

你的例子是:

^([01]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])$ 
于 2012-05-21T09:36:35.820 回答
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^([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])$

这个工具对这些事情很有帮助。一点点搜索也不会伤害任何人。

但是,如果您想允许前导零,则需要调整模式。例如:

^([01][0-9][0-9]|2[0-4][0-9]|25[0-5])$
于 2012-05-21T09:35:40.127 回答
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尝试消极看待背后:

(?<!\-)\b0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])\b

解释

<!--
(?<!\-)\b0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])\b

Options: ^ and $ match at line breaks

Assert that it is impossible to match the regex below with the match ending at this position (negative lookbehind) «(?<!\-)»
   Match the character “-” literally «\-»
Assert position at a word boundary «\b»
Match the character “0” literally «0*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
Match the regular expression below and capture its match into backreference number 1 «([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])»
   Match either the regular expression below (attempting the next alternative only if this one fails) «[0-9]{1,2}»
      Match a single character in the range between “0” and “9” «[0-9]{1,2}»
         Between one and 2 times, as many times as possible, giving back as needed (greedy) «{1,2}»
   Or match regular expression number 2 below (attempting the next alternative only if this one fails) «1[0-9]{2}»
      Match the character “1” literally «1»
      Match a single character in the range between “0” and “9” «[0-9]{2}»
         Exactly 2 times «{2}»
   Or match regular expression number 3 below (attempting the next alternative only if this one fails) «2[0-4][0-9]»
      Match the character “2” literally «2»
      Match a single character in the range between “0” and “4” «[0-4]»
      Match a single character in the range between “0” and “9” «[0-9]»
   Or match regular expression number 4 below (the entire group fails if this one fails to match) «25[0-5]»
      Match the characters “25” literally «25»
      Match a single character in the range between “0” and “5” «[0-5]»
Assert position at a word boundary «\b»
-->
于 2012-05-21T09:53:53.767 回答
0

尝试

([01]?\d\d?|2[0-4]\d|25[0-5])
于 2012-05-21T09:37:32.940 回答