我对正则表达式不太了解，希望有人可以给我一个有效的声明，并解释它是如何工作的，也许可以将我指向一个学习正则表达式的好网站。
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2 回答
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您发布的正则表达式的解释（使用RegexBuddy创建）：
^.syn ((([0-9]{1,3}\.){3}[0-9]{1,3})|([a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_.-]+)) [0-9]{1,5} [0-9]{1,15} [0-9]{1,15}
Assert position at the beginning of the string «^»
Match any single character that is not a line break character «.»
Match the characters “syn ” literally «syn »
Match the regular expression below and capture its match into backreference number 1 «((([0-9]{1,3}\.){3}[0-9]{1,3})|([a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_.-]+))»
Match either the regular expression below (attempting the next alternative only if this one fails) «(([0-9]{1,3}\.){3}[0-9]{1,3})»
Match the regular expression below and capture its match into backreference number 2 «(([0-9]{1,3}\.){3}[0-9]{1,3})»
Match the regular expression below and capture its match into backreference number 3 «([0-9]{1,3}\.){3}»
Exactly 3 times «{3}»
Note: You repeated the capturing group itself. The group will capture only the last iteration. Put a capturing group around the repeated group to capture all iterations. «{3}»
Match a single character in the range between “0” and “9” «[0-9]{1,3}»
Between one and 3 times, as many times as possible, giving back as needed (greedy) «{1,3}»
Match the character “.” literally «\.»
Match a single character in the range between “0” and “9” «[0-9]{1,3}»
Between one and 3 times, as many times as possible, giving back as needed (greedy) «{1,3}»
Or match regular expression number 2 below (the entire group fails if this one fails to match) «([a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_.-]+)»
Match the regular expression below and capture its match into backreference number 4 «([a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_.-]+)»
Match a single character present in the list below «[a-zA-Z0-9_-]+»
Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
A character in the range between “a” and “z” «a-z»
A character in the range between “A” and “Z” «A-Z»
A character in the range between “0” and “9” «0-9»
The character “_” «_»
The character “-” «-»
Match the character “.” literally «\.»
Match a single character present in the list below «[a-zA-Z0-9_-]+»
Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
A character in the range between “a” and “z” «a-z»
A character in the range between “A” and “Z” «A-Z»
A character in the range between “0” and “9” «0-9»
The character “_” «_»
The character “-” «-»
Match the character “.” literally «\.»
Match a single character present in the list below «[a-zA-Z0-9_.-]+»
Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
A character in the range between “a” and “z” «a-z»
A character in the range between “A” and “Z” «A-Z»
A character in the range between “0” and “9” «0-9»
The character “_” «_»
The character “.” «.»
The character “-” «-»
Match the character “ ” literally « »
Match a single character in the range between “0” and “9” «[0-9]{1,5}»
Between one and 5 times, as many times as possible, giving back as needed (greedy) «{1,5}»
Match the character “ ” literally « »
Match a single character in the range between “0” and “9” «[0-9]{1,15}»
Between one and 15 times, as many times as possible, giving back as needed (greedy) «{1,15}»
Match the character “ ” literally « »
Match a single character in the range between “0” and “9” «[0-9]{1,15}»
Between one and 15 times, as many times as possible, giving back as needed (greedy) «{1,15}»
于 2013-07-06T11:06:43.523 回答
0
^.syn ((([0-9]{1,3}\.){3}[0-9]{1,3})|([a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_.-]+)) [0-9]{1,5} [0-9]{1,15} [0-9]{1,15}
一些匹配上述正则表达式的示例文本：
jsyn 467.317.98.0 7259 04124798576 90058xsyn 3.5.0.545 952 7940 261348Tsyn 9.47.-.u 3 12 5
有用的网站
于 2013-07-06T06:47:56.247 回答