正则表达式只匹配到第一次出现类匹配 [英] Regex to match only till first occurence of class match

问题描述

我正在寻找构建一个正则表达式来帮助我识别匹配的第一次出现.

I'm looking to construct a regex which will help me identify the first occurrence of a match.

我当前的正则表达式是 "(.*)[Cc][Aa][Ss][Ee][^a-zA-Z\\d]*(\\d\\d*)[^a-zA-Z\\d]*(.*)"

My current regex is "(.*)[Cc][Aa][Ss][Ee][^a-zA-Z\\d]*(\\d\\d*)[^a-zA-Z\\d]*(.*)"

我想要做的是查找输入字符串是否包含单词case"(不区分大小写)，后跟任意数量的特殊字符，后跟一个数字；我想检索文本的 3 部分.假设我的输入字符串是 "RE: FW: case:-1234: there is some description"使用这个正则表达式，我可以检索，"RE: FW:", "1234", "there is some description".

What I am trying to do is to find if the input string contains the word "case" (case insensitive), followed by any number of special characters, followed by a number; I want to retrieve 3 parts of the text. Say my input string is "RE: FW: case:-1234: there is some description" Using this regex, I am able to retrieve, "RE: FW: ", "1234", "there is some description".

这很好，但如果我的输入字符串是RE:FW:case:-1234:这是关于案例789重新开放"然后我的正则表达式返回，"RE: FW: case:-1234: This is in reference to", "789", "reopening".

This is fine, but if my input string is "RE: FW: case:-1234: This is in reference to case 789 reopening" Then my regex returns, "RE: FW: case:-1234: This is in reference to", "789", "reopening".

我想得到的是"RE: FW:", "1234", "这是关于案例789重新开放".

What I would like to get is "RE: FW: ", "1234", "This is in reference to case 789 reopening".

我是正则表达式的新手，非常感谢您的帮助.

I am a newbie with regex, so any help is much appreciated.

注意:我正在开发基于 Java 的工具，因此与 Java 兼容的正则表达式会很好.

Note: I am working on a java based tool, so java compatible regex would be nice.

推荐答案

您的正则表达式是否必须匹配整个字符串(即它是否使用 matches)?如果不是(或者如果您可以选择使用 find 代替)，只需删除 (.*)，因为那是将您的匹配推回去的原因:

Does your regex have to match the entire string (i.e. does it use matches)? If not (or if you can choose to use find instead) simply remove the (.*), because that's what pushes your match back:

[Cc][Aa][Ss][Ee][^a-zA-Z\\d]*(\\d\\d*)[^a-zA-Z\\d]*

否则，使前导重复非贪婪；

Otherwise, make the leading repetition non-greedy;

(.*?)[Cc][Aa][Ss][Ee][^a-zA-Z\\d]*(\\d\\d*)[^a-zA-Z\\d]*(.*)

顺便说一下，您可以使用不区分大小写的匹配来简化此操作.如果您无法在您的工具中激活它，您可以在正则表达式中内联:

By the way, you can simplify this, using case-insensitive matching. If you cannot activate it in your tool, you can do it inline in the regex:

(?i)(.*?)case[^a-z\\d]*(\\d+)[^a-z\\d]*(.*)

请注意，我还简化了数字.+ 表示出现 1 次或多次.

Note that I also simplified the number. + means 1 or more occurrence.

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