如果找不到给定的文本，则匹配正则表达式，并尽可能少地匹配 [英] Regex to match if given text is not found and match as little as possible

问题描述

我有文字:

<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>
<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>
<a>
sdfsdf
<b>BBzz</b>
sdfsdf
</a>
<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>

我无法将其解析为xml.我需要在这里使用正则表达式.但这只是一个例子.

I can't parse it as xml. I need to use regex here. Also this is only example.

我希望正则表达式能够将不包含元素b的每个组<a>...</a>与以BB开头的文本进行匹配.

I want regex that can match every group <a>...</a> that does not contain element b with text that starts with BB.

我想出了这个正则表达式: <a>.*?<b>(?!B).*?</b>.*?</a> 但它匹配的最后一组为:

I came up with this regex: <a>.*?<b>(?!B).*?</b>.*?</a> But it matches last group as:

<a>
sdfsdf
<b>BBzz</b>
sdfsdf
</a>
<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>

哪个对我有害?

如何编写仅与给定示例中的那3组匹配的正则表达式?:

1.

<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>

2.

<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>

3.

<a>
sdfsdf
<b>DDzz</b>
sdfsdf
</a>

推荐答案

使用脾气暴躁的令牌正则表达式:

Use a tempered greedy token regex:

<a>(?:(?!<(?:b>BB|/?a>)).)*</a>

启用 .匹配换行符选项.

Enable the . matches newline option.

详细信息:

• <a>-文字<a>字符序列
• (?:(?!<(?:b>BB|/?a>)).)*-与任何字符(.)匹配的脾气暴躁的令牌，该字符不是可以与(?!<(?:b>BB|/?a>))前瞻(不是<b>BB或或<a>序列)
• </a>-文字</a>字符序列

• <a> - a literal <a> char sequence
• (?:(?!<(?:b>BB|/?a>)).)* - a tempered greedy token matching any char (.) that is not the starting symbol of a sequence that can be matched with the pattern inside the (?!<(?:b>BB|/?a>)) lookahead (not a <b>BB or </a> or <a> sequence)
• </a> - a literal </a> char sequence

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