正则表达式匹配模式，但排除一组单词 [英] Regex to match a pattern, but exclude a set of words

问题描述

我一直在查看 SO，虽然这个问题已经在一种情况下得到了回答:

I have been looking through SO and although this question has been answered in one scenario:

正则表达式匹配除给定列表之外的所有单词

这不是我想要的.我正在尝试编写一个正则表达式，它匹配 [\w]+[(] 形式的任何字符串，但它不匹配三个字符串cat("、dog("和sheep(").特别是.

It's not quite what I'm looking for. I am trying to write a regular expression which matches any string of the form [\w]+[(], but which doesn't match the three strings "cat(", "dog(" and "sheep(" specifically.

我一直在玩向前看和向后看，但我不能完全到达那里.我可能使这个问题过于复杂，因此我们将不胜感激.

I have been playing with lookahead and lookbehind, but I can't quite get there. I may be overcomplicating this, so any help would be greatly appreciated.

推荐答案

如果正则表达式实现支持 前瞻或后视断言，您可以使用以下内容:

If the regular expression implementation supports look-ahead or look-behind assertions, you could use the following:

• 使用否定前瞻断言:

• Using a negative look-ahead assertion:

 \b(?!(?:cat|dog|sheep)\()\w+\(

使用否定的后视断言:

Using a negative look-behind assertion:

 \b\w+\((?<!\b(?:cat|dog|sheep)\()

我添加了标记 单词边界的 \b 锚点.所以 catdog( 将被匹配，尽管它包含 dog(.

I added the \b anchor that marks a word boundary. So catdog( would be matched although it contains dog(.

但是，虽然正则表达式实现更广泛地支持前瞻断言，但带有后视断言的正则表达式更有效，因为它只测试前面的正则表达式(在我们的例子中\b\w+\() 已经匹配.然而，先行断言将在之前测试实际正则表达式匹配.所以在我们的例子中，只要 \b 匹配.

But while look-ahead assertions are more widely supported by regex implementations, the regex with the look-behind assertion is more efficient since it’s only tested if the preceding regex (in our case \b\w+\() already did match. However the look-ahead assertion would be tested before the actual regex would match. So in our case the look-ahead assertion is tested whenever \b is matched.

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