如何使用 Perl 在 Regex 中使用分词、星号、分词? [英] How to use word break, asterisk, word break in Regex with Perl?

问题描述

我在 Perl 中有一个复杂的预编译正则表达式.在大多数情况下，正则表达式很好，可以匹配它应该匹配的所有内容，而没有不应该匹配的内容.除了一分.

基本上我的正则表达式如下:

my $regexp = qr/\b(FOO|BAR|\*)\b/;

不幸的是 m/\b\*\b/ 与 example, * 不匹配.只有 m/\*/ 会做，因为误报我不能使用.有什么解决办法吗?

来自评论 - 误报是:**、example*、exam*ple

正则表达式的用途是什么?- 它应该提取同事输入到产品数据中的关键字(一个是单个星号).目标是将这些信息从自由文本字段中移到原子字段中.

解决方案

听起来您想将 * 视为单词字符.

<代码>\b

相当于

(?x: (?

你想要

(?x: (?

申请后，您将获得以下内容:

qr/(?: (?<![\w*])(?=[\w*]) | (?<=[\w*])(?![\w*]) )(FOO|酒吧|\*)(?: (?<![\w*])(?=[\w*]) | (?<=[\w*])(?![\w*]) )/X

但鉴于我们对中间表达式的了解，可以将其简化为以下内容:

qr/(?

I have a complexe precompiled regular expression in Perl. For most cases the regex is fine and matches everything it should and nothing it shouldn't. Except one point.

Basically my regex looks like:

my $regexp = qr/\b(FOO|BAR|\*)\b/;

Unfortunately m/\b\*\b/ won't match example, *. Only m/\*/ will do which I can't use because of false positives. Is there any workaround?

from the comments - false positives are: **, example*, exam*ple

what the regex is intended for? - It should extract keywords (one is a single asterisk) coworkers have entered into product data. the goal is to move this information out of a freetext field into an atomic one.

解决方案

It sounds like you want to treat * as a word character.

\b

is equivalent to

(?x: (?<!\w)(?=\w) | (?<=\w)(?!\w) )

so you want

(?x: (?<![\w*])(?=[\w*]) | (?<=[\w*])(?![\w*]) )

Applied, you get the following:

qr/
    (?: (?<![\w*])(?=[\w*]) | (?<=[\w*])(?![\w*]) )
    (FOO|BAR|\*)
    (?: (?<![\w*])(?=[\w*]) | (?<=[\w*])(?![\w*]) )
/x

But given our knowledge of the middle expression, that can be simplified to the following:

qr/(?<![\w*])(FOO|BAR|\*)(?![\w*])/

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