<?php
$str = "I bought _ sheep";
preg_match("/I bought (.*?) sheep", $str, $match);
print_r($match);
?>

http://sandbox.phpcode.eu/g/b2243.php

(.*?)不适合我。我试图匹配注释周围的/* */，其中可能包含多行。

试试这个:

([a]|[^a])

这个正则表达式匹配a或除a之外的任何东西，当然，它意味着匹配所有东西。

顺便说一句，在我的情况下，/\*([a]|[^a])*/匹配C风格的注释。

感谢@mpen提供了一个更简洁的方式。

[\s\S]

一个选项是空正则表达式，在JavaScript中表示为/(?:)/。(也可以使用new RegExp())。逻辑上，一个空正则表达式应该匹配在任何位置包含“空”的字符串——当然是所有的字符串。

请参阅这个SO问题和这篇博客文章进行讨论和更多细节。

我用这个:(.|\n)+对我来说就像一个魅力!

Regex: /I bought.*sheep./ Matches - the whole string till the end of line I bought sheep. I bought a sheep. I bought five sheep. Regex: /I bought(.*)sheep./ Matches - the whole string and also capture the sub string within () for further use I bought sheep. I bought a sheep. I bought five sheep. I boughtsheep. I bought a sheep. I bought fivesheep. Example using Javascript/Regex 'I bought sheep. I bought a sheep. I bought five sheep.'.match(/I bought(.*)sheep./)[0]; Output: "I bought sheep. I bought a sheep. I bought five sheep." 'I bought sheep. I bought a sheep. I bought five sheep.'.match(/I bought(.*)sheep./)[1]; Output: " sheep. I bought a sheep. I bought five "

(.*?)匹配任何东西-我已经使用它很多年了。