PHP的preg_match非贪婪? [英] php preg_match non greedy?

问题描述

我有一个字符串(来自文件):

I have a string (from a file):

ILX (New for 2013!)

Overview: The least expensive route to Honda's premium-label goodness

Drivetrain: Two four-cylinder engines to choose from as well as a gas-electric hybrid; front-wheel-drive only.

我如何获取字符串:

$writeup = file_get_contents($car_files_path . $manufacture . '/Stories/'.$story);

我要匹配概览行(Overview: The least expensive route to Honda's premium-label goodness).实现此目标的最佳方法是什么.

I want to match the overview line (Overview: The least expensive route to Honda's premium-label goodness). What is the best way to achieve this.

我尝试了.* \ n，但这将匹配所有内容，然后匹配新行.有没有办法使正则表达式不贪心?

I tried .*\n, but that will match everything and then a new line. Is there a way to make regex non-greedy?

我尝试过: preg_match('/^Overview:\s.*$/im', $writeup, $overall_matches)，我没有找到任何匹配项

I have tried: preg_match('/^Overview:\s.*$/im', $writeup, $overall_matches) and I don't get any matches

推荐答案

在量词后添加?以使其不贪心.在这种情况下，您的正则表达式为.*?\n.

Add ? after the quantifier to make it ungreedy. In this case, your regex would be .*?\n.

要专门匹配以"Overview:"开头的行，请使用此正则表达式:

To specifically match the line beginning with "Overview: ", use this regex:

/^Overview:\s.*$/im

m修饰符允许^和$匹配行的开头和结尾，而不是整个搜索字符串.请注意，除非.与换行符不匹配，否则除非您使用s修饰符，否则无需使其变得不愉快-实际上，在此处使其不愉快对性能不利.

The m modifier allows ^ and $ to match the start and end of lines instead of the entire search string. Note that there is no need to make it ungreedy since . does not match newlines unless you use the s modifier - in fact, making it ungreedy here would be bad for performance.

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