正则表达式性能优化技巧和窍门 [英] Regex Performance Optimization Tips and Tricks

问题描述

在阅读了相当不错的文章之后关于Java中的正则表达式优化，我想知道创建快速有效的正则表达式的其他好技巧是什么?

After reading a pretty good article on regex optimization in java I was wondering what are the other good tips for creating fast and efficient regular expressions?

推荐答案

1. 当您需要重复分组但又不需要使用来自传统(capturing)组的捕获值时，请使用非捕获组(?:pattern).
2. 在适用的(?>pattern)上，使用原子组(或非回溯子表达式).
3. 通过设计正则表达式来尽早终止不匹配项，避免像瘟疫一样避免灾难性回溯. li>

1. Use the non-capturing group (?:pattern) when you need to repeat a grouping but don't need to use the captured value that comes from a traditional (capturing) group.
2. Use the atomic group (or non-backtracking subexpression) when applicable (?>pattern).
3. Avoid catastrophic backtracking like the plague by designing your regular expressions to terminate early for non-matches.

我制作了一个演示这些技术的视频.我从灾难性回溯文章(x+x+)+y中的非常写得不好的正则表达式开始.然后，经过一系列优化后，我将其速度提高了300万倍，并在每次更改后进行了基准测试.该视频特定于.NET，但其中许多内容也适用于大多数其他正则表达式类型:

I created a video demonstrating these techniques. I started with the very poorly written regular expression in the catastrophic backtracking article (x+x+)+y. And then I made it 3 million times faster after a series of optimizations, benchmarking after every change. The video is specific to .NET but many of these things apply to most other regex flavors as well:

.NET Regex课程:#5:优化

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