如何替换 ruby​​ 中最后一次出现的子字符串? [英] How to replace the last occurrence of a substring in ruby?

问题描述

我想替换 Ruby 中最后一次出现的子字符串.最简单的方法是什么?例如，在abc123abc123中，我想将最后一个abc替换为ABC.我该怎么做?

I want to replace the last occurrence of a substring in Ruby. What's the easiest way? For example, in abc123abc123, I want to replace the last abc to ABC. How do I do that?

推荐答案

从 Ruby 2.0 开始，我们可以使用 \K 从返回的匹配项中删除在它之前匹配的任何文本.结合贪婪的运算符，你会得到这个:

Since Ruby 2.0 we can use \K which removes any text matched before it from the returned match. Combine with a greedy operator and you get this:

'abc123abc123'.sub(/.*\Kabc/, 'ABC')
#=> "abc123ABC123"

这比 Hirurg103 建议的使用捕获组快约 1.4 倍，但这种速度是以使用鲜为人知的模式降低可读性为代价的.

This is about 1.4 times faster than using capturing groups as Hirurg103 suggested, but that speed comes at the cost of lowering readability by using a lesser-known pattern.

关于 \K 的更多信息:https://www.regular-expressions.info/keep.html

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