如何使用 PHP regexp 匹配字符串中任意位置的确切单词 [英] How to match exact word anywhere in string with PHP regexp

问题描述

我想知道用户是否在其可能的用户名字符串中的任何位置使用了 admin 或 username 词.

I want to find out if user has used the words admin or username anywhere in their possible username string.

所以如果用户想使用admin，或I am admin，或my admin name 或my username>，作为他们的用户名，我希望我的正则表达式能够检测到它.如果他使用 adminmember 我可以忍受，不要检测到它.我还希望检测不区分大小写.

So if user wants to use admin, or I am admin, or my admin name or my username, as their username, I want my regexp to detect it. If he uses adminmember I can live with that, don't detect it. I also want detection to be case insensitive.

到目前为止我得到了这个，但它并没有像我想象的那样工作，因为它会检测它不应该的单词:

So far I got this, but it is not really working as I thought, since it will detect words that it shouldn't:

/^[admin|username]+$/i

这甚至会匹配 adm，但它不应该.我已经尝试过单词边界，但我也无法让它工作，也许我做错了什么.正如您在我的问题中所见，我想检测字符串中任何位置的单词 admin，但如果它是某个单词的一部分，我可以跳过它.

This will match even adm, and it shouldn't. I have tried with word boundaries, but I couldn't make it work either, maybe I did something wrong. As you can see in my question I would like to detect word admin anywhere in the string, but if it is a part of some word I can skip it.

提前致谢.

推荐答案

正则表达式中的方括号不是用于分组，而是用于指定字符类；分组是用括号完成的.您不想使用 ^ 和 $ 来锚定正则表达式，因为它们只会匹配字符串的开头和结尾；您想使用 \b 来匹配单词边界.

Square brackets in a regexp are not for grouping, they're for specifying character classes; grouping is done with parentheses. You don't want to anchor the regexp with ^ and $, because that will only match at the beginning and end of the string; you want to use \b to match word boundaries.

/\b(admin|username)\b/i

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