帮助编写正则表达式
我有以下字符串：user1 fam [电子邮件受保护] >, user2 fam <[电子邮件受保护]>, .. .
我如何使用正则表达式从该字符串中获取邮件地址。我需要在邮件地址的输出列表中
[email protected]
[email protected]
尝试：
<.*>
但它的输出为 < >：
<[email protected]>
<[email protected]>
谢谢。
ps 谢谢@xanatos 的评论，我使用 Erlang
I have folowing string: user1 fam <[email protected]>, user2 fam <[email protected]>, ...
How can i get mail address from this string with regular expression. I need in output list of mail address
[email protected]
[email protected]
I try:
<.*>
But it's ouput with < >:
<[email protected]>
<[email protected]>
Thank you.
p.s. Thank you @xanatos for comment, I use Erlang
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评论（4）
正如其他人所说，但为了使其更快：
这样，正则表达式就不必回溯（使用建议的其他正则表达式，正则表达式将匹配所有字符串，然后开始回滚以查找
> ;）我要补充一点，由于历史原因，
.和[\s\S]之间存在细微差别。两者都捕获除\n之外的所有字符。第一个 (.) 没有捕获它。因此，通过使用[^>]您可以捕获\n，但这对于您正在做的事情来说不应该成为问题。 http://www.regular-expressions.info/dot.html只是为了完整，因为这是一个经常发生的问题，所以还有另一种变体：（
如果需要，您可以将
.替换为[\s\S]，或者使用 SingleLine 选项如果您的语言支持它，则使.的行为方式不同）。这里的要点是“stop”表达式可以长于一个字符。您可以插入(?!%%)而不是 (?!>)，它会在%%处停止。但我不确定这个变体是否适用于 Erlang（我没有注意到新标签...当我最初阅读问题时它不存在并且我不是 Erlang 程序员...而且看起来至少两个 Erlang 程序员对这个论点有不同的看法:-))As the other have said, but to make it faster:
In this way the Regex won't have to backtrack (with the other Regexes suggested, the Regex will match all the string and then will begin to rollback to find a
>)I'll add that, for historical reasons, there are small differences between the
.and, for example[\s\S]. Both catch all the characters EXCEPT the\n. The first one (.) doesn't catch it. So by using the[^>]you are catching the\n, but this shouldn't be a problem for what you are doing. http://www.regular-expressions.info/dot.htmlJust to be complete, because it's a problem that often happens, there is another variant:
(you can substitute the
.with[\s\S]if you want, or use the SingleLine option if your language supports it, to make the.behave in a different way). The point here is that the "stop" expression can be longer than one character. Instead of (?!>) you could have inserted(?!%%)and it would have stopped at%%. BUT I'm not sure this variant work with Erlang (I hadn't noticed the new Tag... It wasn't there when I orginally read the question and I'm not an Erlang programmer... And it seems at least two Erlang programmers have different opinions on the argument :-) )您需要使用选项
ungreedy，以便它只匹配各个括号对。global，以便您可以获得所有匹配项。并且您需要
{capture, all_but_first, list}以便获得实际值（如果您愿意，list也可以是binary二进制结果）。all_but_first告诉re不要返回整个匹配项（其中包括<>），而只返回组。结果：
You need to use the option
ungreedyso that it only matches the individual bracket pairs.globalso that you can get all the matches.and you need
{capture, all_but_first, list}so that you get the actual values (listcan also bebinaryif you prefer binary results).all_but_firsttellsreto not return the whole match (which would include<>), just the group.Result:
使用团体。有关更多详细信息，请参阅正则表达式引擎的文档。
Use groups. See your regex engine's documentation for more details.
保持简单并使用
<([^>]*)>，它的速度大约是最快的，并且适用于大多数版本的正则表达式。这更快，因为在使用<(.*?)>时永远不必回溯，会导致回溯。Keep it simple and use
<([^>]*)>which is about as fast as it can get and works for most versions of regular expressions. This is faster as it never has to backtrack while using<(.*?)>will cause backtracking.