用于标签的NSRegularExpression和带有特殊字符的提及？ [英] NSRegularExpression for hashtags and mentions with special characters?

问题描述

我正在使用以下正则表达式来检测我的应用中的主题标签和提及。

I'm using the following regex expression to detect hashtags and mentions in my app.

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(#|@)(\\w+)" options:NSRegularExpressionCaseInsensitive error:&error];

但我的应用程序中的用户可以在其用户名中使用一些特殊字符。例如 @ user.name 或 @user_name 。不允许有空格。但是，使用thins正则表达式只会检测 @user ，而实际上它应该是 @ user.name 。人质工作完美，但用户名中的特殊字符打破了提及功能。

However users within my app are allowed to use some special characters in their usernames. For example @user.name or @user_name. Spaces are not allowed. However using thins regular expression would only detect @user when it should in fact be @user.name. Hostages work perfectly but the special characters in usernames break the mention functionality.

我真的很新的正则表达式，我不知道我需要改变什么才能解决这个问题。我很确定它可以做什么 \\\\ + + / c $ c>但是我可以做些什么帮助。

I'm really new to regex and I'm not sure what I need to change to fix this. I'm pretty sure its something to do \\w+ but what exactly I could do with some help.

推荐答案

因为您需要在 @ 或＃但是这个序列的最后一个字符必须是单词字符，你可以安全地使用

Since you need to match any non-whitespace characters after @ or # but the last character of this sequence must be a word character, you can safely use

@"[#@]\\S+\\b"

请注意另一组 （＃| @）在转换为字符类 [＃@] 时效率更高（它涉及更少的回溯）。

Note that an alternative group (#|@) works more effeciently when transformed into a character class [#@] (it involves less backtracking).

正则表达式细分：

• [＃@] - 匹配＃或 @ ，1次


• \S + \ b - 匹配1个或多个非空白字符但是最后一个必须是边界一词。

• [#@] - match a # or @, 1 time
• \S+\b - match 1 or more non-whitespace characters but the last one must be at the word boundary.

一个更强化的版本（以确保第一个chara cter ＃ / @ 是一个单词字符，整个用户名长度至少为1个字符）：

A bit more enhanced version (to make sure the first character after #/@ is a word character and the whole username is at least 1 character long):

@"[#@]\\w\\S*\\b"

请注意此第二版不支持 @ - nick.name - 等名称。

Note that this second version will not support such names as @-nick.name-.

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