从字符串中获取主题标签，替换其中的一些符号并将其转换为链接PHP

Question

I have some string with hashtags looks like @user_name. Now i convert all hashtags to links this way:

$text = preg_replace ("/@(\\w+)/", '<a href="http://$1.'.SITE_NAME.'">@$1</a> ', $text);

As you can see, all hashtags becomes to subdomain names. If you know, there some problems with _ symbol in subdomain names (some browsers not supports that, IE supports, but not set cookies, etc..). So i need to replace the _ symbols in subdomain to - (minus), but keep _ symbols in hashtag view. There link what i need to <a href="http://user-name.site.com">@user_name</a>. How?

Answer 1

You can use preg_replace_callback () like this:

$text = preg_replace_callback ("/@(\\w+)/", function ($matches) {
    return '<a href="http://'. str_replace('_', '-', $matches[1]) .'.abc.com.">'.$matches[1].'</a> '; },  "test @user_john here");