PHP regular expression Twitter links

Here’s a quick piece of code to highlight replies to users in twitter for example @ashleyford this script uses regular expression to find and replace a based on two things. Firstly it checks for a space before the @ symbol and then checks for the space at the end of the users name, it then takes that string and replaces it with a link to the user twitter profile. Useful if you have a dynamic list of tweets that you want to linkify. All you need to do is change $ret to the variable the contains your string.

$ret = preg_replace("#(^|[\n ])@([^ \"\t\n\r<]*)#ise", "'\\1<a href=\"http://www.twitter.com/\\2\" >@\\2</a>'", $ret);

These two lines of code do a similar job with regards the structure however they look for the http:// and www.  to determine a link.

$ret = preg_replace("#(^|[\n ])([\w]+?://[\w]+[^ \"\n\r\t<]*)#ise", "'\\1<a href=\"\\2\" >\\2</a>'", $ret);
$ret = preg_replace("#(^|[\n ])((www|ftp)\.[^ \"\t\n\r<]*)#ise", "'\\1<a href=\"http://\\2\" >\\2</a>'", $ret);