Find and replace html links with PHP

Here is a great function that I’m using in a handy string utility class. It takes a string of text (plain text or html) and finds any web addresses ie http://www.purepixel.co.uk/ and turns them into html links (<a> tags).

function parseLinks($str) {
	return ereg_replace("[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]","<a href=\"\\0\">\\0</a>", $str);
}