how to convert this ??

[PHPycho]

Hello forums !!
suppose i had following string

$string = "hello friends . My site is http://$sitenamefromdb.com";

I want to know:
1> how to convert the string: http://example.com is converted into a link .
ie when $string is displayed ie

echo $string;

, a link should appear instead of plain text. ie <a href="http://$sitenamefromdb.com">http://$sitenamefromdb.com</a>
Note: if the $sitenamefromdb was static i could solve using str_replace, since its dynamic as it comes from the db. i didnt get the idea..
i think we should search http:// or www. in a word of a string and replace that word...
Please help me..
Thanks in advance to all of you !!

[scross]

You'll need to use regular expressions: http://www.regular-expressions.info

I guess the easiest way would be to locate a http/https url by something like:

!(https?://.+?)(\s|$)!i

and then just link it to itself:

<a href="URL">URL</a>

I guess the code would look something like:

$string = "hello friends . My site is http://$sitenamefromdb.com";
$string = preg_replace('!(https?://.+?)(\s|$)!i', '<a href="\\1">\\1</a>\\2', $string);
echo $string;

but this is untested code. You could also use parse_url() to attempt to break the url up into bits if you wished.