PHP preg_replace - Very quick question

Question

Masters of regular expressions, please help!

See this string:

$string = "http://www.url.com/?fieldA=123&fieldB=456&fieldC=789";

Assuming "fieldB" always has a positive non-decimal numerical value (but not necessarily three digits long), what preg_replace command do I need to remove it completely, such that the string will then read:

$string = "http://www.url.com/?fieldA=123&fieldC=789";

Thanks!

Answer 1

$string = preg_replace('/&?fieldB=[0-9]+/', '', $string);

Answer 2

$string = preg_replce('/fieldB=([0-9]+)/', '', $string);

Answer 3

Try this:

$string = preg_replace('/&fieldB=[0-9]+/', '', $string);

Working example code:

$string = "http://www.url.com/?fieldA=123&fieldB=456&fieldC=789";
$string = preg_replace('/&fieldB=[0-9]+/', '', $string);
echo $string;

//gives http://www.url.com/?fieldA=123&fieldC=789

Answer 4

With preg_replace():

$url = preg_replace('!&?fieldB=\d+!', '', $string);

You should remove the & before it as well. Also, don't use [0-9]. Use \d instead.

That being said, PHP has good native functions for manipulating URLs. Another way to do this:

$url = parse_url($string);
parse_str($url['query'], $query);
unset($query['fieldB']);
$url['query'] = http_build_query($query);
$string = http_build_url($url);

Note: Unfortunately, the HTTP extension is not a standard extension so you have to install it.