php; remove single variable value pair from querystring

Question

I have a page that lists out items according to numerous parameters ie variables with values.

listitems.php?color=green&size=small&cat=pants&pa         


        

Answer 1

Here's my shot:

/**
*   Receives a URL string and a query string to remove. Returns URL without the query string
*/
function remove_url_query($url, $key) {
    $url = preg_replace('/(?:&|(\?))' . $key . '=[^&]*(?(1)&|)?/i', "$1", $url);
    $url = rtrim($url, '?');
    $url = rtrim($url, '&');
    return $url;
}

Returns:

remove_url_query('http://example.com?a', 'a') => http://example.com
remove_url_query('http://example.com?a=1', 'a') => http:/example.com
remove_url_query('http://example.com?a=1&b=2', 'a') => http://example.com?b=2

Kudos to David Walsh.