better way to replace query string value in a given url

Question

Okay.. so basically, say we have a link:

$url = \"http://www.site.com/index.php?sub=Mawson&state=QLD&cat=4&page=2&sort=z\";

Answer 1

function replaceQueryParams($url, $params)
{
    $query = parse_url($url, PHP_URL_QUERY);
    parse_str($query, $oldParams);

    if (empty($oldParams)) {
        return rtrim($url, '?') . '?' . http_build_query($params);
    }

    $params = array_merge($oldParams, $params);

    return preg_replace('#\?.*#', '?' . http_build_query($params), $url);
}

$url examples:

• http://example.com
• http://example.com/
• http://example.com/page
• http://example.com/page?
• http://example.com/page?foo=bar
• http://example.com/page?foo2=bar2
• http://example.com/page?foo=bar&foo2=bar2

$params example:

[
   'foo' => 'not-bar',
]

Note: it doesn't understand URLs with anchors (hashes) like http://example.com/page?foo=bar#section1