Add Querystring Variable with Multiple Values PHP - php

Question

I found a bit of code for stripping a query string and adding a new value to it, but I want to be able to do this with an array of options. Could someone give me a hand in modifying this code to do that?
Current code:
function add_querystring_var($url, $key, $value) {
$url = preg_replace('/(.*)(\?|&)' . $key . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&');
$url = substr($url, 0, -1);
$value = $value ? "=".urlencode($value) : '';
if (strpos($url, '?') === false)
return ($url . '?' . $key . $value);
else
return ($url . '&' . $key . $value);
}
And I want it to do a foreach for each key and value given and then rebuild the new url.
Example: add_querystring_var(curPageURL(), array("order","sort"), array("swn","DESC"))
So I want the following URL http://www.example.com/students when put through the example above would return http://www.example.com/students?order=swn&sort=DESC
Does anyone know how I can do this? I'm new to this area of PHP. :)
UPDATE:
I forgot to mention sometimes the url may have other queries in it, so I want it to replace the ones that I enter into my array.
Example 1: http://www.example.com/students?page=2 would need to turn into http://www.example.com/students?page=2&order=swn&sort=DESC
Example 2: http://www.example.com/students?page=2&order=name&sort=ASC would need to turn into http://www.example.com/students?page=2&order=swn&sort=DESC

Answer 1

function add_querystring_var($url, $additions) {
$parsed = parse_url($url);
if (isset($parsed['query'])) {
parse_str($parsed['query'], $query);
} else {
$query = array();
}
$parsed['query'] = http_build_query(array_merge($query, $additions));
return http_build_url($parsed);
}
Use it this way:
$new_url = add_querystring_var($url, array('order' => 'swn', 'sort' => 'DESC'));
If you're getting errors saying that http_build_url is not defined, see
PHP http_build_url() and PECL Install

Answer 2

You're kind of reinventing the wheel with that function... first off, you'd be better off using urlencode() on your key/value data rather than that regular expression (and I see that you're not encoding your value string at all)
As dpDesignz mentions in his comment - there is a built-in function available: http_build_query()
$querydata = array('foo' => array('bar', 'baz'),
'baz'=>'boom',
'cow'=>'milk',
'php'=>'hypertext processor');
$querystring = http_build_query($data, '', '&');
Or, to use your example:
$querydata = array("order" => "swn", "sort" => "DESC");
$url = curPageURL();
$concat = "?";
if (strpos($url, "?") !== false)) {
$concat = "&"
}
$url .= $concat . http_build_query($data, '', '&');