PHP update url in variable

$link = http://site.com/view/page.php?id=50&reviews=show

How can we add &extra=video after id=50?

• id is always numeric.
• url can have many other variables after ?id=50
• &extra=video should be added before the first & and after the 50 (value of id)

It will be used this way:

echo '<a href="' . $link . '">Get video</a>';

Thanks.

As Treffynnon says, the order seldomly matters. However, if you really need if for some reason, just use

• parse_url to get the querystring
• parse_str to create an array of parameter
• array_splice to inject a parameter
• http_build_query to rebuild a proper query string

This will do it for you

<?php 
    $linkArray = explode('&',$link);
    $linkArray[0] += '&extra=video';
    $link = implode('&',$linkArray);
?>

1. Explode will split the link string at every &, so it doesn't care how many elements you have in the url.

2. The first element, will be everything including the id=## before the first & sign. So we append whatever you want to appear after it.

3. We put our array together again as a string, separating each element by an &.

Is ID always the first post parameter? If so, then you could jsut do some sort of string manipulation. Use strpos($link, "&") to find out the position where you want to insert. Then do a few substr() based on that position and then append them all together. Its kind of hacky I know, but it will definitely work.

$pos = strpos($link, "&");
$first  = substr($link, 0, $pos);
$last = substr($link, $pos);
$extra = "&extra=video";
$newLink = $first . $extra . $last;

See this link for some of the string manipulation functions that I mentioned above: http://us3.php.net/strings

i would suggest to use functions specifically aimed at url parsing, not general string functions:

$link = 'http://site.com/view/?id=50&reviews=show';
$query = array();
parse_str(parse_url($link, PHP_URL_QUERY), $query);
$query['extra'] = 'video';
$linkNew = http_build_url($link, array('query' => http_build_query($query)));