Why doesn't this PHP recursive function return the value?

Question

I was working on an API for ustream which returns the following array

Array
(
[results] => Array
    (
        [0] => Array
            (
                 


        

Answer 1

You're not doing anything with the return from your recursion call. It's a bit more complex than simply returning it, because you only want to cascade out if we actually found anything.

Try this:

function recursion($array) {
    foreach ($array as $key => $value) {
        if($key==='sourceChannel') {
            return $value['id'];
        }
        if (is_array($value)) {
            $rc = recursion($value);
            if (!is_null($rc)) return $rc;
        }
    }
    return null;
}

First, I added return null; to the end of the function - if we didn't find anything, we return null.

Then, when I recurse, I check the return value... if it's non-null, it means we found something and we want to return it. If it is null, we don't want to return - we want to continue the loop instead.