SimplePie RSS not accepting variable with comma separated strings - php

Question

I'm trying to use SimplePies "$feed->set_feed_url (array());" function but I am having major difficulty understanding why it wont accept my values.
When I add the URLS manually (i.e directly below), they work just fine. The feeds go through ok and displays the feeds as needed.
$feed ->set_feed_url (array(
'http://www.theverge.com/tag/rss',
'http://feeds.ign.com/ign/all'
));
I have URLS in a database table that I am pulling out like normal with a while loop. I then append a comma and remove the trailing comma so its nice for the SimplePie array. Like so:
while($row = mysqli_fetch_array($pullAllAccountsDoIt)){
$result4mdb .= $row[0] . ",";
}
$result4mdb = substr($result4mdb, 0, strlen($result4mdb) -1);
echo "the result is: " . $result4mdb;
When I do this, and echo out "$result4mdb", it prints out: the result is: http://www.gamespot.com/feeds/mashup/,http://www.theverge.com/tag/rss
Meaning that the variable is good and printing out what i need. So far so good.
I then go into the simplePie code, put in my varialble like so:
$feed ->set_feed_url (array($result4mdb));
and nothing happens. I don't get any errors or anything, just that the page stays blank and nothing comes up.
For testing, I do a gettype($result4mdb); and it tells me that the variable is a "string" and again, the output of this variable when echoed is the URLS it got from the database so I KNOW that the whole process so far is working.
For further testing, I go to the database and remove one of the URLS so that when queried, that it returns one value, and all of the sudden SimplePie works.
I've been searching for a good day and a half now, trying different things and googling as much as possible but to no avail. I just cant quite get it.
I'm at my wits end. Any assistance as to why this isn't working is GREATLY appreciated.
Thank you in advance everyone

Answer 1

You're just producing a string containing comma seperated values. What you need is an array, so just explode() your string:
Change:
$feed ->set_feed_url (array($result4mdb));
to
$feed ->set_feed_url (explode(',', $result4mdb));
More elegant version, change:
while($row = mysqli_fetch_array($pullAllAccountsDoIt)){
$result4mdb .= $row[0] . ",";
}
to
while($row = mysqli_fetch_array($pullAllAccountsDoIt)){
$result4mdb[] = $row[0];
}
This way you're not creating a string that needs to be exploeded, but create an array at first.