Fatal error, not quite sure why? - php

Question

I think this is just something I haven't come across before!
$r = $database->currentChallengers($f, $g);
while($row=mysql_fetch_assoc($r))
{
$u[]=$row['username'];
$i[]=$row['userid'];
$s[]=$row['streak'];
}
for ($i = 0; $i < count($u); $i++)
{
foreach ($u as $user)
{
echo "Challenger: $u[$i]";
}
}
That PHP is for the following database query:
function currentChallengers($f, $g)
{
$q = "SELECT k.userid, k.streak, u.username
FROM ".TBL_KOTH." k
INNER JOIN ".TBL_USERS." u
ON k.userid = u.id
WHERE k.format = '$f' && k.game = '$g' && k.king = '0' && k.done = '0'
ORDER BY k.userid";
return mysql_query($q, $this->connection);
}
I am getting the error
Fatal error: [] operator not supported for strings
On the line
$u[]=$row['username'];
Could anyone tell me why this is happening?
Also, should the code I have written list each username from the query?
Thanks

Answer 1

The other answers already point out what you need to do: Use an array. But before that, check whether $u etc. are being used somewhere else in the code already. You could get in trouble because they may already be in use elsewhere - as strings.
And, you should really use some more verbose variable names to avoid building a maintenance nightmare. Why not use for example
$username[] = $row['username'];
$userid[] = $row['userid'];
$streak[] = $row['streak'];
}

Answer 2

PHP seems to be assuming your uninitialized variables are strings. See Pekka's Answer. Try initializing/declaring those variables before you start pushing values onto them.
$u = array();
$i = array();
$s = array();

Answer 3

Use meaningfull variable names.
You have used $u to store a string somewhere above this code.
Probably you stored a username in it.
So I recommend using variables $username and $users.
And set $users = array(); before a loop, as proposed by Mike/

Answer 4

What are you trying to do with $u[]=$row['username'];? $u is currently a string and you can't write to a specific index of a string (you haven't specified any index either).
If you're trying to store rows in to arrays, declare them as arrays and use an iterating variable to populate it.
$u = array();
$i = array();
$s = array();
$k = 0;
while($row=mysql_fetch_assoc($r))
{
$u[$k] = $row['username'];
$i[$k] = $row['userid'];
$s[$k] = $row['streak'];
$k = $k + 1;
}

Answer 5

Try this, instead of arrays :
$u=$row['username'];
$i=$row['userid'];
$s=$row['streak'];

Answer 6

Are you sure that $u is not already defined? Initialize it with $u = array(); before the first "while"...

Answer 7

The problem seems to come to the fact that $u (and possibly $s and $i) seems to be a string.
Try adding:
$u = array();
$s = array();
$i = array();
before:
$r = $database->currentChallengers($f, $g);

Answer 8

You should add $u = array() before accessing it. You probably use some other $u as a string in another part of your script and PHP still believe it's the same one.