arrays - php - How do I fix this illegal offset type error

Question

I'm getting

illegal offset type

error for every iteration of this code. Here's the code :

$s = array();
for($i = 0; $i < 20; $i++){
    $source = $xml->entry[$i]->source;
    $s[$source] += 1;    
}

print_r($s)

Answer 1

Illegal offset type errors occur when you attempt to access an array index using an object or an array as the index key.

Example:

$x = new stdClass();
$arr = array();
echo $arr[$x];
//illegal offset type

Your $xml array contains an object or array at $xml->entry[$i]->source for some value of $i, and when you try to use that as an index key for $s, you get that warning. You'll have to make sure $xml contains what you want it to and that you're accessing it correctly.