how to access the array inside the array in codeigniter? - codeigniter

Question

I am new to CI . I had a function to access a list of data as category. The function was like this:
public function get_category_tree()
{
$this->ci->db->where('is_display','1');
$query = $this->ci->db->get('product_categories');
if ($query->num_rows() > 0)
{
foreach($query->result() as $cat)
{
if($cat->parent_id=='0'){
//category
$categories_arr[$cat->id] = array('id' => $cat->id, 'parent_id'=>$cat->parent_id ,'name' => $cat->name, 'subcat' => '');
}else{
//subcategory;
$categories_arr[$cat->parent_id]['subcat'][] = array('id' => $cat->id, 'parent_id' => $cat->parent_id, 'name' => $cat->name);
}
}
return $categories_arr;
}
return false;
}
this function was defined in general library and i accessed it from the controller like this:
$this->data['category_tree'] = $this->general->get_category_tree();
And this used to give me this result:
Array
(
[id] => 19
[parent_id] => 0
[name] => DVDs & Movies
[subcat] =>
)
Array
(
[id] => 32
[parent_id] => 0
[name] => Stamps
[subcat] => Array
(
[0] => Array
(
[id] => 78
[parent_id] => 32
[name] => Africa
)
[1] => Array
(
[id] => 79
[parent_id] => 32
[name] => Asia
)
[2] => Array
(
[id] => 80
[parent_id] => 32
[name] => Australia
)
[3] => Array
(
[id] => 81
[parent_id] => 32
[name] => Br Comm Other
)
[4] => Array
(
[id] => 82
[parent_id] => 32
[name] => Canada
)
[5] => Array
(
[id] => 83
[parent_id] => 32
[name] => Europe
)
[6] => Array
(
[id] => 84
[parent_id] => 32
[name] => Latin America
)
[7] => Array
(
[id] => 85
[parent_id] => 32
[name] => Middle East
)
[8] => Array
(
[id] => 86
[parent_id] => 32
[name] => Publications
)
[9] => Array
(
[id] => 87
[parent_id] => 32
[name] => Topical & Specialty
)
[10] => Array
(
[id] => 88
[parent_id] => 32
[name] => UK (Great Britain)
)
[11] => Array
(
[id] => 89
[parent_id] => 32
[name] => United States
)
[12] => Array
(
[id] => 90
[parent_id] => 32
[name] => Worldwide
)
)
)
Now i upgraded my php to 7+, now the line
$categories_arr[$cat->parent_id]['subcat'][] = array('id' => $cat->id, 'parent_id' => $cat->parent_id, 'name' => $cat->name);
did not work and gave php error and i simply removed the [] and it became
$categories_arr[$cat->parent_id]['subcat'] = array('id' => $cat->id, 'parent_id' => $cat->parent_id, 'name' => $cat->name);
Now when i print_it it gives me this result:
Array
(
[id] => 19
[parent_id] => 0
[name] => DVDs & Movies
[subcat] =>
)
Array
(
[id] => 32
[parent_id] => 0
[name] => Stamps
[subcat] => Array
(
[id] => 90
[parent_id] => 32
[name] => Worldwide
)
)
Only the last array of the sub array. How can i solve it. I searched a lot about the upgrade and fix for it but couldn't garb anything useful. Can anyone please help. Thanks in advance

Answer 1

Because you define subcat as string by 'subcat' => '' in defining $categories_arr[$cat->id]. Use this:
public function get_category_tree()
{
$this->ci->db->where('is_display','1');
$query = $this->ci->db->get('product_categories');
if ($query->num_rows() > 0)
{
foreach($query->result() as $cat)
{
if($cat->parent_id=='0'){
//category
$categories_arr[$cat->id] = array('id' => $cat->id, 'parent_id'=>$cat->parent_id ,'name' => $cat->name, 'subcat' => array());
}else{
//subcategory;
$categories_arr[$cat->parent_id]['subcat'][] = array('id' => $cat->id, 'parent_id' => $cat->parent_id, 'name' => $cat->name);
}
}
return $categories_arr;
}
return false;
}