Creating an array with specific keys and strings into one array - php

Question

I created a function that gets the product_id and its category_id where the product_id = the product_id supplied like so:
public function getCategorys($product_id){
$sql = "SELECT category_id,product_id FROM oc_product_to_category WHERE product_id = '$product_id'";
$result = $this->query($sql);
$categories = $this->getResult($result);
return $categories;
}
This is function is called with the following code:
foreach($product_ids as $product_id){
$categories[] = $data->getCategorys($product_id);
}
I then create an array containing the product_id and each category_id that product is found in, I did this with the following code:
$product_categories = array();
foreach($categories as $category){
foreach($category as $cat){
if($cat['product_id'])
$product_categories[] = array(
'product_id' => $cat['product_id'],
'category_id' => $cat['category_id']
);
}
}
Now when I print_r($product_categories) I get the following result (this is just part of it I wont put the full array in because its large):
Array
(
[0] => Array
(
[product_id] => 9319
[category_id] => 293
)
[1] => Array
(
[product_id] => 9319
[category_id] => 313
)
[2] => Array
(
[product_id] => 11969
[category_id] => 395
)
[3] => Array
(
[product_id] => 11969
[category_id] => 396
)
Now what I'm trying to achieve is: I want an array that has the product ID and each category_id that it is found in so for example the first two arrays with product id 9319 and 11969 I would want that to look like this:
[0] => Array
(
[product_id] => 9319
[category_id] => 293,313
)
[1] => Array
(
[product_id] => 11969
[category_id] => 395,396
)
I know this isn't articulated very well but I'm not sure how else to phrase this question! I essentially want all the duplicate product id's removed and all their category_id's as one comma separated string in the same array.
EDIT:
I tried the answer provided Group array by subarray values
However I'm getting this output instead now:
Array
(
[22] => Array
(
[133] => Array
(
[product_id] => 22
[category_id] => 313
)
)
[59] => Array
(
[320] => Array
(
[product_id] => 59
[category_id] => 294
)
[321] => Array
(
[product_id] => 59
[category_id] => 331
)
)
[63] => Array
(
[368] => Array
(
[product_id] => 63
[category_id] => 292
)
[369] => Array
(
[product_id] => 63
[category_id] => 302
)
)
[87] => Array
(
[51] => Array
(
[product_id] => 87
[category_id] => 293
)
[52] => Array
(
[product_id] => 87
[category_id] => 313
)
)
This is nearly close to what I want but I want all the category ids in array for that product_id.

Answer 1

Would you not be better off with an array that has the product_id as the key which contained an array of category_id's Comma delimited lists mark the entry point to the road to hell
Make you foreach loop do this instead
$product_categories = [];
foreach($categories as $cat){
$product_categories[$cat['product_id']][] = $cat['category_id'];
}