How to use multidimensional array PHP - php

Question

What i want is:
Array-one (the product db array):
Product id
Cat name
Array-two (the category db array):
cat id
Cat name
if Array-one: cat name is equal to Array-two: cat name add all product ids under the cat id
//this foreach is loop to products
foreach($objects as $object) {
//get cat name from product db
$cat_name_product = $object['values']['17'];
// this foreach is loop to cat db
foreach($cat_db as $cat_object) {
// get cat name from cat db
$cat_name_cat_table = $cat_object['values'][2];
// if cat from product DB is equal to cat name from cat DB
if($cat_name_product == $cat_name_cat_table){
$cat_name_product_id = $object['id'];
$cat_name_db_id = $cat_object['id'];
// Add products ids to a specfic row id from cat
$cat_db_row[$cat_name_db_id][] = $cat_name_product_id;
}
}
}
Result array:
Array
(
[45156381272] => Array
(
[0] => 44990952854
)
[45002415686] => Array
(
[0] => 45054787942
[1] => 45056971448
[2] => 45049917079
[3] => 45056971449
)
)
what i want:
Array
(
[0] => (
[cat_id] => 45156381272
[product_ids] => Array
(
[0] => 44990952854
)
)
[1] =>
[cat_id] => 45156381272
[product_ids] => Array
(
[0] => 45054787942
[1] => 45056971448
[2] => 45049917079
[3] => 45056971449
)
)
How do i do this?

Answer 1

My code gets the desired result:
Input Data:
$arrayProducts = [["Cat_name" => 'cat example 1', "product_id" => 44990952854],
["Cat_name" => 'cat example 2', "product_id" => 44990952854],
["Cat_name" => 'cat example 2', "product_id" => 44990952854],
["Cat_name" => 'cat example 2', "product_id" => 44990952854],
["Cat_name" => 'cat example 2', "product_id" => 44990952854]];
$arrayCategories = [["cat_id" => 45156381272, "Cat_name" => 'cat example 1'],
["cat_id" => 45002415686, "Cat_name" => 'cat example 2']];
Code:
I iterate first the categories array and then (inner) the products arrays.
<?php
$resultArray = array();
foreach($arrayCategories as $key => $element2) {
$resultArray[$key] = array("cat_id" => $element2["cat_id"], "products_ids" => array());
foreach($arrayProducts as $element1) {
if($element1["Cat_name"] == $element2["Cat_name"]) {
$resultArray[$key]["products_ids"][] = $element1["product_id"];
}
}
}
?>
Output ($resultArray)
array ( 0 => array ( 'cat_id' => 45156381272, 'products_ids' => array ( 0 => 44990952854, ), ), 1 => array ( 'cat_id' => 45002415686, 'products_ids' => array ( 0 => 44990952854, 1 => 44990952854, 2 => 44990952854, 3 => 44990952854, ), ), );

Answer 2

Keep using the category ID as array index, while you are building the array. That is (IMHO) the most efficient way to accumulate the data under that ID - otherwise, you would have to search your array for the index of the item with the category ID of the current record all the time.
Add another dimension below that, for the category ID, and the product IDs:
$cat_db_row[$cat_name_db_id]['cat_id'] = $cat_name_db_id;
$cat_db_row[$cat_name_db_id]['product_ids'][] = $cat_name_product_id;
(Technically, that first line overwrites $cat_db_row[$cat_name_db_id]['cat_id'] again and again - but since it is always with the same category ID value, that doesn’t matter. You could do a check whether $cat_db_row[$cat_name_db_id]['cat_id'] is already set first, but that would have rather little point.)
“Reset” the array keys afterwards, when you are done filling the array, using
$cat_db_row = array_values($cat_db_row);
This will throw away all the existing (top-level) array keys, and re-index the array numerically, starting at 0.