merge.php

<?php
/**
 * This script shows an example of how merge two arrays,
 * where one array contains instances of Products, and the
 * second array contains **multiple** instances of Product
 * Attributes, and where the records in both arrays are
 * linked via some value ($product->id == $attribute->product_id).
 */

/**
 * Example Product class
 */
class Product {
    protected $id;
    protected $name;

    public function __construct($id, $name) {
        $this->setId($id);
        $this->setName($name);
    }

    public function setId($id) {
        $this->id = $id;
    }

    public function getId() {
        return $this->id;
    }

    public function setName($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

/**
 * Example Attribute class
 */
class Attribute {
    protected $product_id;
    protected $name;
    protected $value;

    public function __construct($product_id, $name, $value) {
        $this->setProductId($product_id);
        $this->setName($name);
        $this->setValue($value);
    }

    public function setProductId($id) {
        $this->product_id = $id;
    }

    public function getProductId() {
        return $this->product_id;
    }

    public function setName($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }

    public function setValue($value) {
        $this->value = $value;
    }

    public function getValue() {
        return $this->value;
    }
}

$products = [
    new Product(1, 'Product 1'),
    new Product(2, 'Product 2'),
    new Product(3, 'Product 3'),
];

$attributes = [
    new Attribute(1, 'description', 'Nice product'),
    new Attribute(1, 'price', 10),
    new Attribute(2, 'description', 'Very nice product'),
    new Attribute(2, 'price', 15),
    new Attribute(3, 'description', 'Not so good product'),
    new Attribute(2, 'price', 20),
];

#print_r($products);
#print_r($attributes);

$result = [];
foreach ($products as $product) {
    $fullProduct = new StdClass();
    $fullProduct->id = $product->getId();
    $fullProduct->name = $product->getName();

    $productAttributes = array_filter($attributes, function ($item) use ($product) {
        // Return true for item to pass the filter.
        // Return false for item to be filtered out.
        return $item->getProductId() == $product->getId();
    });

    foreach ($productAttributes as $attribute) {
        $fullProduct->{ $attribute->getName() } = $attribute->getValue();
    }
    $result[] = $fullProduct;
}

print_r($result);
/* OUTPUT:
Array
(
    [0] => stdClass Object
        (
            [id] => 1
            [name] => Product 1
            [description] => Nice product
            [price] => 10
        )

    [1] => stdClass Object
        (
            [id] => 2
            [name] => Product 2
            [description] => Very nice product
            [price] => 20
        )

    [2] => stdClass Object
        (
            [id] => 3
            [name] => Product 3
            [description] => Not so good product
        )

)
*/