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oliverlundquistoliverlundquist
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added files that are featured in the blog post
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Lines changed: 495 additions & 94 deletions

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‎app/ProductSimilarity.php‎

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<?php declare(strict_types=1);
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namespace App;
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use Exception;
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class ProductSimilarity
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{
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protected $products = [];
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protected $featureWeight = 1;
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protected $priceWeight = 1;
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protected $categoryWeight = 1;
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protected $priceHighRange = 1000;
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public function __construct(array $products)
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{
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$this->products = $products;
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$this->priceHighRange = max(array_column($products, 'price'));
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}
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public function setFeatureWeight(float $weight): void
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{
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$this->featureWeight = $weight;
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}
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public function setPriceWeight(float $weight): void
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{
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$this->priceWeight = $weight;
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}
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public function setCategoryWeight(float $weight): void
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{
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$this->categoryWeight = $weight;
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}
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public function calculateSimilarityMatrix(): array
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{
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$matrix = [];
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foreach ($this->products as $product) {
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$similarityScores = [];
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foreach ($this->products as $_product) {
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if ($product->id === $_product->id) {
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continue;
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}
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$similarityScores['product_id_' . $_product->id] = $this->calculateSimilarityScore($product, $_product);
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}
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$matrix['product_id_' . $product->id] = $similarityScores;
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}
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return $matrix;
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}
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public function getProductsSortedBySimularity(int $productId, array $matrix): array
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{
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$similarities = $matrix['product_id_' . $productId] ?? null;
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$sortedProducts = [];
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if (is_null($similarities)) {
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throw new Exception('Can\'t find product with that ID.');
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}
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arsort($similarities);
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foreach ($similarities as $productIdKey => $similarity) {
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$id = intval(str_replace('product_id_', '', $productIdKey));
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$products = array_filter($this->products, function ($product) use ($id) { return $product->id === $id; });
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if (! count($products)) {
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continue;
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}
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$product = $products[array_keys($products)[0]];
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$product->similarity = $similarity;
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$sortedProducts[] = $product;
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}
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return $sortedProducts;
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}
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protected function calculateSimilarityScore($productA, $productB)
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{
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$productAFeatures = implode('', get_object_vars($productA->features));
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$productBFeatures = implode('', get_object_vars($productB->features));
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return array_sum([
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(Similarity::hamming($productAFeatures, $productBFeatures) * $this->featureWeight),
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(Similarity::euclidean(
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Similarity::minMaxNorm([$productA->price], 0, $this->priceHighRange),
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Similarity::minMaxNorm([$productB->price], 0, $this->priceHighRange)
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) * $this->priceWeight),
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(Similarity::jaccard($productA->categories, $productB->categories) * $this->categoryWeight)
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]) / ($this->featureWeight + $this->priceWeight + $this->categoryWeight);
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}
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}

‎app/Similarity.php‎

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<?php declare(strict_types=1);
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namespace App;
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class Similarity
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{
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public static function hamming(string $string1, string $string2, bool $returnDistance = false): float
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{
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$a = str_pad($string1, strlen($string2) - strlen($string1), ' ');
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$b = str_pad($string2, strlen($string1) - strlen($string2), ' ');
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$distance = count(array_diff_assoc(str_split($a), str_split($b)));
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if ($returnDistance) {
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return $distance;
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}
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return (strlen($a) - $distance) / strlen($a);
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}
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public static function euclidean(array $array1, array $array2, bool $returnDistance = false): float
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{
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$a = $array1;
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$b = $array2;
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$set = [];
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foreach ($a as $index => $value) {
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$set[] = $value - $b[$index] ?? 0;
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}
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$distance = sqrt(array_sum(array_map(function ($x) { return pow($x, 2); }, $set)));
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if ($returnDistance) {
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return $distance;
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}
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// doesn't work well with distances larger than 1
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// return 1 / (1 + $distance);
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// so we'll use angular similarity instead
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return 1 - $distance;
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}
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public static function jaccard(string $string1, string $string2, string $separator = ','): float
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{
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$a = explode($separator, $string1);
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$b = explode($separator, $string2);
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$intersection = array_unique(array_intersect($a, $b));
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$union = array_unique(array_merge($a, $b));
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return count($intersection) / count($union);
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}
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public static function minMaxNorm(array $values, $min = null, $max = null): array
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{
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$norm = [];
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$min = $min ?? min($values);
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$max = $max ?? max($values);
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foreach ($values as $value) {
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$numerator = $value - $min;
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$denominator = $max - $min;
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$minMaxNorm = $numerator / $denominator;
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$norm[] = $minMaxNorm;
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}
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return $norm;
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}
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}

‎resources/views/welcome.blade.php‎

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<!doctype html>
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<html lang="{{ str_replace('_', '-', app()->getLocale()) }}">
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>Laravel</title>
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<!-- Fonts -->
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<link href="https://fonts.googleapis.com/css?family=Nunito:200,600" rel="stylesheet">
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<!-- Styles -->
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<style>
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html, body {
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background-color: #fff;
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color: #636b6f;
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font-family: 'Nunito', sans-serif;
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font-weight: 200;
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height: 100vh;
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margin: 0;
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}
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.full-height {
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height: 100vh;
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}
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.flex-center {
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align-items: center;
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display: flex;
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justify-content: center;
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}
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.position-ref {
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position: relative;
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}
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.top-right {
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position: absolute;
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right: 10px;
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top: 18px;
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}
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.content {
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text-align: center;
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}
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.title {
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font-size: 84px;
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}
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.links > a {
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color: #636b6f;
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padding: 0 25px;
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font-size: 13px;
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font-weight: 600;
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letter-spacing: .1rem;
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text-decoration: none;
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text-transform: uppercase;
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}
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.m-b-md {
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margin-bottom: 30px;
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}
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</style>
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</head>
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<body>
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<div class="flex-center position-ref full-height">
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@if (Route::has('login'))
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<div class="top-right links">
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@auth
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<a href="{{ url('/home') }}">Home</a>
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@else
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<a href="{{ route('login') }}">Login</a>
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@if (Route::has('register'))
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<a href="{{ route('register') }}">Register</a>
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@endif
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@endauth
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</div>
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@endif
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<div class="content">
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<div class="title m-b-md">
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Laravel
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
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<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
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<title>Recommender System in Laravel</title>
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<style>
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.large-product-image {
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width: auto;
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height: 200px;
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}
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</style>
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</head>
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<body>
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<div class="container">
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<div class="row mb-5" style="border-bottom: 1px solid #ccc">
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<div class="col text-center">
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<img class="p-3" style="height: 80px; width: auto; border-top: 1px solid #ccc; background-color: #f7f7f7" src="{{ $selectedProduct->image }}" alt="Product Image">
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@foreach ($products as $product)
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<a href="/?id={{ $product->id }}" style="text-decoration: none;">
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<img class="p-3" style="height: 80px; width: auto;" src="{{ $product->image }}" alt="Product Image">
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</a>
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@endforeach
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</div>
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</div>
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<div class="row">
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<div class="offset-3 col-6">
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<h5>Selected Product</h5>
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</div>
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</div>
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<div class="row mb-5">
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<div class="offset-3 col-6">
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<div class="card">
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<div class="text-center" style="background-color: #ccc">
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<img class="large-product-image" src="{{ $selectedProduct->image }}" alt="Product Image">
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</div>
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<div class="card-body">
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<p class="card-text text-muted">{{ $selectedProduct->name }} (${{ $selectedProduct->price }})</p>
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</div>
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</div>
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<div class="links">
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<a href="https://laravel.com/docs">Docs</a>
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<a href="https://laracasts.com">Laracasts</a>
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<a href="https://laravel-news.com">News</a>
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<a href="https://blog.laravel.com">Blog</a>
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<a href="https://nova.laravel.com">Nova</a>
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<a href="https://forge.laravel.com">Forge</a>
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<a href="https://github.com/laravel/laravel">GitHub</a>
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</div>
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</div>
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<div class="row">
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<div class="offset-3 col-6">
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<h5>Similar Products</h5>
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</div>
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</div>
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@foreach ($products as $product)
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<div class="row mb-5">
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<div class="offset-3 col-6">
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<div class="card">
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<div class="text-center" style="background-color: #ccc">
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<img class="large-product-image" src="{{ $product->image }}" alt="Product Image">
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</div>
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<div class="card-body">
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<h5 class="card-title">Similarity: {{ round($product->similarity * 100, 1) }}%</h5>
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<p class="card-text text-muted">{{ $product->name }} (${{ $product->price }})</p>
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</div>
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</div>
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</div>
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</div>
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</body>
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@endforeach
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</div>
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<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
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<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
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</body>
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</html>

‎routes/web.php‎

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*/
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Route::get('/', function () {
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return view('welcome');
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$products = json_decode(file_get_contents(storage_path('data/products-data.json')));
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$selectedId = intval(app('request')->input('id') ?? '8');
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$selectedProduct = $products[0];
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$selectedProducts = array_filter($products, function ($product) use ($selectedId) { return $product->id === $selectedId; });
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if (count($selectedProducts)) {
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$selectedProduct = $selectedProducts[array_keys($selectedProducts)[0]];
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}
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$productSimilarity = new App\ProductSimilarity($products);
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$similarityMatrix = $productSimilarity->calculateSimilarityMatrix();
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$products = $productSimilarity->getProductsSortedBySimularity($selectedId, $similarityMatrix);
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return view('welcome', compact('selectedId', 'selectedProduct', 'products'));
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});

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