PHP Array Functions
count · sum · diff · intersect · chunk · combine

<?php
// Basic count
$fruits = ["Apple", "Mango", "Banana"];
echo count($fruits); // 3
echo sizeof($fruits); // 3 (alias)

// Empty checks
echo count([]); // 0
echo count(null); // 0

// COUNT_RECURSIVE — nested arrays भी count
$students = [
  ["Rahul", "Priya"],
  ["Amit", "Neha", "Raj"],
];
echo count($students); // 2 (outer arrays)
echo count($students, COUNT_RECURSIVE); // 7 (2 + 5 inner)

// Real world — pagination
$products = range(1, 47); // 47 products
$perPage = 10;
$totalPages = ceil(count($products) / $perPage);
echo "Total Pages: $totalPages"; // 5
?>

<?php
$prices = [450, 799, 299, 199, 650];

// array_sum — total जोड़
echo array_sum($prices); // 2397

// array_product — सब गुणा
$factors = [2, 3, 4];
echo array_product($factors); // 24 (2×3×4)

// min() — सबसे छोटा
echo min($prices); // 199
echo min(5, 2, 8, 1); // 1 (direct values भी)

// max() — सबसे बड़ा
echo max($prices); // 799
echo max(5, 2, 8, 1); // 8

// Average (average PHP में built-in नहीं)
$avg = array_sum($prices) / count($prices);
echo round($avg, 2); // 479.40
?>

<?php
$cart = [
  ["name" => "PHP Book", "price" => 450, "qty" => 2],
  ["name" => "Laravel", "price" => 799, "qty" => 1],
  ["name" => "MySQL Notes", "price" => 299, "qty" => 3],
];

$lineTotal = array_map(fn($i) => $i["price"] * $i["qty"], $cart);
$subtotal = array_sum($lineTotal); // 2594
$gst = $subtotal * 0.18;
$total = $subtotal + $gst;

$allPrices = array_map(fn($i) => $i["price"], $cart);
echo "Cheapest: ₹" . min($allPrices); // ₹299
echo "Costliest: ₹" . max($allPrices); // ₹799
echo "Subtotal: ₹" . number_format($subtotal, 2); // ₹2,594.00
echo "Total: ₹" . number_format($total, 2); // ₹3,060.92
?>

<?php
$a = [1, 2, 3, 4, 5];
$b = [3, 4, 5, 6, 7];

// A में है, B में नहीं
print_r(array_diff($a, $b)); // [1, 2]

// B में है, A में नहीं
print_r(array_diff($b, $a)); // [6, 7]

// Multiple arrays diff
$c = [1, 8];
print_r(array_diff($a, $b, $c)); // [2] — 1 is in $c too

// array_diff_key — keys से compare
$user1 = ["naam" => "Rahul", "age" => 25, "city" => "Delhi"];
$user2 = ["naam" => "Priya", "age" => 22];
print_r(array_diff_key($user1, $user2));
// ["city"=>"Delhi"] — user1 में है, user2 में key नहीं
?>

<?php
// 1. Missing required fields check
$required = ["naam", "email", "phone", "city"];
$submitted = ["naam", "email"];
$missing = array_diff($required, $submitted);
if (!empty($missing)) {
  echo "Missing: " . implode(", ", $missing);
  // Missing: phone, city
}

// 2. New features in update
$oldFeatures = ["login", "register", "profile"];
$newFeatures = ["login", "register", "profile", "dashboard", "reports"];
$added = array_diff($newFeatures, $oldFeatures);
echo "New features: " . implode(", ", $added);
// New features: dashboard, reports
?>

<?php
$a = [1, 2, 3, 4, 5];
$b = [3, 4, 5, 6, 7];

// Common values
print_r(array_intersect($a, $b)); // [3, 4, 5]

// 1. Common tags (Blog)
$post1Tags = ["PHP", "Web", "Laravel", "MySQL"];
$post2Tags = ["PHP", "MySQL", "Database"];
$common = array_values(array_intersect($post1Tags, $post2Tags));
echo "Related tags: " . implode(", ", $common);
// Related tags: PHP, MySQL

// 2. Common user roles/permissions
$userPerms = ["read", "write", "delete"];
$pagePerms = ["read", "write"];
$allowed = array_intersect($userPerms, $pagePerms);
echo "Can: " . implode(", ", $allowed);
// Can: read, write

// 3. Mutual friends
$rahulFriends = ["Priya", "Amit", "Neha", "Raj"];
$priyaFriends = ["Rahul", "Amit", "Neha", "Sita"];
$mutual = array_values(array_intersect($rahulFriends, $priyaFriends));
echo count($mutual) . " mutual friends: " . implode(", ", $mutual);
// 2 mutual friends: Amit, Neha
?>

<?php
$products = ["A","B","C","D","E","F","G","H"];

// 3 per chunk
$pages = array_chunk($products, 3);
print_r($pages);
// [[A,B,C], [D,E,F], [G,H]]

// Page 1 display करना
$page = 1;
$perPage = 3;
$chunks = array_chunk($products, $perPage);
$currentPage = $chunks[$page - 1] ?? [];
echo implode(", ", $currentPage); // A, B, C

// HTML grid — 4 columns
$rows = array_chunk($products, 4);
foreach ($rows as $row) {
  echo "<div class='row'>";
  foreach ($row as $item) {
    echo "<div class='col'>$item</div>";
  }
  echo "</div>";
}

// Batch email sending
$emails = range(1, 100); // 100 emails
$batches = array_chunk($emails, 10); // 10 batches of 10
foreach ($batches as $batch) {
  echo "Sending batch of " . count($batch) . " emails\n";
}
?>

<?php
$keys = ["naam", "umar", "city"];
$values = ["Rahul", 25, "Delhi"];
$user = array_combine($keys, $values);
print_r($user);
// ["naam"=>"Rahul", "umar"=>25, "city"=>"Delhi"]

// CSV header + row combine
$headers = ["id", "name", "price", "stock"];
$row = ["101", "PHP Book", "450", "50"];
$product = array_combine($headers, $row);
echo $product["name"]; // PHP Book
echo $product["price"]; // 450

// Multiple CSV rows process करना
$csvData = [
  ["101", "PHP Book", "450"],
  ["102", "Laravel", "799"],
];
$headers = ["id", "name", "price"];
$products = array_map(
  fn($row) => array_combine($headers, $row),
  $csvData
);
print_r($products);
// [{id:101, name:PHP Book, price:450}, ...]
?>

<?php
$arr = [1, 2, 3];

// Right pad (positive length)
print_r(array_pad($arr, 5, 0));
// [1, 2, 3, 0, 0]

// Left pad (negative length)
print_r(array_pad($arr, -5, 0));
// [0, 0, 1, 2, 3]

// Already >= size — no change
print_r(array_pad($arr, 2, 0));
// [1, 2, 3] — no padding (size >= 2)

// Real world — weekly schedule (7 days)
$tasks = ["Meeting", "Deploy"];
$week = array_pad($tasks, 7, "Free");
print_r($week);
// [Meeting, Deploy, Free, Free, Free, Free, Free]
?>