المصفوفات المتقدمة والفرز

<?php
$arr1 = ["a" => "apple", "b" => "banana"];
$arr2 = ["b" => "blueberry", "c" => "cherry"];

// array_merge: merge — same-name string keys: latter overwrites former
$merged = array_merge($arr1, $arr2);
// ["a" => "apple", "b" => "blueberry", "c" => "cherry"]

// + operator: merge — same-name keys: former takes priority (keeps left side)
$union = $arr1 + $arr2;
// ["a" => "apple", "b" => "banana", "c" => "cherry"]
// Note: "b" kept "banana" from the left side

// array_merge re-indexes numeric arrays
$nums1 = [1, 2, 3];
$nums2 = [4, 5];
print_r(array_merge($nums1, $nums2));  // [1,2,3,4,5] (re-indexed)
print_r($nums1 + $nums2);              // [1,2,3] (+ doesn't re-index)
?>

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

// array_diff: values in $a but not in $b
print_r(array_diff($a, $b));  // [1, 2, 3]

// array_intersect: values in both $a and $b
print_r(array_intersect($a, $b));  // [4, 5]
?>

<?php
$user = ["name" => "John", "age" => 25, "city" => "New York"];

// array_keys: get all keys
print_r(array_keys($user));
// ["name", "age", "city"]

// array_values: get all values (reset to indexed array)
print_r(array_values($user));
// ["John", 25, "New York"]

// Check key or value
var_dump(array_key_exists("age", $user));  // bool(true)
var_dump(in_array("Chicago", $user));      // bool(false)

// array_search: find the key for a given value
$key = array_search(25, $user);
echo $key;  // "age"
?>

<?php
$numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

// Keep only even numbers
$even = array_filter($numbers, function($n) {
    return $n % 2 == 0;
});
print_r($even);  // [1=>2, 3=>4, 5=>6, 7=>8, 9=>10]
// Note: the keys are preserved! Use array_values to reset them:
print_r(array_values($even));  // [2, 4, 6, 8, 10]

// No callback: filters out values that equal false
$mixed = [0, "hello", "", null, false, "world", []];
$filtered = array_filter($mixed);
print_r($filtered);  // [1=>"hello", 5=>"world"]
?>

<?php
// Clean up a user-submitted form (remove empty fields)
$form = [
    "name" => "John",
    "email" => "",
    "phone" => null,
    "city" => "New York",
    "comment" => false
];

$cleaned = array_filter($form, function($val) {
    return $val !== "" && $val !== null && $val !== false;
});
print_r($cleaned);
// ["name"=>"John", "city"=>"New York"]
?>

<?php
$numbers = [1, 2, 3, 4, 5];

// Multiply every number by 2
$doubled = array_map(function($n) {
    return $n * 2;
}, $numbers);
print_r($doubled);  // [2, 4, 6, 8, 10]

// With an arrow function
$squares = array_map(fn($n) => $n * $n, $numbers);
print_r($squares);  // [1, 4, 9, 16, 25]

// Process multiple arrays simultaneously
$a = [1, 2, 3];
$b = [4, 5, 6];
$sums = array_map(fn($x, $y) => $x + $y, $a, $b);
print_r($sums);  // [5, 7, 9]
?>

<?php
$fruits = ["orange", "apple", "banana"];
$ages   = ["Peter" => 32, "John" => 28, "Jane" => 35];

// === Sort by Value ===

sort($fruits);   // Ascending, re-indexes → ["apple","banana","orange"]
rsort($fruits);  // Descending, re-indexes → ["orange","banana","apple"]

// === Sort by Value, Preserve Keys ===

asort($ages);    // Values ascending, preserve keys → ["John"=>28,"Peter"=>32,"Jane"=>35]
arsort($ages);   // Values descending, preserve keys → ["Jane"=>35,"Peter"=>32,"John"=>28]

// === Sort by Key ===

ksort($ages);    // Keys ascending → ["Jane"=>35,"John"=>28,"Peter"=>32]
krsort($ages);   // Keys descending → ["Peter"=>32,"John"=>28,"Jane"=>35]

// === Custom Sort ===

usort($fruits, fn($a, $b) => strlen($a) <=> strlen($b));
// Sort by string length ascending
?>

<?php
$students = [
    ["name" => "Alice", "score" => 92, "city" => "New York"],
    ["name" => "Bob", "score" => 85, "city" => "Chicago"],
    ["name" => "Charlie", "score" => 78, "city" => "New York"],
];

// Access: outer first, then inner
echo $students[0]["name"];  // Alice

// Traverse
foreach ($students as $s) {
    echo "{$s['name']}: {$s['score']} points<br>";
}

// Extract a single column with array_column
$names = array_column($students, "name");
print_r($names);  // ["Alice", "Bob", "Charlie"]

$scores = array_column($students, "score", "name");
// ["Alice"=>92, "Bob"=>85, "Charlie"=>78]
// The third argument specifies which column to use as keys
?>

<?php
$products = [
    ["name" => "Keyboard", "price" => 299],
    ["name" => "Mouse", "price" => 149],
    ["name" => "Monitor", "price" => 1299],
    ["name" => "Mousepad", "price" => 29],
];

// Sort by price low to high (custom comparison function)
usort($products, fn($a, $b) => $a["price"] <=> $b["price"]);

foreach ($products as $p) {
    echo "{$p['name']}: \${$p['price']}<br>";
}
// Mousepad: $29
// Mouse: $149
// Keyboard: $299
// Monitor: $1299
?>

<?php
// Destructure an indexed array
$info = ["John", 25, "New York"];
[$name, $age, $city] = $info;
echo $name;  // John

// Destructure an associative array (PHP 7.1+)
$user = ["name" => "Jane", "age" => 22];
["name" => $n, "age" => $a] = $user;
echo $n;  // Jane

// Selective extraction (PHP 7.1+)
[2 => $city, 0 => $name] = $info;
echo $city;  // New York
?>