មូលដ្ឋាន PHP: Arrays + Loops + Array Functions

<?php
$fruits = ["Apple", "Banana", "Mango", "Orange"];
echo $fruits[0]; // Apple (index 0)
echo $fruits[2]; // Mango (index 2)

// Update
$fruits[1] = "Strawberry";

// Add element
$fruits[] = "Grape";

echo count($fruits); // 5
?>

<?php
$colors = ["Red", "Green", "Blue"];
array_push($colors, "Yellow");    // Add to end
$removed = array_pop($colors);    // Remove from end
array_unshift($colors, "White");  // Add to start
$first = array_shift($colors);    // Remove from start
print_r($colors);
?>

<?php
$scores = [85, 92, 78, 65, 95];

// for loop
for ($i = 0; $i < count($scores); $i++) {
    echo "Index $i: $scores[$i]\n";
}

// foreach loop
foreach ($scores as $score) {
    echo "Score: $score\n";
}

// foreach with index
foreach ($scores as $index => $score) {
    echo "[$index] => $score\n";
}
?>

<?php
$student = [
    "name"  => "Sokha",
    "age"   => 20,
    "major" => "IT",
    "score" => 85
];

echo $student["name"];  // Sokha
echo $student["score"]; // 85

// Update
$student["score"] = 90;

// Add new key
$student["email"] = "sokha@mail.com";
?>

<?php
$product = ["name"=>"Laptop","price"=>850,"brand"=>"ASUS","stock"=>15];
foreach ($product as $key => $value) {
    echo "$key: $value\n";
}
?>

<?php
$students = [
    ["name"=>"Sokha",   "age"=>20, "score"=>85],
    ["name"=>"Dara",    "age"=>21, "score"=>92],
    ["name"=>"Vichetra","age"=>19, "score"=>78],
];
// Access:
echo $students[0]["name"];  // Sokha
echo $students[1]["score"]; // 92
?>

<?php
foreach ($students as $row) {
    echo "<tr>";
    foreach ($row as $key => $val) {
        echo "<td>$val</td>";
    }
    echo "</tr>";
}
?>

<?php
$cities = ["Phnom Penh", "Siem Reap", "Battambang", "Sihanoukville"];
for ($i = 0; $i < count($cities); $i++) {
    echo ($i + 1) . ". " . $cities[$i] . "\n";
}
?>

<?php
// Indexed
$fruits = ["Apple", "Banana", "Mango"];
foreach ($fruits as $fruit) {
    echo "Fruit: $fruit\n";
}
// Associative
$person = ["name"=>"Dara", "age"=>21, "city"=>"Phnom Penh"];
foreach ($person as $key => $value) {
    echo "$key: $value\n";
}
?>

<?php
$matrix = [[1,2,3],[4,5,6],[7,8,9]];
foreach ($matrix as $rowIndex => $row) {
    echo "Row $rowIndex: ";
    foreach ($row as $val) {
        echo "$val ";
    }
    echo "\n";
}
?>

<?php
$scores = [85, 92, 45, 78, 30, 95, 60];

// continue: skip scores below 50
echo "Passing scores:\n";
foreach ($scores as $s) {
    if ($s < 50) continue;
    echo "$s ";
}

// break: stop at first failing score
echo "\nScores until first fail:\n";
foreach ($scores as $s) {
    if ($s < 50) break;
    echo "$s ";
}
?>

<?php
$arr = [10, 20, 30];
array_push($arr, 40);       // [10,20,30,40]
$last = array_pop($arr);    // [10,20,30] removed=40
array_unshift($arr, 5);     // [5,10,20,30]
$first = array_shift($arr); // [10,20,30] removed=5
?>

<?php
$fruits = ["Apple", "Banana", "Mango", "Orange"];
var_dump(in_array("Mango", $fruits));   // true
var_dump(in_array("Grape", $fruits));   // false
$pos = array_search("Orange", $fruits); // 3
?>

<?php
$nums = [30, 10, 50, 20, 40];
sort($nums);   // [10,20,30,40,50]
rsort($nums);  // [50,40,30,20,10]

$ages = ["Sokha"=>20, "Dara"=>18, "Neary"=>22];
asort($ages);  // sort by value, keep keys
ksort($ages);  // sort by key
?>

<?php
$nums = [10, 20, 30, 20, 10, 40];
echo count($nums);                  // 6
echo array_sum($nums);              // 130
print_r(array_unique($nums));       // [10,20,30,40]
print_r(array_merge([1,2],[3,4]));  // [1,2,3,4]

$p = ["name"=>"Dara","age"=>21];
print_r(array_keys($p));    // ["name","age"]
print_r(array_values($p));  // ["Dara",21]

echo implode(" - ", ["A","B","C"]); // A - B - C
$parts = explode(",", "PHP,JS,Python");
?>