Loops

<?php
// for — classic counter loop
for ($i = 0; $i < 5; $i++) {
    echo $i;
}

// foreach — iterate arrays (most common)
$skills = ['Node.js', 'PHP', 'Redis'];
foreach ($skills as $i => $skill) {
    echo "$i: $skill\n";
}

// Associative array foreach
$user = ['name' => 'Nishu', 'role' => 'dev'];
foreach ($user as $key => $val) {
    echo "$key → $val\n";
}

// while
$n = 10;
while ($n > 0) {
    echo $n;
    $n -= 2;
}

// Generator — O(1) memory for large ranges
function bigRange($start, $end) {
    for ($i = $start; $i <= $end; $i++) {
        yield $i;
    }
}
foreach (bigRange(1, 1000000) as $num) {
    // Uses O(1) memory vs range(1, 1000000)
}