How do array_map(), array_filter(), and array_reduce() work?

These are functional-style tools that work with arrays:

🔸 array_map()

• Applies a callback to each element, returning a new array.

$nums = [1, 2, 3];
$squared = array_map(fn($n) => $n * $n, $nums);
// [1, 4, 9]

🔸 array_filter()

• Filters elements based on a condition, keeping those that return true.

$nums = [1, 2, 3, 4];
$even = array_filter($nums, fn($n) => $n % 2 == 0);
// [2, 4]

🔸 array_reduce()

• Reduces an array to a single value using a callback.

$nums = [1, 2, 3];
$sum = array_reduce($nums, fn($carry, $item) => $carry + $item, 0);
// 6

📌 Interview Tip: Be ready to use these for clean, concise logic — like filtering user input, transforming arrays, or computing totals.

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