Operators

Operators that matter: comparisons, null coalescing, spaceship, and short-circuit logic.

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Arithmetic Operators

Basic arithmetic operators work as expected: +, -, *, /, %. Use parentheses to make intent clear.

<?php
$subtotal = 120;
$tax = $subtotal * 0.20;   // 24
$total = $subtotal + $tax; // 144
$remainder = 10 % 3;       // 1

Besides =, PHP supports compound assignments like +=, .= (string append), etc.

<?php
$count = 0;
$count += 1;

$message = 'Hello';
$message .= ' PHP'; // 'Hello PHP'

The most important comparisons are == vs ===. Use === (strict) to avoid surprising type juggling.

<?php
var_dump(0 == '0');   // true  (loose comparison)
var_dump(0 === '0');  // false (strict comparison)

&& and || short-circuit: PHP may not evaluate the right-hand side if the left-hand side already determines the result.

<?php
$user = null;

// Safe: if $user is null, the second part is not evaluated
if ($user !== null && $user->isAdmin) {
  echo 'Admin';
}

?? is perfect for defaults when a value may be missing (very common in request handling).

<?php
$q = $_GET['q'] ?? '';
$page = (int)($_GET['page'] ?? 1);

<=> returns -1, 0, or 1 and is useful for custom sorting.

<?php
$numbers = [3, 1, 10, 2];

usort($numbers, function ($a, $b) {
  return $a <=> $b;
});

// $numbers is now [1, 2, 3, 10]

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