赋值运算符 #

<?php
$name = "PHP";
$version = 8.2;
$isActive = true;
$items = [1, 2, 3];

<?php
$a = $b = $c = 0;
echo $a, $b, $c;

<?php
$sum = 1 + 2 + 3;
$message = "Hello" . " " . "World";
$result = max(1, 2, 3);

<?php
$a = 10;
$a += 5;
echo $a;

$a -= 3;
echo $a;

$a *= 2;
echo $a;

$a /= 4;
echo $a;

$a %= 3;
echo $a;

$a **= 2;
echo $a;

<?php
$message = "Hello";
$message .= " ";
$message .= "World";
echo $message;

<?php
$arr = ['a' => 1];
$arr += ['b' => 2, 'a' => 10];
print_r($arr);

<?php
$a = 10;
$b = &$a;

$a = 20;
echo $b;

$b = 30;
echo $a;

<?php
function &getReference(): int
{
    static $value = 0;
    return $value;
}

$ref = &getReference();
$ref = 10;
echo getReference();

<?php
$arr = [1, 2, 3];
$ref = &$arr[0];
$ref = 100;
print_r($arr);

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

foreach ($arr as &$value) {
    $value *= 2;
}
unset($value);

print_r($arr);

<?php
$a = null;
$b = $a ?? "default";
echo $b;

$a = "value";
$b = $a ?? "default";
echo $b;

<?php
$a = null;
$a ??= "default";
echo $a;

$a ??= "another";
echo $a;

<?php
function process(array $config): void
{
    $config['timeout'] ??= 30;
    $config['retries'] ??= 3;
    $config['debug'] ??= false;
    
    print_r($config);
}

process(['timeout' => 60]);

<?php
$a = 0;
$b = $a ?? "default";
$c = $a ?: "default";
echo "b = $b, c = $c";

$a = null;
$b = $a ?? "default";
$c = $a ?: "default";
echo "b = $b, c = $c";

<?php
$result = $condition ? $valueIfTrue : $valueIfFalse;

$age = 20;
$status = $age >= 18 ? "成年" : "未成年";
echo $status;

<?php
$score = 85;
$grade = $score >= 90 ? "A" : 
         ($score >= 80 ? "B" : 
         ($score >= 70 ? "C" : 
         ($score >= 60 ? "D" : "F")));
echo $grade;

<?php
$name = "";
$displayName = $name ?: "Guest";
echo $displayName;

$name = "John";
$displayName = $name ?: "Guest";
echo $displayName;

<?php
$name = "0";
$displayName = $name ?: "Guest";
echo $displayName;

$name = "0";
$displayName = $name !== "" ? $name : "Guest";
echo $displayName;

<?php
$a = 5;
$a &= 3;
echo $a;

$a = 5;
$a |= 3;
echo $a;

$a = 5;
$a ^= 3;
echo $a;

$a = 5;
$a <<= 1;
echo $a;

$a = 5;
$a >>= 1;
echo $a;

<?php
$a = 5;
if ($a = 10) {
    echo "总是执行";
}

<?php
$a = 5;
if ($a === 10) {
    echo "a等于10";
}

<?php
if (10 === $a) {
    
}

<?php
$arr = [1, 2, 3];
list($a, $b, $c) = $arr;
echo "$a, $b, $c";

[$a, $b, $c] = $arr;
echo "$a, $b, $c";

<?php
$arr = [1, 2, 3, 4];
[$a, , $c] = $arr;
echo "$a, $c";

<?php
$user = ['name' => 'John', 'age' => 25];
['name' => $name, 'age' => $age] = $user;
echo "$name, $age";

<?php
$data = [
    'user' => ['name' => 'John', 'email' => 'john@example.com'],
    'status' => 'active'
];

['user' => ['name' => $name], 'status' => $status] = $data;
echo "$name, $status";

<?php
$count = 0;
$name = "";
$items = [];
$active = false;

<?php
$name = $_GET['name'] ?? 'Guest';
$page = $_GET['page'] ?? 1;

<?php
$isValid = $user !== null && $user->isActive();
$hasPermission = $user->can('edit') || $user->isAdmin();

if ($isValid && $hasPermission) {
    
}

<?php
function getUser(): array
{
    return ['name' => 'John', 'age' => 25];
}

['name' => $name, 'age' => $age] = getUser();