数组遍历 #

<?php
$fruits = ['apple', 'banana', 'cherry'];

foreach ($fruits as $fruit) {
    echo $fruit . "\n";
}

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

foreach ($user as $key => $value) {
    echo "$key: $value\n";
}

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

foreach ($numbers as &$number) {
    $number *= 2;
}
unset($number);

print_r($numbers);

<?php
$users = [
    ['name' => 'John', 'age' => 25],
    ['name' => 'Jane', 'age' => 30],
    ['name' => 'Bob', 'age' => 35]
];

foreach ($users as $user) {
    echo "{$user['name']} is {$user['age']} years old\n";
}

<?php $items = ['apple', 'banana', 'cherry']; ?>

<ul>
<?php foreach ($items as $item): ?>
    <li><?= htmlspecialchars($item) ?></li>
<?php endforeach; ?>
</ul>

<?php
$fruits = ['apple', 'banana', 'cherry'];

for ($i = 0; $i < count($fruits); $i++) {
    echo $fruits[$i] . "\n";
}

<?php
$fruits = ['apple', 'banana', 'cherry'];
$count = count($fruits);

for ($i = 0; $i < $count; $i++) {
    echo $fruits[$i] . "\n";
}

<?php
$fruits = ['apple', 'banana', 'cherry'];

for ($i = count($fruits) - 1; $i >= 0; $i--) {
    echo $fruits[$i] . "\n";
}

<?php
$numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

for ($i = 0; $i < count($numbers); $i += 2) {
    echo $numbers[$i] . "\n";
}

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

reset($user);
while (list($key, $value) = each($user)) {
    echo "$key: $value\n";
}

<?php
$fruits = ['apple', 'banana', 'cherry'];

reset($fruits);
while ($fruit = current($fruits)) {
    echo $fruit . "\n";
    next($fruits);
}

<?php
$fruits = ['apple', 'banana', 'cherry', 'date'];

echo current($fruits);
echo key($fruits);

next($fruits);
echo current($fruits);

end($fruits);
echo current($fruits);

reset($fruits);
echo current($fruits);

<?php
$fruits = ['apple', 'banana', 'cherry'];

reset($fruits);
while (key($fruits) !== null) {
    echo key($fruits) . ' => ' . current($fruits) . "\n";
    next($fruits);
}

<?php
$user = ['John', 25, 'Beijing'];

list($name, $age, $city) = $user;
echo "$name, $age, $city";

[$name, $age, $city] = $user;
echo "$name, $age, $city";

<?php
$user = ['John', 25, 'Beijing'];

list($name, , $city) = $user;
echo "$name, $city";

<?php
$data = [
    ['name' => 'John', 'age' => 25],
    ['name' => 'Jane', 'age' => 30]
];

foreach ($data as ['name' => $name, 'age' => $age]) {
    echo "$name is $age years old\n";
}

<?php
$users = [
    ['John', 25],
    ['Jane', 30],
    ['Bob', 35]
];

foreach ($users as [$name, $age]) {
    echo "$name is $age years old\n";
}

<?php
$fruits = ['apple', 'banana', 'cherry'];

$iterator = new ArrayIterator($fruits);

while ($iterator->valid()) {
    echo $iterator->key() . ' => ' . $iterator->current() . "\n";
    $iterator->next();
}

<?php
class Collection implements IteratorAggregate
{
    private array $items = [];
    
    public function add($item): void
    {
        $this->items[] = $item;
    }
    
    public function getIterator(): ArrayIterator
    {
        return new ArrayIterator($this->items);
    }
}

$collection = new Collection();
$collection->add('apple');
$collection->add('banana');

foreach ($collection as $item) {
    echo $item . "\n";
}

<?php
$names = ['John', 'Jane', 'Bob'];
$ages = [25, 30, 35];

for ($i = 0; $i < count($names); $i++) {
    echo "{$names[$i]} is {$ages[$i]} years old\n";
}

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

$squared = array_map(fn($n) => $n ** 2, $numbers);
print_r($squared);

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

array_walk($user, function($value, $key) {
    echo "$key: $value\n";
});

<?php
$fruits = ['apple', 'banana', 'cherry'];

foreach ($fruits as $index => $fruit) {
    echo ($index + 1) . ". $fruit\n";
}

<?php
$users = [
    ['name' => 'John', 'age' => 25, 'city' => 'Beijing'],
    ['name' => 'Jane', 'age' => 30, 'city' => 'Shanghai'],
    ['name' => 'Bob', 'age' => 35, 'city' => 'Guangzhou']
];
?>

<table border="1">
    <thead>
        <tr>
            <th>Name</th>
            <th>Age</th>
            <th>City</th>
        </tr>
    </thead>
    <tbody>
        <?php foreach ($users as $user): ?>
        <tr>
            <td><?= htmlspecialchars($user['name']) ?></td>
            <td><?= $user['age'] ?></td>
            <td><?= htmlspecialchars($user['city']) ?></td>
        </tr>
        <?php endforeach; ?>
    </tbody>
</table>

<?php
$menu = [
    'home' => '首页',
    'products' => '产品',
    'about' => '关于我们',
    'contact' => '联系我们'
];
?>

<nav>
    <ul>
        <?php foreach ($menu as $slug => $label): ?>
        <li>
            <a href="/<?= $slug ?>"><?= $label ?></a>
        </li>
        <?php endforeach; ?>
    </ul>
</nav>

<?php
function exportToCsv(array $data, string $filename): void
{
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename="' . $filename . '"');
    
    $output = fopen('php://output', 'w');
    
    if (!empty($data)) {
        fputcsv($output, array_keys($data[0]));
        
        foreach ($data as $row) {
            fputcsv($output, $row);
        }
    }
    
    fclose($output);
}

<?php
$items = range(1, 10000);

for ($i = 0, $count = count($items); $i < $count; $i++) {
    
}

for ($i = 0; $i < count($items); $i++) {
    
}

<?php
$items = ['a', 'b', 'c'];

foreach ($items as $item) {
    echo $item;
}

for ($i = 0; $i < count($items); $i++) {
    echo $items[$i];
}

<?php
$items = range(1, 10000);

foreach ($items as &$item) {
    $item *= 2;
}
unset($item);

foreach ($items as $key => $item) {
    $items[$key] *= 2;
}