PHP 배열 복사 전략: 전체 복사 및 얕은 복사, 구문 분석 및 성능 비교

$original_array = ['foo' => 'bar', 'baz' => ['a' => 1, 'b' => 2]];

// 深度复制
$deep_copy = clone $original_array; // 或使用深拷贝函数如 array_map(function($value) { return clone $value; }, $original_array)

$deep_copy['foo'] = 'new_bar';
$deep_copy['baz']['a'] = 3;

var_dump($original_array); // 输出: ['foo' => 'bar', 'baz' => ['a' => 1, 'b' => 2]]
var_dump($deep_copy); // 输出: ['foo' => 'new_bar', 'baz' => ['a' => 3, 'b' => 2]]

$original_array = ['foo' => 'bar', 'baz' => ['a' => 1, 'b' => 2]];

// 浅复制
$shallow_copy = $original_array;

$shallow_copy['foo'] = 'new_bar';
$shallow_copy['baz']['a'] = 3;

var_dump($original_array); // 输出: ['foo' => 'new_bar', 'baz' => ['a' => 3, 'b' => 2]]
var_dump($shallow_copy); // 输出: ['foo' => 'new_bar', 'baz' => ['a' => 3, 'b' => 2]]

// 从数据库获取记录
$records = $db->fetchRecords();

// 深度复制记录集合以进行独立更新
$updated_records = clone $records;

function updateRecord($record) {
  $record['updated'] = true;
}

$original_record = ['id' => 1, 'name' => 'John'];

// 浅复制原始记录并更新副本
$shallow_copy = $original_record;
updateRecord($shallow_copy);

// 更新会反映在原始记录中
var_dump($original_record); // 输出: ['id' => 1, 'name' => 'John', 'updated' => true]