将 PHP 数组转换为类变量

Posted 2023-02-24

【中文标题】将 PHP 数组转换为类变量

【英文标题】：Converting a PHP array to class variables

【发布时间】：2011-02-12 12:21:19

【问题描述】：

简单的问题，如何将关联数组转换为类中的变量？我知道有演员要做(object) $myarray 或其他任何事情，但这会创建一个新的 stdClass 并且对我没有多大帮助。是否有任何简单的一两行方法可以使我的数组中的每个 $key => $value 对变成我班级的 $key = $value 变量？我觉得为此使用 foreach 循环不是很合乎逻辑，我最好将其转换为 stdClass 并将其存储在变量中，不是吗？

class MyClass 
    var $myvar; // I want variables like this, so they can be references as $this->myvar
    function __construct($myarray) 
        // a function to put my array into variables
    

【问题讨论】：

我相信这个问题已经得到解答here。类本身内部的加载器方法似乎不是一个聪明的解决方案，因为您需要特别小心在构造函数内部抛出异常和错误处理。

【参考方案1】：

这个简单的代码应该可以工作：

<?php

  class MyClass 
    public function __construct(Array $properties=array())
      foreach($properties as $key => $value)
        $this->$key = $value;
      
    
  

?>

示例用法

$foo = new MyClass(array("hello" => "world"));
$foo->hello // => "world"

---

另外，这可能是更好的方法

<?php

  class MyClass 

    private $_data;

    public function __construct(Array $properties=array())
      $this->_data = $properties;
    

    // magic methods!
    public function __set($property, $value)
      return $this->_data[$property] = $value;
    

    public function __get($property)
      return array_key_exists($property, $this->_data)
        ? $this->_data[$property]
        : null
      ;
    
  

?>

用法一样

// init
$foo = new MyClass(array("hello" => "world"));
$foo->hello;          // => "world"

// set: this calls __set()
$foo->invader = "zim";

// get: this calls __get()
$foo->invader;       // => "zim"

// attempt to get a data[key] that isn't set
$foo->invalid;       // => null

【讨论】：

不要认为你需要 $this->$key = $value; 中的 声明

@AntonioCS，这不是必需的，但它肯定强调了对变量命名属性的访问。它还演示了当变量属性变得更复杂时，可以使用 ；例如，$this->$this->foo('bar')->do_something();

真是两个不错的解决方案。我不知道那些神奇的方法，巧妙的技巧。

+1。还应该提到，除非您确保 __get 方法返回一个引用，否则使用带有数组的魔法方法可能会导致一些小问题（即 $this->myArray[] = $value; 将不起作用）

@Tobia 在第一种方法中，是的：property_exists 只有在类代码中明确定义了属性时才会返回 true。因此，您只需像往常一样定义属性，然后在构造函数的 foreach 循环中，在分配属性之前检查if (property_exists(self::class, $key))。

【参考方案2】：

最好的解决方案是让trait 带有静态函数fromArray 可用于数据加载：

trait FromArray 
 public static function fromArray(array $data = []) 
   foreach (get_object_vars($obj = new self) as $property => $default) 
     if (!array_key_exists($property, $data)) continue;
     $obj->$property = $data[$property]; // assign value to object
   
   return $obj;
  

然后你可以像这样使用这个特性：

class Example 
  use FromArray;
  public $data;
  public $prop;

然后你可以调用静态fromArray函数来获取Example类的新实例：

$obj = Example::fromArray(['data' => 123, 'prop' => false]);
var_dump($obj);

我还有更复杂的版本，带有嵌套和值过滤https://github.com/OzzyCzech/fromArray

【讨论】：

不用get_object_vars($obj = new self，你可以直接说get_class_vars(get_class($this))——不需要创建一个虚拟对象。

@Meglio 实际上，它不是一个虚拟对象，它是设置属性后最终返回的实例。如果使用get_class($this) 或替代self::class，则必须在循环之前创建一个实例。

【参考方案3】：

如果你（像我一样）来这里寻找 array->class 的源代码生成器，我真的找不到任何源代码生成器，然后我想出了这个（正在进行的工作，没有经过很好的测试或任何东西， json_decode 返回数组。）：

<?php
declare(strict_types = 1);

$json = <<<'JSON'
"object_kind":"push","event_name":"push","before":"657dbca6668a99012952c58e8c8072d338b48d20","after":"5ac3eda70dbb44bfdf98a3db87515864036db0f9","ref":"refs/heads/master","checkout_sha":"5ac3eda70dbb44bfdf98a3db87515864036db0f9","message":null,"user_id":805411,"user_name":"hanshenrik","user_email":"[e-mail]","user_avatar":"https://secure.gravatar.com/avatar/e3af2bd4b5604b0b661b5e6646544eba?s=80\u0026d=identicon","project_id":3498684,"project":"name":"gitlab_integration_tests","description":"","web_url":"https://gitlab.com/divinity76/gitlab_integration_tests","avatar_url":null,"git_ssh_url":"[e-mail]:divinity76/gitlab_integration_tests.git","git_http_url":"https://gitlab.com/divinity76/gitlab_integration_tests.git","namespace":"divinity76","visibility_level":0,"path_with_namespace":"divinity76/gitlab_integration_tests","default_branch":"master","homepage":"https://gitlab.com/divinity76/gitlab_integration_tests","url":"[e-mail]:divinity76/gitlab_integration_tests.git","ssh_url":"[e-mail]:divinity76/gitlab_integration_tests.git","http_url":"https://gitlab.com/divinity76/gitlab_integration_tests.git","commits":["id":"5ac3eda70dbb44bfdf98a3db87515864036db0f9","message":"dsf\n","timestamp":"2017-06-14T02:21:50+02:00","url":"https://gitlab.com/divinity76/gitlab_integration_tests/commit/5ac3eda70dbb44bfdf98a3db87515864036db0f9","author":"name":"hanshenrik","email":"[e-mail]","added":[],"modified":["gitlab_callback_page.php"],"removed":[]],"total_commits_count":1,"repository":"name":"gitlab_integration_tests","url":"[e-mail]:divinity76/gitlab_integration_tests.git","description":"","homepage":"https://gitlab.com/divinity76/gitlab_integration_tests","git_http_url":"https://gitlab.com/divinity76/gitlab_integration_tests.git","git_ssh_url":"[e-mail]:divinity76/gitlab_integration_tests.git","visibility_level":0        
JSON;
$arr = json_decode ( $json, true );

var_dump ( array_to_class ( $arr ) );

/**
 *
 * @param array $arr            
 * @param string $top_class_name            
 */
function array_to_class(array $arr, string $top_class_name = "TopClass"): string 
    $top_class_name = ucfirst ( $top_class_name );
    $classes = array (); // deduplicated 'definition'=>true,array_keys();
    $internal = function (array $arr, string $top_class_name) use (&$classes, &$internal) 
        $curr = 'Class ' . $top_class_name . ' ' . "\n";
        foreach ( $arr as $key => $val ) 
            $type = gettype ( $val );
            if (is_array ( $val )) 
                $type = ucfirst ( ( string ) $key );
                $classes [$internal ( $val, ( string ) $key )] = true;
            
            $curr .= <<<FOO
    /**
     * @property $type \$$key
    */
FOO;
            $curr .= "\n    public $" . $key . ";\n";
        
        $curr .= '';
        $classes [$curr] = true;
    ;
    $internal ( $arr, $top_class_name );
    return implode ( "\n", array_keys ( $classes ) );

输出：

Class project 
    /**
     * @property string $name
    */
    public $name;
    /**
     * @property string $description
    */
    public $description;
    /**
     * @property string $web_url
    */
    public $web_url;
    /**
     * @property NULL $avatar_url
    */
    public $avatar_url;
    /**
     * @property string $git_ssh_url
    */
    public $git_ssh_url;
    /**
     * @property string $git_http_url
    */
    public $git_http_url;
    /**
     * @property string $namespace
    */
    public $namespace;
    /**
     * @property integer $visibility_level
    */
    public $visibility_level;
    /**
     * @property string $path_with_namespace
    */
    public $path_with_namespace;
    /**
     * @property string $default_branch
    */
    public $default_branch;
    /**
     * @property string $homepage
    */
    public $homepage;
    /**
     * @property string $url
    */
    public $url;
    /**
     * @property string $ssh_url
    */
    public $ssh_url;
    /**
     * @property string $http_url
    */
    public $http_url;


Class author 
    /**
     * @property string $name
    */
    public $name;
    /**
     * @property string $email
    */
    public $email;

Class added 

Class modified 
    /**
     * @property string $0
    */
    public $0;

Class removed 

Class 0 
    /**
     * @property string $id
    */
    public $id;
    /**
     * @property string $message
    */
    public $message;
    /**
     * @property string $timestamp
    */
    public $timestamp;
    /**
     * @property string $url
    */
    public $url;
    /**
     * @property Author $author
    */
    public $author;
    /**
     * @property Added $added
    */
    public $added;
    /**
     * @property Modified $modified
    */
    public $modified;
    /**
     * @property Removed $removed
    */
    public $removed;

Class commits 
    /**
     * @property 0 $0
    */
    public $0;

Class repository 
    /**
     * @property string $name
    */
    public $name;
    /**
     * @property string $url
    */
    public $url;
    /**
     * @property string $description
    */
    public $description;
    /**
     * @property string $homepage
    */
    public $homepage;
    /**
     * @property string $git_http_url
    */
    public $git_http_url;
    /**
     * @property string $git_ssh_url
    */
    public $git_ssh_url;
    /**
     * @property integer $visibility_level
    */
    public $visibility_level;

Class TopClass 
    /**
     * @property string $object_kind
    */
    public $object_kind;
    /**
     * @property string $event_name
    */
    public $event_name;
    /**
     * @property string $before
    */
    public $before;
    /**
     * @property string $after
    */
    public $after;
    /**
     * @property string $ref
    */
    public $ref;
    /**
     * @property string $checkout_sha
    */
    public $checkout_sha;
    /**
     * @property NULL $message
    */
    public $message;
    /**
     * @property integer $user_id
    */
    public $user_id;
    /**
     * @property string $user_name
    */
    public $user_name;
    /**
     * @property string $user_email
    */
    public $user_email;
    /**
     * @property string $user_avatar
    */
    public $user_avatar;
    /**
     * @property integer $project_id
    */
    public $project_id;
    /**
     * @property Project $project
    */
    public $project;
    /**
     * @property Commits $commits
    */
    public $commits;
    /**
     * @property integer $total_commits_count
    */
    public $total_commits_count;
    /**
     * @property Repository $repository
    */
    public $repository;

【参考方案4】：

这是另一个使用PDOStatement::fetchObject 的解决方案，虽然它有点小技巧。

$array = array('property1' => 'value1', 'property2' => 'value2');
$className = 'MyClass';

$pdo = new PDO('sqlite::memory:'); // we don't actually need sqlite; any PDO connection will do
$select = 'SELECT ? AS property1, ? AS property2'; // this could also be built from the array keys
$statement = $pdo->prepare($select);

// this last part can also be re-used in a loop
$statement->execute(array_values($array));
$myObject = $statement->fetchObject($className);

【参考方案5】：

定义一个静态方法来转换从数组中获取实例。最好，为它定义一个接口。这是声明性的，不会污染构造函数，允许您设置私有属性并仍然实现反射无法实现的自定义逻辑。如果您想要一个通用的解决方案，请定义一个特征并在您的类中使用它。

class Test implements ContructableFromArray 
   private $property;
   public static function fromArray(array $array) 
       $instance = new self();
       $instance->property = $array['property'];
       return $instance;
   


interface ConstructableFromArray 
   public static function fromArray(array $array);

【讨论】：

如果您的业务逻辑不需要接口，请不要创建接口。这是矫枉过正。

【参考方案6】：

如果要将嵌套数组转换为对象，请使用以下代码：

class ToObject

    private $_data;

    public function __construct(array $data)
    
        $this->setData($data);
    

    /**
     * @return array
     */
    public function getData()
    
        return $this->_data;
    

    /**
     * @param array $data
     */
    public function setData(array $data)
    
        $this->_data = $data;
        return $this;
    

    public function __call($property, $args)
    
        // NOTE: change lcfirst if you need (ucfirst/...) or put all together
        $property = lcfirst(str_replace('get', '', $property));
        if (array_key_exists($property, $this->_data)) 
            if (is_array($this->_data[$property])) 
                return new self($this->_data[$property]);
            
            return $this->_data[$property];
        
        return null;
    

那么你可以这样使用：

$array = [
    'first' => '1.1',
    'second' => [
        'first' => '2.1',
        'second' => '2.2',
        'third' => [
            'first' => '2.3.1'
        ]
    ]
];
$object = new ToObject($array);
$object->getFirst(); // returns 1.1
$object->getSecond()->getFirst(); // returns 2.1
$object->getSecond()->getData(); // returns second array
$object->getSecond()->getThird()->getFirst(); // returns 2.3.1