为什么实现ArrayAccess，Iterator和Countable的类不能与array_filter（）一起使用？

Question

我有以下类：

<?php 

/* 
* Abstract class that, when subclassed, allows an instance to be used as an array. 
* Interfaces `Countable` and `Iterator` are necessary for functionality such as `foreach` 
*/ 
abstract class AArray implements ArrayAccess, Iterator, Countable 
{ 
    private $container = array(); 

    public function offsetSet($offset, $value) 
    { 
     if (is_null($offset)) { 
      $this->container[] = $value; 
     } else { 
      $this->container[$offset] = $value; 
     } 
    } 

    public function offsetExists($offset) 
    { 
     return isset($this->container[$offset]); 
    } 

    public function offsetUnset($offset) 
    { 
     unset($this->container[$offset]); 
    } 

    public function offsetGet($offset) 
    { 
     return isset($this->container[$offset]) ? $this->container[$offset] : null; 
    } 

    public function rewind() { 
      reset($this->container); 
    } 

    public function current() { 
      return current($this->container); 
    } 

    public function key() { 
      return key($this->container); 
    } 

    public function next() { 
      return next($this->container); 
    } 

    public function valid() { 
      return $this->current() !== false; 
    } 

    public function count() { 
    return count($this->container); 
    } 

} 

?> 

然后，我有另一个类的子类AArray：

<?php 

require_once 'AArray.inc'; 

class GalleryCollection extends AArray { } 

?> 

当我填写了数据的GalleryCollection实例，然后尝试在array_filter()使用它，在第一个参数中，我收到以下错误：

Warning: array_filter() [function.array-filter]: The first argument should be an array in 

谢谢！

Answer 1

因为array_filter只适用于数组。

查看其他选项，如FilterIterator，或者先从您的对象中创建一个数组。