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PHP. Is it possible to use array_column with an array of objects（5个答案）
三年前就关门了。
在使用Yii1框架和PHP 5.6.40的生产环境中，array_column函数返回的是一个空数组。
这个数组是一个CActiveRecord的列表，它来自另一个CActiveRecord的HAS_MANY关系。在我的本地机器（PHP 7.1.23）上，array_column函数可以正常工作。除非我误解了，否则documentation说明array_column在PHP 5.6.40中是可用的。

/**
 * This is the model class for table 'my_active_record'.
 *
 * The following are the available columns in table 'my_active_record':
 * @property integer $id
 *
 * The following are the available model relations:
 * @property RelatedActiveRecord[] $relatedActiveRecords
 */
class MyActiveRecord extends CActiveRecord
{
    public function relations()
    {
        return array(
            'relatedActiveRecords' => array(self::HAS_MANY, 'related_active_records', 'my_active_record_id')
        );
    }
}

/**
 * This is the model class for table 'related_active_record'.
 *
 * The following are the available columns in table 'related_active_record':
 * @property integer $id
 * @property integer $my_active_record_id
 *
 * The following are the available model relations:
 * @property MyActiveRecord $myActiveRecord
 */
class MyActiveRecord extends CActiveRecord
{
    public function relations()
    {
        return array(
            'myActiveRecord' => array(self::BELONGS_TO, 'my_active_record', 'my_active_record_id')
        );
    }
}

$myActiveRecord = new MyActiveRecord();
print_r(array_column($myActiveRecord->relatedActiveRecords, 'id'));

预期结果：Array ( [0] => 1 [1] => 2 [2] => 3 )实际结果：Array ( ).个