yii\base\Model::activeAttributes PHP Method

    public function activeAttributes()
    {
        $scenario = $this->getScenario();
        $scenarios = $this->scenarios();
        if (!isset($scenarios[$scenario])) {
            return [];
        }
        $attributes = $scenarios[$scenario];
        foreach ($attributes as $i => $attribute) {
            if ($attribute[0] === '!') {
                $attributes[$i] = substr($attribute, 1);
            }
        }
        return $attributes;
    }