public static function categoryList()
    {
        $data = self::find()->orderBy('category')->groupBy(['category'])->select(['category'])->column();
        return array_combine($data, $data);
    }
public static function categoryList()
    {
        $data = self::find()->orderBy('category')->groupBy(['category'])->select(['category'])->column();
        return array_combine($data, $data);
    }
public static function categoryList ( ) { $ data = self :: find ( ) -> orderBy ( 'category' ) -> groupBy ( [ 'category' ] ) -> select ( [ 'category' ] ) -> column ( ) ; return array_combine ( $ data , $ data ) ; }
Gets all used categories list.
@return array source category list
Gets all used categories list .