Arrays 值为数组的Oracle pl/sql映射

我需要创建关联数组，其中键是VARCHAR（20），值是VARCHAR数组。 例如：

customer_by_locations: {
   "London": {
               "John Doe", "Samantha Simpson", "Nicolas Darcula"
             },
   "Stambul": {
               "Abdula Ibn Rahim", "Another Abdula"
             }
}

我已创建查询：

declare 
  type customers is varray(10) of varchar2(20);
  type locations is table of customers index by varchar2(20);

  list_locations locations;
  list_customers varchar(20);
begin
  list_locations('London') := ("John Doe", "Samantha Simpson", "Nicolas Darcula");
  list_locations('Stambul') := ("Abdula Ibn Rahim", "Another Abdula");

  for i in 1 .. list_locations loop
    DBMS_OUTPUT.PUT_LINE('Total ' || list_locations(i));   
    //Something do 
  end loop;  
end; 

但我有错误

PLS-00382：表达式类型错误

---

请告诉我，我将如何在oracle pl/sql中将数组声明为值并在其中赋值。

您是否尝试过：

list_locations（'London'）：=“John Doe”、“Samantha Simpson”、“Nicolas Darcula”？是的，我试过这个。同样的错误。哦，我认为你的循环是错误的。。。你不能从1路去伦敦。你想要这个：
用于1中的i。。列出位置。计数循环
参见此处示例：感谢您的回复。我真的忘记了数组计数。是的。这是工作。非常感谢您的回复。我真的很感谢你的帮助。
declare 
  type customers is varray(10) of varchar2(20);
  type locations is table of customers index by varchar2(20);

  list_locations locations;
  list_customers varchar(20);
  v_location varchar2(20);
begin
  list_locations('London') := customers('John Doe', 'Samantha Simpson', 'Nicolas Darcula');
  list_locations('Stambul') := customers('Abdula Ibn Rahim', 'Another Abdula');

  v_location := list_locations.first;
  loop
    exit when v_location is null;

    for i in 1 .. list_locations(v_location).count loop
      dbms_output.put_line(v_location||': '||list_locations(v_location)(i));
    end loop;

    v_location := list_locations.next(v_location);
  end loop;
end; 
/