在Erlang中操作复杂列表

我在Erlang有这个列表

[{title,
"ad"},
{description,
"fdf"},
{allow_change_subj,
true},
{allow_query_users,
true},
{allow_private_messages,
true},
{allow_private_messages_from_visitors,
anyone},
{allow_visitor_status,
true},
{allow_visitor_nickchange,
true},
{public,
true},
{public_list,
true},
{persistent,
true},
{moderated,
true},
{members_by_default,
true},
{members_only,
false},
{allow_user_invites,
true},
{password_protected,
false},
{captcha_protected,
false},
{password,
[]},
{anonymous,
true},
{logging,
false},
{max_users,
200},
{allow_voice_requests,
true},
{voice_request_min_interval,
1800},
[{captcha_whitelist, []}, 
{affiliations, [{{"test1", "serverdomain.com", []},{owner,[]}}]}, {{"testuser4_gmail.com", "serverdomain.com", []},    {member, []}}],
{subject,
[]},
{subject_author,
[]}]]

我正在尝试获取关键“从属关系”下的用户名（test1，testuser4_gmail.com），但从该列表中获取用户名时遇到问题

在此方面的任何帮助都将不胜感激

更新：

我很好地得到了'宣誓'的关键和它下的一切，但在我所寻找的问题。我提供一个例子

 ->   Listt = [{captcha_whitelist, []}, {affiliations, [{{"test1", "54.69.16.10", []},{owner,[]}}]}].
    
  ->  lists:keyfind('affiliations',1, Listt).
  Output : {affiliations,[{{"test1","54.69.16.10",[]},{owner,[]}}]}

---

Target:获取诸如“test1”之类的值，以及更多（如果有的话）诸如“test1”、“testuser4\u gmail.com”

根据您的代码示例，下面是一些可以进一步提取的方法

以下是您的代码示例结构：

1> Listt = [{captcha_whitelist, []}, {affiliations, [{{"test1", "54.69.16.10", []},{owner,[]}}]}].
[{captcha_whitelist,[]},
 {affiliations,[{{"test1","54.69.16.10",[]},{owner,[]}}]}]

3> Users = lists:map(fun({User, Role}) -> User end, Affiliations).
[{"test1","54.69.16.10",[]}]

我将使用PropList提取第一级：

2> Affiliations =  proplists:get_value(affiliations,Listt).
[{{"test1","54.69.16.10",[]},{owner,[]}}]

列表：映射/2

和模式匹配可以帮助您仅使用结构的第一部分转换列表：

1> Listt = [{captcha_whitelist, []}, {affiliations, [{{"test1", "54.69.16.10", []},{owner,[]}}]}].
[{captcha_whitelist,[]},
 {affiliations,[{{"test1","54.69.16.10",[]},{owner,[]}}]}]

3> Users = lists:map(fun({User, Role}) -> User end, Affiliations).
[{"test1","54.69.16.10",[]}]

如果要进一步提取，可以执行以下操作：

4> lists:map(fun({Username, Server, _}) -> Username end, User). 
["test1"]

或者，您甚至可以同时执行步骤3和步骤4，并获得用户列表：

5> lists:map(fun({{User, Server, _}, Role}) -> User end, Affiliations).       
["test1"]

---

也许你应该展示一下你第一次尝试的代码？我只是想了解你的合作关系，但不知道如何前进。我提供它作为有问题的更新。有什么问题吗？输出看起来是正确的，好像你们并没有读过这个问题，只是更新了一下