在 Erlang 中从多个进程中排序数据

Question

我正在制作一个程序，将 ID 号分类为房间和组。我正在尝试从多个并行进程中订购一些输出，但输出是这样的

{'C003','Group A',1}
{'C002','Group B',3}
{'C015','Group C',5}
{'C016','Group D',7}
{'C003','Group A',2}
{'C002','Group B',4}
{'C015','Group C',6}
{'C016','Group D',8}

但我想要这样：

{'C003','Group A',1}
{'C003','Group A',2}
{'C002','Group B',3}
{'C002','Group B',4}
{'C015','Group C',5}
{'C015','Group C',6}
{'C016','Group D',7}   
{'C016','Group D',8}

我想也许我可以将这些数字发送到一个进程并让它以某种方式按顺序打印它们和它们的组，但我不确定如何在进程并行发生的同时执行此操作。我认为一个解决方案可能是选择性接收，但我似乎也无法弄清楚。任何人都可以帮助我吗？ 这是我的主程序中的一个 sn-p 代码 注意：我是 Erlang 的新手

-module(ppp).

-compile([export_all]).

categorise(L) ->

     Size = len(L) div 4,
     Rem = len(L) rem 4,    
     spawn(ppp, cat, [self(), 'Group A', L, 0, Size + Rem]),
     spawn(ppp, cat, [self(), 'Group B', L, (Size + Rem), Size]),
     spawn(ppp, cat, [self(), 'Group C', L, (2*Size + Rem), Size]),
     spawn(ppp, cat, [self(), 'Group D', L, (3*Size  + Rem), Size]), 
     wait(4). 

wait(0) -> {done};
wait(N) ->
receive
    done -> wait(N-1)
end.

cat(P, Name, L, Start, Elements) ->     
     Extract = lists:split(Start, L),   
     Group = element(2, Extract),   
     AGroup = lists:sublist(Group, Elements),
     spawn(ppp, putInRoom, [P, Name, AGroup]).

putInRoom(P, _, []) -> P ! done;

putInRoom(P, GroupName, [H|T]) -> 

if GroupName == 'Group A' ->        
    io:format("~w~n", [{'C003', GroupName, H}]),        
    putInRoom(P, GroupName, T);
    GroupName == 'Group B' -> 
    io:format("~w~n", [{'C002', GroupName, H}]),
    putInRoom(P, GroupName, T);
    GroupName == 'Group C' ->
    io:format("~w~n", [{'C015', GroupName, H}]),
    putInRoom(P, GroupName, T);
    GroupName == 'Group D' ->
    io:format("~w~n", [{'C016', GroupName, H}]),
    putInRoom(P, GroupName, T)
end.

len(L) -> 
    count(L, 0).

count([], Acc) -> Acc;

count([_|T], Acc) -> count(T, Acc + 1).

Answer 1

不是为每个组生成putInRoom 进程，而是为组中的每个元素生成。

-module(ppp).

-compile([export_all]).

categorise(L) ->

     Size = len(L) div 4,
     Rem = len(L) rem 4,    
     spawn(ppp, cat, [self(), 'Group A', L, 0, Size + Rem]),
     spawn(ppp, cat, [self(), 'Group B', L, (Size + Rem), Size]),
     spawn(ppp, cat, [self(), 'Group C', L, (2*Size + Rem), Size]),
     spawn(ppp, cat, [self(), 'Group D', L, (3*Size  + Rem), Size]), 
     wait(4). 

wait(0) -> {done};
wait(N) ->
receive
    done -> wait(N-1)
after 2000 ->
     ok
end.

cat(P, Name, L, Start, Elements) ->
     % io:format("cat: ~p L: ~p~n", [P,L]),     
     Extract = lists:split(Start, L),   
     Group = element(2, Extract),   
     AGroup = lists:sublist(Group, Elements),
     % io:format("AGroup: ~p~n", [AGroup]),
     lists:map(fun(G) ->
                 spawn(ppp, putInRoom, [P, Name, G])
               end, AGroup).

putInRoom(P, GroupName, H) -> 
    % io:format("putInRoom: ~p, List: ~p~n", [GroupName, H]),
    if GroupName == 'Group A' ->        
        io:format("~w~n", [{'C003', GroupName, H}]);
        GroupName == 'Group B' -> 
        io:format("~w~n", [{'C002', GroupName, H}]);
        GroupName == 'Group C' ->
        io:format("~w~n", [{'C015', GroupName, H}]);
        GroupName == 'Group D' ->
        io:format("~w~n", [{'C016', GroupName, H}])
    end,
    P ! done.

len(L) -> 
    count(L, 0).

count([], Acc) -> Acc;

count([_|T], Acc) -> count(T, Acc + 1).

它按顺序打印组。

2> ppp:categorise(lists:seq(1,8)).
{'C003','Group A',1}
{'C003','Group A',2}
{'C002','Group B',3}
{'C002','Group B',4}
{'C015','Group C',5}
{'C015','Group C',6}
{'C016','Group D',7}
{'C016','Group D',8}
{done}

在产生cat 进程之间添加timer:sleep(100) 使用延迟。但是你有点放松并发的性质。所以如果你想按顺序打印消息，你必须想出一个不同的算法。

-module(ppp).

-compile([export_all]).

categorise(L) ->

     Size = len(L) div 4,
     Rem = len(L) rem 4,    
     spawn(ppp, cat, [self(), 'Group A', L, 0, Size + Rem]),
     timer:sleep(100),
     spawn(ppp, cat, [self(), 'Group B', L, (Size + Rem), Size]),
     timer:sleep(100),
     spawn(ppp, cat, [self(), 'Group C', L, (2*Size + Rem), Size]),
     timer:sleep(100),
     spawn(ppp, cat, [self(), 'Group D', L, (3*Size  + Rem), Size]), 
     wait(4). 

wait(0) -> {done};
wait(N) ->
receive
    done -> wait(N-1)
after 2000 ->
     ok
end.

cat(P, Name, L, Start, Elements) ->
     % io:format("cat: ~p L: ~p~n", [P,L]),     
     Extract = lists:split(Start, L),   
     Group = element(2, Extract),   
     AGroup = lists:sublist(Group, Elements),
     % io:format("AGroup: ~p~n", [AGroup]),
     Pid = spawn(fun putInRoom2/0),
     Pid ! {P, cat, {Name, AGroup}}.

putInRoom2() -> 
    receive
        {P, cat, {_GroupName, []}} -> P ! done;
        {P, cat, {GroupName, L}} ->
            F = fun(G, [H|T]) ->
                    if
                        GroupName == 'Group A' ->        
                            io:format("~w~n", [{'C003', GroupName, H}]);
                        GroupName == 'Group B' -> 
                            io:format("~w~n", [{'C002', GroupName, H}]);
                        GroupName == 'Group C' ->
                            io:format("~w~n", [{'C015', GroupName, H}]);
                        GroupName == 'Group D' ->
                            io:format("~w~n", [{'C016', GroupName, H}])
                    end,
                    self() ! {P, cat, {G, T}}
                end,
            F(GroupName, L),
            putInRoom2()
    end.

len(L) -> 
    count(L, 0).

count([], Acc) -> Acc;

count([_|T], Acc) -> count(T, Acc + 1).