erlang 去重

shijiang1130

lists:usort/1

1. 11> A=[1,1,22,3,33,22].
   
2. [1,1,22,3,33,22]
   
3. 12> lists:usort(A).
   
4. [1,3,22,33]
   
5. 13>

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patagonia2

也是用er编写的

1. -module (un).
   
2. -mode (compile).
   
3. -define (PP (V), io:format ("~s = ~p~n", [??V, V])).
   
4. 
   
5. unique (A) -> unique (A, []).
   
6. unique ([], A) -> lists:reverse (A);
   
7. unique ([H|T], A) ->
   
8.     case lists:member (H, A) of
   
9.       true -> unique (T, A);
   
10.       ____ -> unique (T, [H|A])
    
11.     end.
    
12. 
    
13. unik (L) -> unik (L, sets:new()).
    
14. unik ([], S) -> sets:to_list (S);
    
15. unik ([H|T], S) ->
    
16.     case sets:is_element (H, S) of
    
17.       true -> unik (T, S);
    
18.       ____ -> unik (T, sets:add_element (H, S))
    
19.     end.
    
20. 
    
21. main (_) ->
    
22.     L = [1, 2, 1, 3, 4, 3, 5, 5, 5, 1, 1, 1, 2, 2, 3, 3, 4, 5, 2],
    
23.     TU1 = timer:tc (fun unique/1, [L]),
    
24.     TU2 = timer:tc (fun unik/1, [L]),
    
25.     TU3 = timer:tc (fun lists:usort/1, [L]),
    
26.     ?PP (L), ?PP (TU1), ?PP (TU2), ?PP (TU3),
    
27. halt().
    

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1. L = [1,2,1,3,4,3,5,5,5,1,1,1,2,2,3,3,4,5,2]
   
2. TU1 = {5,[1,2,3,4,5]}
   
3. TU2 = {23,[3,2,5,1,4]}
   
4. TU3 = {6,[1,2,3,4,5]}
   

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shijiang1130

回复 2# patagonia2


    好奇你是怎么运行的？ main(_) .....

patagonia2

回复 3# shijiang1130

    escript file.erl

patagonia2

er语言中也有宏的概念，宏也就是宏

1. -define (Uniq(V), sets:to_list(sets:from_list(L))).
   

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很相似。