Erlang---用ETS和DETS存储数据

我的列表mylists中的reverse方法要在ETS表中使用，

-module(mylists).
-export([reverse/1]).
-export([concate/1]).
-export([flatten/1]).

reverse([],Ret) -> Ret;
reverse([H|T],Ret) ->
       Temp = [H|Ret],
       reverse(T,Temp).

reverse(L) -> reverse(L,[]).

concate([],L) -> L;
concate([H|T],L) ->
       Temp=[H|L],
       concate(T,Temp).


concate([]) -> [];
concate([H|T]) ->
 concate(reverse(H),concate(T)).
flatten(L) ->  Temp = concate(L), 
       case Temp == L of
              true -> Temp;
              false -> flatten(Temp)
       end.
创建一个ETS表，三个字母组合迭代函数，创建一些表，计算创建表所需的时间和访问表所需的时间，获胜者是.....
-module(lib_trigrams).
-export([for_each_trigram_in_the_english_language/2,timer_tests/0,time_lookup_ets_set/2,lookup_all_ets/2,time_lookup_module_sets/0,lookup_all_set/2]).
-import(mylists,[reverse/1]). 
-export([scan_word_list/3,get_next_word/2,scan_trigrams/3,make_ets_ordered_set/0,make_a_set/2,make_ets_set/0,make_mod_set/0]).
for_each_trigram_in_the_english_language(F,A0)->
   {
          
   ok,Bin0}=file:read_file("354984si.ngl.gz"),
   Bin=zlib:gunzip(Bin0),
   scan_word_list(binary_to_list(Bin),F,A0).
scan_word_list([],_,A)->
    A;
scan_word_list(L,F,A)->
    {
          
   Word,L1}=get_next_word(L,[]),
	A1=scan_trigrams([$s|Word],F,A),
	scan_word_list(L1,F,A1).
get_next_word([$
,$
|T],L)->{
          
   reverse([$s|L]),T};
get_next_word([H|T],L)->get_next_word(t,[H|L]).
scan_trigrams([X,Y,Z],F,A)->F([X,Y,Z],A);
scan_trigrams([X,Y,Z|T],F,A)->
	A1=F([X,Y,Z],F,A),
	scan_trigrams([Y,Z|T],F,A1);
scan_trigrams(_,_,A)->A.
make_ets_ordered_set()->make_a_set(ordered_set,"trigramOS.tab").
make_ets_set()->make_a_set(set,"trigrams.tab").

make_a_set(Type,FileName)->
	Tab = ets:new(table,[Type]),
	F=fun(Str,_)->ets:insert(Tab,{
          
   list_to_binary(Str)}) end,
	for_each_trigram_in_the_english_language(F,0),
	ets:tab2file(Tab,FileName),
	Size=ets:info(Tab,size),
	ets:delete(Tab),
	Size.
make_mod_set()->
	D=sets:new(),
	F=fun(Str,Set)->sets:add_element(list_to_binary(Str),Set) end,
	D1=for_each_trigram_in_the_english_language(F,D),
	file:write_file("trigrams.set",[term_to_binary(D1)]).
timer_tests()->
    time_lookup_ets_set("Ets Ordered Set","trigramsOS.tab"),
	time_lookup_ets_set("Ets set","trigramsS.tab"),
	time_lookup_module_sets().
time_lookup_ets_set(Type,File)->
    {
          
   ok,Tab}=ets:file2tab(File),
	L=ets:tab2list(Tab),
	Size=length(L),
	{
          
   M,_}=timer:tc(?MODULE,lookup_all_ets,[Tab,L]),
	io:format("~s lookup=p micro seconds~n",[Type,M/Size]),
	ets:delete(Tab).
lookup_all_ets(Tab,L)->
    lists:foreach(fun({
          
   K})->ets:lookup(Tab,K) end,L).

time_lookup_module_sets()->
    {
          
   ok,Bin} = file:read_file("trigram.set"),
	Set=binary_to_term(Bin),
	Keys=sets:to_list(Set),
	Size=length(Keys),
	{
          
   M,_}=timer:tc(?MODULE,lookup_all_set,[Set,Keys]),
	io:format("Module set lookup=~p seconds ~n",[M/Size]).
lookup_all_set(Set,L)->
    lists:foreach(fun(Key)->sets:is_element(Key,Set) end,L).

Erlang程序设计-----【瑞典】Joe Armstrong著 牛化成译—【M】北京:中国工信出版社和人民邮电出版社