erlang 常用函数

消重算饭

1> List = [1,2,3,1,2,4].

[1,2,3,1,2,4]

2> sets:to_list(sets:from_list(List)).

[3,2,1,4]

排序算法

3>lists:sort(List).

[1,1,2,2,3,4]

根据某一元素排序

4>rd(app{id,date,pkg_name,appname,version,user_num,new_user_num,used_num,los,sum_user}).

app

5> Sort = fun (A,B)-> A#app.date =< B#app.date end.                           

#Fun<erl_eval.12.113037538>

6> lists:sort(Sort, D).%按记录中的date字段进行排列

[#app{                       

     id = {app_id,{2010,7,1},<<"Packagename">>},

     date = {2010,7,1},

     pkg_name = <<"Packagename">>,appname = <<"Appname">>,

     version = <<"Version">>,user_num = 1,new_user_num = 1,

     used_num = 1,los = 7223,sum_user = 2}... ...