I propose you this solution:
[edit]
I modified the code to answer your last comment, there are still fuzzy things:
- if Assets are different, creates different record list?
- if not what should be done with Asset name? I have chosen to keep the "smallest one"
- is the order of records important - I decided no
One remark, I am missing some context, but If I add to collect such informations, I would store it in an ets table. It is faster to update, easy to traverse, and easy to transform into list if needed.
-module (t).
-compile([export_all]).
% rec = {atom,term}
% reclist = [rec,...]
% asset = {bin,reclist}
% eval_data = [{list,asset}]
% eval_set = [eval_data,...]
% recs = {atom,[term]}
% recslist = [recs,...]
addrec({Key,Val},Recslist) ->
Val_list = proplists:get_value(Key, Recslist, []),
[{Key,[Val|Val_list]}|proplists:delete(Key,Recslist)].
merge_rec(Reclist,Recslist) -> lists:foldl(fun(Rec,Acc) -> addrec(Rec,Acc) end,Recslist,Reclist).
merge_eval([{Eval,{Asset,Reclist}}],[]) ->
[{Eval,{Asset,[{Key,[Val]} || {Key,Val} <- Reclist]}}];
merge_eval([{Eval,{Asset,Reclist}}],[{Eval_low,{Asset_low,Recslist}}]) ->
[{min(Eval,Eval_low),{min(Asset,Asset_low),merge_rec(Reclist,Recslist)}}].
merge_set(Eval_set) -> lists:foldl(fun(Eval_data,Acc) -> merge_eval(Eval_data,Acc) end,[],Eval_set).
test() ->
Eval_set = [[{"eval_data_10",
{<<"prvl_mobable_asset_0000_h200401">>,
[{'F_01_0100',[1]},
{'F_01_0090',["3"]},
{'F_01_0080',[]},
{'F_01_0070',[9999]},
{'F_01_0060',[{era,0},{year,[]},{month,[]}]},
{'F_01_0050',[]},
{'F_01_0040',[]},
{'F_01_0030',[]},
{'F_01_0020',<<>>},
{'F_01_0010',<<"4 - 8">>}]}}],
[{"eval_data_11",
{<<"prvl_mobable_asset_0000_h200401">>,
[{'F_01_0100',[]},
{'F_01_0090',["2"]},
{'F_01_0080',[]},
{'F_01_0070',[22222]},
{'F_01_0060',[{era,0},{year,[]},{month,[]}]},
{'F_01_0050',[]},
{'F_01_0040',[]},
{'F_01_0030',[]},
{'F_01_0020',<<>>},
{'F_01_0010',<<"4 - 1">>}]}}]],
merge_set(Eval_set).