Erlang ETS Match

Question

with Erlang ets, how can Match part of key?

for exmaple, ets:insert(time_tb,{ {un_known,{<<"knonw_1">>,<<"knonw_2">>} },[data]}).

the key was {un_known,{<<"knonw_1">>,<<"knonw_2">>}

How can I match from the table if I only knows {<<"knonw_1">>,<<"knonw_2">>} is this possible?

Answer 1

If I understood correctly,no necessary use function match. You can do this with functions ets:select and est:fun2ms for simplify match specifications.

R=ets:fun2ms(fun(Data={{_,T},_}) when T =:= {<<"knonw_1">>,<<"knonw_2">>}->Data end).
ets:select(time_tb,R).

and get:

[{{un_known,{<<"knonw_1">>,<<"knonw_2">>}},[data]}]