Get N random elements from a list

get_random

#!/usr/bin/env escript

main([NS, SL]) ->
    try
        N = list_to_integer(NS),
        List = eval(SL),
        io:format("Result: ~p~n", [random(List,N)])
    catch
        _:_ ->
            usage()
    end;
main(Input) ->
    io:format("Input: ~p~n", [Input]),
    usage().

usage() ->
    io:format("usage: random N [ele1,ele2,ele3,ele4]\n"),
    halt(1).

random(L, N) ->
    random(list_to_tuple(L), N, []).

random({},_,Acc) ->
    Acc;
random(_,0,Acc) ->
    Acc;
random(T, N, Acc) ->
    {A1,A2,A3} = os:timestamp(),
    random:seed(A1, A2, A3),
    Rand = random:uniform(size(T)),
    E = erlang:element(Rand, T),
    random(delete_element(Rand, T), N-1, Acc ++ [E]).

delete_element(N,T) -> %% change for erlang:delete_element
    L = erlang:tuple_to_list(T),
    Ele = erlang:element(N, T),
    erlang:list_to_tuple(lists:filter(fun(X) -> X =/= Ele end, L)). %%BUG when exits duplicate elements

eval(S) ->
    Last = lists:last(S),
    if 
        Last =/= 46 ->
            eval(S ++ ".",[]);
        true ->
            eval(S,[])
    end.
eval(S,Environ) ->
    {ok,Scanned,_} = erl_scan:string(S),
    {ok,Parsed} = erl_parse:parse_exprs(Scanned),
    {value, R, _} = erl_eval:exprs(Parsed,Environ),
    R.