Pet = dict:fetch(bill, Pets0), Pets1 = dict:erase(bill, Pets0), io:format("~w~n", [Pet]),

-module(remkey).
-export([start/0]).

start() ->

Pets0 = dict:from_list([{joe, cat}, {mary, turtle}, {bill, canary}]),

Pet = dict:fetch(bill, Pets0), Pets1 = dict:erase(bill, Pets0), io:format("~w~n", [Pet]),

io:format("~w~n", [dict:to_list(Pets1)]).

Pet = ets:lookup_element(Pets, bill, 2), ets:delete(Pets, bill), io:format("~w~n", [Pet]),

-module(remkey).
-export([start/0]).

start() ->

Pets = ets:new(the_map_name, [ordered_set, private, {keypos, 1}]),
ets:insert(Pets, [{joe, cat}, {mary, turtle}, {bill, canary}]),

Pet = ets:lookup_element(Pets, bill, 2), ets:delete(Pets, bill), io:format("~w~n", [Pet]),

io:format("~w~n", [ets:tab2list(Pets)]).

{value, Pet} = gb_trees:lookup(bill, Pets0), Pets1 = gb_trees:delete(bill, Pets0), io:format("~w~n", [Pet]),

-module(remkey).
-export([start/0]).

start() ->

Pets0 = gb_trees:from_orddict(lists:keysort(1, [{joe, cat}, {mary, turtle}, {bill, canary}])),

{value, Pet} = gb_trees:lookup(bill, Pets0), Pets1 = gb_trees:delete(bill, Pets0), io:format("~w~n", [Pet]),

io:format("~w~n", [gb_trees:keys(Pets1)]).