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-rw-r--r--lib/stdlib/src/maps.erl11
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/stdlib/src/maps.erl b/lib/stdlib/src/maps.erl
index 4ef1638e6d..b8b284db65 100644
--- a/lib/stdlib/src/maps.erl
+++ b/lib/stdlib/src/maps.erl
@@ -24,6 +24,7 @@
map/2,
size/1,
without/2,
+ only/2,
get/3
]).
@@ -201,3 +202,13 @@ size(Map) when is_map(Map) ->
without(Ks, M) when is_list(Ks), is_map(M) ->
maps:from_list([{K,V}||{K,V} <- maps:to_list(M), not lists:member(K, Ks)]).
+
+
+-spec only(Ks, Map1) -> Map2 when
+ Ks :: [K],
+ Map1 :: map(),
+ Map2 :: map(),
+ K :: term().
+
+only(Ks, M) when is_list(Ks), is_map(M) ->
+ maps:from_list([{K,V}||{K,V} <- maps:to_list(M), lists:member(K, Ks)]).