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-rw-r--r--lib/stdlib/src/maps.erl16
1 files changed, 15 insertions, 1 deletions
diff --git a/lib/stdlib/src/maps.erl b/lib/stdlib/src/maps.erl
index 3877c150ec..2913a2ff86 100644
--- a/lib/stdlib/src/maps.erl
+++ b/lib/stdlib/src/maps.erl
@@ -19,7 +19,8 @@
-module(maps).
--export([get/3,fold/3, map/2, size/1,
+-export([get/3,filter/2,fold/3, map/2,
+ size/1,
without/2, with/2]).
@@ -145,6 +146,19 @@ get(Key,Map,Default) ->
erlang:error({badmap,Map},[Key,Map,Default]).
+-spec filter(Pred,Map1) -> Map2 when
+ Pred :: fun((Key, Value) -> boolean()),
+ Key :: term(),
+ Value :: term(),
+ Map1 :: map(),
+ Map2 :: map().
+
+filter(Pred,Map) when is_function(Pred,2), is_map(Map) ->
+ maps:from_list([{K,V}||{K,V}<-maps:to_list(Map),Pred(K,V)]);
+filter(Pred,Map) ->
+ erlang:error(error_type(Map),[Pred,Map]).
+
+
-spec fold(Fun,Init,Map) -> Acc when
Fun :: fun((K, V, AccIn) -> AccOut),
Init :: term(),