Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Browse files

Merge branch 'maint'

  • Loading branch information...
commit 7fd1f9be22e8b5fea2c8363770f7dba1a14f81d4 2 parents 49edd01 + f717cdd
@gustehn gustehn authored
View
BIN  bootstrap/lib/stdlib/ebin/lists.beam
Binary file not shown
View
2  lib/et/doc/src/et_desc.xmlsrc
@@ -150,7 +150,7 @@
NewEvent = #event{}]]></code>
<p>The interface of the filter function is the same as the the
- filter functions for the good old <c>lists:zf/2</c>. If the filter
+ filter functions for the good old <c>lists:filtermap/2</c>. If the filter
returns <c>false</c> it means that the trace data should silently
be dropped. <c>true</c> means that the trace data data already is
an <c>Event Record</c> and that it should be kept as it is.
View
25 lib/stdlib/doc/src/lists.xml
@@ -152,6 +152,31 @@
</desc>
</func>
<func>
+ <name name="filtermap" arity="2"/>
+ <fsummary>Filter and map elements which satisfy a function</fsummary>
+ <desc>
+ <p>Calls <c><anno>Fun</anno>(<anno>Elem</anno>)</c> on successive elements <c>Elem</c>
+ of <c><anno>List1</anno></c>. <c><anno>Fun</anno>/2</c> must return either a boolean
+ or a tuple <c>{true, <anno>Value</anno>}</c>. The function returns the list of elements
+ for which <c><anno>Fun</anno></c> returns a new value, where a value of <c>true</c>
+ is synonymous with <c>{true, <anno>Elem</anno>}</c>.</p>
+ <p>That is, <c>filtermap</c> behaves as if it had been defined as follows:</p>
+ <code type="none">
+filtermap(Fun, List1) ->
+ lists:foldr(fun(Elem, Acc) ->
+ case Fun(Elem) of
+ false -> Acc;
+ true -> [Elem|Acc];
+ {true,Value} -> [Value|Acc]
+ end,
+ end, [], List1).</code>
+ <p>Example:</p>
+ <pre>
+> <input>lists:filtermap(fun(X) -> case X rem 2 of 0 -> {true, X div 2}; _ -> false end end, [1,2,3,4,5]).</input>
+[1,2]</pre>
+ </desc>
+ </func>
+ <func>
<name name="flatlength" arity="1"/>
<fsummary>Length of flattened deep list</fsummary>
<desc>
View
24 lib/stdlib/src/lists.erl
@@ -36,7 +36,7 @@
-export([merge/3, rmerge/3, sort/2, umerge/3, rumerge/3, usort/2]).
-export([all/2,any/2,map/2,flatmap/2,foldl/3,foldr/3,filter/2,
- partition/2,zf/2,
+ partition/2,zf/2,filtermap/2,
mapfoldl/3,mapfoldr/3,foreach/2,takewhile/2,dropwhile/2,splitwith/2,
split/2]).
@@ -1291,18 +1291,28 @@ partition(Pred, [H | T], As, Bs) ->
partition(Pred, [], As, Bs) when is_function(Pred, 1) ->
{reverse(As), reverse(Bs)}.
--spec zf(fun((T) -> boolean() | {'true', X}), [T]) -> [(T | X)].
+-spec filtermap(Fun, List1) -> List2 when
+ Fun :: fun((Elem) -> boolean() | {'true', Value}),
+ List1 :: [Elem],
+ List2 :: [Elem | Value],
+ Elem :: term(),
+ Value :: term().
-zf(F, [Hd|Tail]) ->
+filtermap(F, [Hd|Tail]) ->
case F(Hd) of
true ->
- [Hd|zf(F, Tail)];
+ [Hd|filtermap(F, Tail)];
{true,Val} ->
- [Val|zf(F, Tail)];
+ [Val|filtermap(F, Tail)];
false ->
- zf(F, Tail)
+ filtermap(F, Tail)
end;
-zf(F, []) when is_function(F, 1) -> [].
+filtermap(F, []) when is_function(F, 1) -> [].
+
+-spec zf(fun((T) -> boolean() | {'true', X}), [T]) -> [(T | X)].
+
+zf(F, L) ->
+ filtermap(F, L).
-spec foreach(Fun, List) -> ok when
Fun :: fun((Elem :: T) -> term()),
View
4 lib/stdlib/test/lists_SUITE.erl
@@ -2532,8 +2532,8 @@ otp_5939(Config) when is_list(Config) ->
?line [] = lists:filter(Pred, []),
?line {'EXIT', _} = (catch lists:partition(func, [])),
?line {[],[]} = lists:partition(Pred, []),
- ?line {'EXIT', _} = (catch lists:zf(func, [])),
- ?line [] = lists:zf(Fun1, []),
+ ?line {'EXIT', _} = (catch lists:filtermap(func, [])),
+ ?line [] = lists:filtermap(Fun1, []),
?line {'EXIT', _} = (catch lists:foreach(func, [])),
?line ok = lists:foreach(Fun1, []),
?line {'EXIT', _} = (catch lists:mapfoldl(func, [], [])),
Please sign in to comment.
Something went wrong with that request. Please try again.