diff options
Diffstat (limited to 'lib/stdlib/src/lists.erl')
| -rw-r--r-- | lib/stdlib/src/lists.erl | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/lib/stdlib/src/lists.erl b/lib/stdlib/src/lists.erl index d6a9f4645d..62b6ca8a21 100644 --- a/lib/stdlib/src/lists.erl +++ b/lib/stdlib/src/lists.erl @@ -3,16 +3,17 @@ %% %% Copyright Ericsson AB 1996-2013. All Rights Reserved. %% -%% The contents of this file are subject to the Erlang Public License, -%% Version 1.1, (the "License"); you may not use this file except in -%% compliance with the License. You should have received a copy of the -%% Erlang Public License along with this software. If not, it can be -%% retrieved online at http://www.erlang.org/. +%% Licensed under the Apache License, Version 2.0 (the "License"); +%% you may not use this file except in compliance with the License. +%% You may obtain a copy of the License at %% -%% Software distributed under the License is distributed on an "AS IS" -%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See -%% the License for the specific language governing rights and limitations -%% under the License. +%% http://www.apache.org/licenses/LICENSE-2.0 +%% +%% Unless required by applicable law or agreed to in writing, software +%% distributed under the License is distributed on an "AS IS" BASIS, +%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +%% See the License for the specific language governing permissions and +%% limitations under the License. %% %% %CopyrightEnd% %% @@ -22,7 +23,7 @@ -compile({no_auto_import,[min/2]}). -export([append/2, append/1, subtract/2, reverse/1, - nth/2, nthtail/2, prefix/2, suffix/2, last/1, + nth/2, nthtail/2, prefix/2, suffix/2, droplast/1, last/1, seq/2, seq/3, sum/1, duplicate/2, min/1, max/1, sublist/2, sublist/3, delete/2, unzip/1, unzip3/1, zip/2, zip3/3, zipwith/3, zipwith3/4, @@ -203,6 +204,19 @@ suffix(Suffix, List) -> Delta = length(List) - length(Suffix), Delta >= 0 andalso nthtail(Delta, List) =:= Suffix. +%% droplast(List) returns the list dropping its last element + +-spec droplast(List) -> InitList when + List :: [T, ...], + InitList :: [T], + T :: term(). + +%% This is the simple recursive implementation +%% reverse(tl(reverse(L))) is faster on average, +%% but creates more garbage. +droplast([_T]) -> []; +droplast([H|T]) -> [H|droplast(T)]. + %% last(List) returns the last element in a list. -spec last(List) -> Last when |