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| author | Jesper Louis Andersen <[email protected]> | 2016-04-09 17:17:59 +0200 |
|---|---|---|
| committer | Jesper Louis Andersen <[email protected]> | 2016-04-09 17:22:37 +0200 |
| commit | c660e30a7dd781f71bed050b20c3e2d0b069e063 (patch) | |
| tree | aff243cd344c25e75787ece31d13599aef9e5195 /lib/stdlib/src/lists.erl | |
| parent | 9e3d98d67a9fbc62aa54b3035b953eb94486cdf7 (diff) | |
| download | otp-c660e30a7dd781f71bed050b20c3e2d0b069e063.tar.gz otp-c660e30a7dd781f71bed050b20c3e2d0b069e063.tar.bz2 otp-c660e30a7dd781f71bed050b20c3e2d0b069e063.zip | |
Implement lists:join/2
Add a call which works much like string:join/2 but for arbitrary lists. Provide
the function itself, lifted from Haskells Data.List standard library, provide
documentation and provide tests for the function.
Diffstat (limited to 'lib/stdlib/src/lists.erl')
| -rw-r--r-- | lib/stdlib/src/lists.erl | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/stdlib/src/lists.erl b/lib/stdlib/src/lists.erl index 2b4472cdf7..af9d63ddd6 100644 --- a/lib/stdlib/src/lists.erl +++ b/lib/stdlib/src/lists.erl @@ -39,7 +39,8 @@ -export([all/2,any/2,map/2,flatmap/2,foldl/3,foldr/3,filter/2, partition/2,zf/2,filtermap/2, mapfoldl/3,mapfoldr/3,foreach/2,takewhile/2,dropwhile/2,splitwith/2, - split/2]). + split/2, + join/2]). %%% BIFs -export([keyfind/3, keymember/3, keysearch/3, member/2, reverse/2]). @@ -1439,6 +1440,18 @@ split(N, [H|T], R) -> split(_, [], _) -> badarg. +-spec join(Sep, List1) -> List2 when + Sep :: T, + List1 :: [T], + List2 :: [T], + T :: term(). + +join(_Sep, []) -> []; +join(Sep, [H|T]) -> [H|join_prepend(Sep, T)]. + +join_prepend(_Sep, []) -> []; +join_prepend(Sep, [H|T]) -> [Sep,H|join_prepend(Sep,T)]. + %%% ================================================================= %%% Here follows the implementation of the sort functions. %%% |