blog.kempkens.io/content/posts/2014-02-16-joining-a-list-of-binaries-in-erlang.md

date	description	tags	slug	title
2014-02-16T15:30:00Z	Description and implementation of a function that joins a list of binaries.	erlang programming english	joining-a-list-of-binaries-in-erlang	Joining a List of Binaries in Erlang

The binary module in Erlang provides an easy way to split binaries using split/2,3, but what if you want to join a list of binaries back together?

There is no built-in function to do this, so I've decided to write my own.

{{< highlight erlang >}} -spec binary_join([binary()], binary()) -> binary(). binary_join([], _Sep) -> <<>>; binary_join([Part], _Sep) -> Part; binary_join([Head|Tail], Sep) -> lists:foldl(fun (Value, Acc) -> <<Acc/binary, Sep/binary, Value/binary>> end, Head, Tail). {{< / highlight >}}

It works just like you would expect:

{{< highlight erlang >}} binary_join([<<"Hello">>, <<"World">>], <<", ">>) % => <<"Hello, World">> binary_join([<<"Hello">>], <<"...">>) % => <<"Hello">> {{< / highlight >}}

Hope you find this useful!