2014-03-23 19:40:19 +00:00
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---
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layout: post
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title: Joining a List of Binaries in Erlang
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description: "Description and implementation of a function that joins a list of binaries."
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2014-03-23 21:16:41 +00:00
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category: posts
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2014-03-23 19:40:19 +00:00
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tags: [erlang, programming, english]
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image:
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2014-03-24 13:42:20 +00:00
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feature: header/abstract-3.jpg
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2014-03-23 19:40:19 +00:00
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credit: dargadgetz
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creditlink: http://www.dargadgetz.com/ios-7-abstract-wallpaper-pack-for-iphone-5-and-ipod-touch-retina/
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comments: true
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share: true
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---
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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?
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There is no built-in function to do this, so I've decided to write my own.
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{% highlight erlang linenos %}
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-spec binary_join([binary()], binary()) -> binary().
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binary_join([], _Sep) ->
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<<>>;
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binary_join([Part], _Sep) ->
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Part;
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binary_join(List, Sep) ->
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InitAcc = hd(List),
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lists:foldr(fun (Value, Acc) -> <<Acc/binary, Sep/binary, Value/binary>> end, InitAcc, tl(List)).
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{% endhighlight %}
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It works just like you would expect:
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{% highlight erlang %}
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binary_join([<<"Hello">>, <<"World">>], <<", ">>) % => <<"Hello, World">>
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binary_join([<<"Hello">>], <<"...">>) % => <<"Hello">>
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{% endhighlight %}
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Hope you find this useful!
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