[erlang-questions] map over bitstring

Jesper Louis Andersen <>
Thu Oct 21 22:10:23 CEST 2010


On Thu, Oct 21, 2010 at 9:56 PM, rgowka1 <> wrote:
> Hi -
>
> How do I map a function over a bitstring without converting into string or list.
>
> For example - how can I replace << "a" >> with << "X" >> and any other
> character to << "Y" >>??
>
> InBin = << "abcaa" >>
>
> OutBin = << "XYYXX" >>

The trick is Binary Comprehensions or by using the (R14B) binary
module. Here is a solution using the Binary Comprehensions:

3> << <<case X of $a -> $X; _ -> $Y end>> || <<X>> <= <<"abcaa" >> >>.
<<"XYYXX">>

-- 
J.


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