Convert a binary string to Hexadecimal and vice-versa in Elixir

Question

How do you convert a binary string to a Hexadecimal String and vice-versa in Elixir?

There are a few posts on SO regarding this topic for other "main stream" languages. There's even an SO post that benchmarks various C# implementations

How do we do this in elixir?

My implementation was too ugly to share... :(

Answer 1

There is Base.encode16/2:

iex(1)> Base.encode16("foo")
"666F6F"

You can also specify the case:

iex(2)> Base.encode16("foo", case: :lower)
"666f6f"

Answer 2

I came here wanting to convert between hex strings and binary data (not strings). The accepted answer is correct, because strings in Elixir are binaries, but I found it confusing that the answer uses "foo" as an example. Base.encode16/2 / Base.decode16!/2 works for all binaries, of which strings are a subset.

Hex to binary:

Base.decode16!("0001FEFF")
=> <<0, 1, 254, 255>>

Binary to hex:

Base.encode16(<<0, 1, 255, 255>>)
=> "0001FFFF"

Base.encode16(<<0x66, 0x6F, 0x6F>>) # equivalent to "foo"
=> "666F6F"

Base.encode16("foo")
=> "666F6F"