Programming Elixir ≥ 1.6

Binaries

The binary type represents a sequence of bits.

A binary literal looks like << term,… >>.

The simplest term is just a number from 0 to 255. The numbers are stored as successive bytes in the binary.

iex> b = << 1, 2, 3 >>
<<1, 2, 3>>
iex> byte_size b
3
iex> bit_size b
24

You can specify modifiers to set any term’s size (in bits). This is useful when working with binary formats such as media files and network packets.

iex> b = << 1::size(2), 1::size(3) >>    # 01 001
<<9::size(5)>>                           # = 9 (base 10)
iex> byte_size b
1
iex> bit_size b
5

You can store integers, floats, and other binaries in binaries.

iex> int = << 1 >>
<<1>>
iex> float = << 2.5 :: float >>
<<64, 4, 0, 0, 0, 0, 0, 0>>
iex> mix = << int ...