Comprehensions

1. Generators and filters
2. Bitstring generators
3. The :into option

In Elixir, it is common to loop over an Enumerable, often filtering out some results and mapping values into another list. Comprehensions are syntactic sugar for such constructs: they group those common tasks into the for special form.

For example, we can map a list of integers into their squared values:

iex> for n <- [1, 2, 3, 4], do: n * n
[1, 4, 9, 16]

A comprehension is made of three parts: generators, filters and collectables.