Streams—Lazy Enumerables

In Elixir, the Enum module is greedy. This means that when you pass it a collection, it potentially consumes all the contents of that collection. It also means the result will typically be another collection. Look at the following pipeline:

[ 1, 2, 3, 4, 5 ]
|> Enum.with_index
|>​fn​ {value, index} -> value - index ​end​)
|> IO.inspect ​#=> [1,3,7,13,21]

The first map function takes the original list and creates a new list of its squares. with_index takes this list and returns a list of tuples. The next map then subtracts the index from the value, generating a list that gets passed to IO.inspect.

So, this pipeline generates four lists on its way to outputting the ...

Get Programming Elixir now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.