Pipe operator

One operator that we’ll see often is the pipe operator |>. The |> pipe operator passes the result of one function on to the next function. Conceptually, it’s like running the function:


The equivalent version using pipes is

b(:atom) |> d() |> f()

The pipe operator helps our code stay clean and readable. We’ll use it for cases where we want to transform a request type, or build up a data structure with different functions.

42 |> is_number
[1, 2, 3] |> Enum.map(fn(x) -> x * x end)
[1, 2, 3] |> Enum.map(fn(x) -> x * x end) |> Enum.reduce(&+/2)

Looking at the first line above 42 |> is_number.

What is actually happening is that 42 is being passed as the first argument to is_number so it looks like is_number(42).

What do we think is happening in the other two functions?