Is there an identity function in Elixir?

@focused is correct - 1.10-dev has added the identity function.

Documentation

Old Answer: No such function has been predefined (at least that I'm aware of). It can trivially be written as you've done in your question, or more succinctly as &(&1).

Function.identity/1 has been added to Elixir v1.10.0-dev recently:

Commit

Usage example:

Enum.map([1, 2, 3, 4], &Function.identity/1)