Julia 1.0 Programming Complete Reference Guide

Anonymous functions

The function f(x, y) at the end of the Defining functions section can also be written with no name, as an anonymous function: (x, y) -> x^3 - y + x * y. We can, however, bind it to a name, such as f = (x, y) -> x^3 - y + x * y, and then call it, for example, as f(3, 2). Anonymous functions are also often written using the following syntax (note the space before (x)):

  function (x) 
      x + 2 
  end 
(anonymous function) 
julia> ans(3) 
5 

Often, they are also written with a lambda expression as (x) -> x + 2. Before the stab character (->) are the arguments, and after the stab character we have the return value. This can be shortened to x -> x + 2. A function without arguments would be written as () -> println("hello, Julia").