Return Value in Ruby

Methods in Ruby always return exactly one object, and there is no void return even if we don’t use the return statement explicitly [1].

def hello_world
  a = "Hello World"
end

ret_val = hello_world
puts ret_val

The codes above will print:

"Hello World"

Even if we don’t call return explicitly at the end of hello_world function, Ruby will use the return value from the last evaluated statement as the return value of the function [1], which is the return value of a = "Hello World".

ret_val = puts "Hi!"
puts ret_val

The codes above will print:

Hi!
nil

In Ruby, nil is an object so the return value of puts is not void.

The multiple return values of a function will be grouped into one array since Ruby methods always return exactly one object.

def return_four_values
    return 1, 2.2, true, "Hello"
end

ret_val = return_four_values
puts ret_val.to_s, "Return class: " + ret_val.class.to_s

The codes above will print:

[1, 2.2, true, "Hello"]
Return class: Array

The multiple return values are grouped into one Array object.

The code snippets can be found here: https://github.com/yc015/Ruby-Inspect/blob/main/src/return_value.rb

References:
[1] http://ruby-for-beginners.rubymonstas.org/writing_methods/return_values.html Return values - Ruby for Beginners