Arraying your arguments – Ruby

The list of parameters passed to an object is, in fact, available as a list. To do this, we use what is called the splat operator – which is just an asterisk (*).

The splat operator is used to handle methods which have a variable parameter list. Let’s use it to create an add method that can handle any number of parameters.

We use the inject method to iterate over arguments, which is covered in the chapter on Collections. It isn’t directly relevant to this lesson, but do look it up if it piques your interest.

Example Code:

def add(*numbers)
  numbers.inject(0) { |sum, number| sum + number }
end

puts add(1)
puts add(1, 2)
puts add(1, 2, 3)
puts add(1, 2, 3, 4)

The splat operator works both ways – you can use it to convert arrays to parameter lists as easily as we just converted a parameter list to an array.

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