Rails optional argument

Question

I have a class

class Person     attr_accessor :name,:age     def initialize(name,age)         @name = name         @age = age     end end 

I'd like to make the age optional so its 0 if its not passed, or the name to be blank if not passed

Ive researched a bit on it but its a bit confusing as to what i've found (having to pass variables in another variable { }).

Answer 1

It's as simple as this:

class Person     attr_accessor :name, :age      def initialize(name = '', age = 0)         self.name = name         self.age = age     end end   Person.new('Ivan', 20) Person.new('Ivan') 

However, if you want to pass only age, the call would look pretty ugly, because you have to supply blank string for name anyway:

Person.new('', 20) 

To avoid this, there's an idiomatic way in Ruby world: options parameter.

class Person     attr_accessor :name, :age      def initialize(options = {})         self.name = options[:name] || ''         self.age = options[:age] || 0     end end  Person.new(name: 'Ivan', age: 20) Person.new(age: 20) Person.new(name: 'Ivan') 

You can put some required parameters first, and shove all the optional ones into options.

Edit

It seems that Ruby 2.0 will support real named arguments.

def example(foo: 0, bar: 1, grill: "pork chops")   puts "foo is #{foo}, bar is #{bar}, and grill is #{grill}" end  # Note that -foo is omitted and -grill precedes -bar example(grill: "lamb kebab", bar: 3.14)