Why must I initialize variables in a class?

I am in the process of learning the new Ruby language and am a little confused as to why all variables must be initialized.

I would think that the attr_accessor method would cover this. It seems redundant to do both. Does the attr_accessor not assume that the variable is global?

Any help in explaining this would be greatly appreciated.

Solution

You don’t need to initialize anything.

If you think about the "initialize" method:

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

It's a construct you chose to do, when creating classes and organize your app. This method (initialize) will be executed when you call the new method for People: People.new.

attr_accessor gives you a setter and getter with meta-programing, meaning you don't need to type a lot of code.

Below is an example of a getter method, commonly known as a "reader", elegantly replaced with attr_reader:

def name
  @name = name
end

And the corresponding setter method, also known as a "writer" using attr_writer:

def name=(name)
  @name = name
end

Both setter and getter you can use with attr_accessor. Perhaps I digressed, but I wanted to explain the concept as I understood it since it seems you didn’t understand it well.

Short answer is, you don’t need to initialize anything if you don't want to.